From: Peter Eisentraut Date: Sat, 6 Jan 2001 11:58:56 +0000 (+0000) Subject: Update section on SQL syntax. (Still a lot to be done though.) Add X-Git-Tag: REL7_1_BETA2~12 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3942ee389c55ecd3b9984bfc2dcf9ca30c39bf36;p=postgresql Update section on SQL syntax. (Still a lot to be done though.) Add appendix with comprehensive list of key words. --- diff --git a/doc/src/sgml/datetime.sgml b/doc/src/sgml/datetime.sgml index 5244f353b8..5a035db4b4 100644 --- a/doc/src/sgml/datetime.sgml +++ b/doc/src/sgml/datetime.sgml @@ -1,9 +1,9 @@ - + Date/Time Support diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml index 8458ae7275..799f517144 100644 --- a/doc/src/sgml/filelist.sgml +++ b/doc/src/sgml/filelist.sgml @@ -1,4 +1,4 @@ - + @@ -35,6 +35,7 @@ + diff --git a/doc/src/sgml/keywords.sgml b/doc/src/sgml/keywords.sgml new file mode 100644 index 0000000000..3ee3b93e39 --- /dev/null +++ b/doc/src/sgml/keywords.sgml @@ -0,0 +1,3163 @@ + + <acronym>SQL</acronym> Key Words + + + lists all tokens that are key words + in the SQL standard and in PostgreSQL + &version;. Background information can be found in . + + + + SQL distinguishes between reserved and + non-reserved key words. Reserved key words + are the only real key words; they are never allowed as identifiers. + Non-reserved key words only have a special meaning in particular + contexts and can be used as identifiers in other contexts. Most + non-reserved key words are actually the names of built-in tables + and functions specified by SQL and the concept of non-reserved key + words essentially only exists to declare that some predefined meaning + is attached to a word in some contexts. + + + + In the PostgreSQL parser life is a bit + more complicated. There are several different classes of tokens + ranging from those that can never be used as an identifier to those + that have absolutely no special status in the parser as compared to + an ordinary identifier. (The latter is usually the case for + functions specified by SQL.) Most SQL reserved key words are not + completely reserved in PostgreSQL, but + can be used as column label (as in SELECT 55 AS + CHECK, even though CHECK is a reserved key + word). + + + + In in the column for + PostgreSQL we classify as + non-reserved those key words that are explicitly + known to the parser but are allowed in most or all contexts where an + identifier is expected. Labeled reserved are those + tokens that are only allowed as AS column label names + (and perhaps in very few other contexts). The token + AS is the only exception: it cannot even be used as a + column label. As a general rule, if you get spurious parser errors + for commands that contain any of the listed key words as an + identifier you should try to quote the identifier to see if the + problem goes away. + + + + It is important to understand before studying that the fact that a key word is not + reserved in PostgreSQL does not mean that + the feature related to the word is not implemented. Conversely, the + presence of a key word does not indicate the existence of a feature. + + + + + + + <acronym>SQL</acronym> Key Words + + + + + Key Word + PostgreSQL + SQL 99 + SQL 92 + + + + + + ABORT + reserved + + + + + ABS + + non-reserved + + + + ABSOLUTE + non-reserved + reserved + reserved + + + ACCESS + non-reserved + + + + + ACTION + non-reserved + reserved + reserved + + + ADA + + non-reserved + non-reserved + + + ADD + non-reserved + reserved + reserved + + + ADMIN + + reserved + + + + AFTER + non-reserved + reserved + + + + AGGREGATE + non-reserved + reserved + + + + ALIAS + + reserved + + + + ALL + reserved + reserved + reserved + + + ALLOCATE + + reserved + reserved + + + ALTER + non-reserved + reserved + reserved + + + ANALYSE + reserved + + + + + ANALYZE + reserved + + + + + AND + reserved + reserved + reserved + + + ANY + reserved + reserved + reserved + + + ARE + + reserved + reserved + + + ARRAY + + reserved + + + + AS + reserved + reserved + reserved + + + ASC + reserved + reserved + reserved + + + ASENSITIVE + + non-reserved + + + + ASSERTION + + reserved + reserved + + + ASSIGNMENT + + non-reserved + + + + ASYMMETRIC + + non-reserved + + + + AT + non-reserved + reserved + reserved + + + ATOMIC + + non-reserved + + + + AUTHORIZATION + + reserved + reserved + + + AVG + + non-reserved + reserved + + + BACKWARD + non-reserved + + + + + BEFORE + non-reserved + reserved + + + + BEGIN + non-reserved + reserved + reserved + + + BETWEEN + reserved + non-reserved + reserved + + + BINARY + reserved + reserved + + + + BIT + reserved + reserved + reserved + + + BITVAR + + non-reserved + + + + BIT_LENGTH + + non-reserved + reserved + + + BLOB + + reserved + + + + BOOLEAN + + reserved + + + + BOTH + reserved + reserved + reserved + + + BREADTH + + reserved + + + + BY + non-reserved + reserved + reserved + + + C + + non-reserved + non-reserved + + + CACHE + non-reserved + + + + + CALL + + reserved + + + + CALLED + + non-reserved + + + + CARDINALITY + + non-reserved + + + + CASCADE + non-reserved + reserved + reserved + + + CASCADED + + reserved + reserved + + + CASE + reserved + reserved + reserved + + + CAST + reserved + reserved + reserved + + + CATALOG + + reserved + reserved + + + CATALOG_NAME + + non-reserved + non-reserved + + + CHAIN + non-reserved + non-reserved + + + + CHAR + reserved + reserved + reserved + + + CHARACTER + reserved + reserved + reserved + + + CHARACTERISTICS + non-reserved + + + + + CHARACTER_LENGTH + + non-reserved + reserved + + + CHARACTER_SET_CATALOG + + non-reserved + non-reserved + + + CHARACTER_SET_NAME + + non-reserved + non-reserved + + + CHARACTER_SET_SCHEMA + + non-reserved + non-reserved + + + CHAR_LENGTH + + non-reserved + reserved + + + CHECK + reserved + reserved + reserved + + + CHECKED + + non-reserved + + + + CHECKPOINT + non-reserved + + + + + CLASS + + reserved + + + + CLASS_ORIGIN + + non-reserved + non-reserved + + + CLOB + + reserved + + + + CLOSE + non-reserved + reserved + reserved + + + CLUSTER + reserved + + + + + COALESCE + reserved + non-reserved + reserved + + + COBOL + + non-reserved + non-reserved + + + COLLATE + reserved + reserved + reserved + + + COLLATION + + reserved + reserved + + + COLLATION_CATALOG + + non-reserved + non-reserved + + + COLLATION_NAME + + non-reserved + non-reserved + + + COLLATION_SCHEMA + + non-reserved + non-reserved + + + COLUMN + reserved + reserved + reserved + + + COLUMN_NAME + + non-reserved + non-reserved + + + COMMAND_FUNCTION + + non-reserved + non-reserved + + + COMMAND_FUNCTION_CODE + + non-reserved + + + + COMMENT + non-reserved + + + + + COMMIT + non-reserved + reserved + reserved + + + COMMITTED + non-reserved + non-reserved + non-reserved + + + COMPLETION + + reserved + + + + CONDITION_NUMBER + + non-reserved + non-reserved + + + CONNECT + + reserved + reserved + + + CONNECTION + + reserved + reserved + + + CONNECTION_NAME + + non-reserved + non-reserved + + + CONSTRAINT + reserved + reserved + reserved + + + CONSTRAINTS + non-reserved + reserved + reserved + + + CONSTRAINT_CATALOG + + non-reserved + non-reserved + + + CONSTRAINT_NAME + + non-reserved + non-reserved + + + CONSTRAINT_SCHEMA + + non-reserved + non-reserved + + + CONSTRUCTOR + + reserved + + + + CONTAINS + + non-reserved + + + + CONTINUE + + reserved + reserved + + + CONVERT + + non-reserved + reserved + + + COPY + reserved + + + + + CORRESPONDING + + reserved + reserved + + + COUNT + + non-reserved + reserved + + + CREATE + non-reserved + reserved + reserved + + + CREATEDB + non-reserved + + + + + CREATEUSER + non-reserved + + + + + CROSS + reserved + reserved + reserved + + + CUBE + + reserved + + + + CURRENT + + reserved + reserved + + + CURRENT_DATE + reserved + reserved + reserved + + + CURRENT_PATH + + reserved + + + + CURRENT_ROLE + + reserved + + + + CURRENT_TIME + reserved + reserved + reserved + + + CURRENT_TIMESTAMP + reserved + reserved + reserved + + + CURRENT_USER + reserved + reserved + reserved + + + CURSOR + 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+ + non-reserved + + + + LANCOMPILER + non-reserved + + + + + LANGUAGE + non-reserved + reserved + reserved + + + LARGE + + reserved + + + + LAST + + reserved + reserved + + + LATERAL + + reserved + + + + LEADING + reserved + reserved + reserved + + + LEFT + reserved + reserved + reserved + + + LENGTH + + non-reserved + non-reserved + + + LESS + + reserved + + + + LEVEL + non-reserved + reserved + reserved + + + LIKE + reserved + reserved + reserved + + + LIMIT + reserved + reserved + + + + LISTEN + reserved + + + + + LOAD + reserved + + + + + LOCAL + reserved + reserved + reserved + + + LOCALTIME + + reserved + + + + LOCALTIMESTAMP + + reserved + + + + LOCATION + non-reserved + + + + + LOCATOR + + reserved + + + + LOCK + reserved + + + + + LOWER + + non-reserved + reserved + + + M + + non-reserved + + + + MAP + + reserved + + + + MATCH + non-reserved + reserved + reserved + + + MAX + + non-reserved + reserved + + + MAXVALUE + non-reserved + + + + + MESSAGE_LENGTH + + non-reserved + non-reserved + + + MESSAGE_OCTET_LENGTH + + non-reserved + non-reserved + + + MESSAGE_TEXT + + non-reserved + non-reserved + + + METHOD + + non-reserved + + + + MIN + + non-reserved + reserved + + + MINUTE + non-reserved + reserved + reserved + + + MINVALUE + non-reserved + + + + + MOD + + non-reserved + + + + MODE + non-reserved + + + + + MODIFIES + + reserved + + + + MODIFY + + reserved + + + + MODULE + + reserved + reserved + + + MONTH + non-reserved + reserved + reserved + + + MORE + + non-reserved + non-reserved + + + MOVE + reserved + + + + + MUMPS + + non-reserved + non-reserved + + + NAME + + non-reserved + non-reserved + + + NAMES + non-reserved + reserved + reserved + + + NATIONAL + non-reserved + reserved + reserved + + + NATURAL + reserved + reserved + reserved + + + NCHAR + reserved + reserved + reserved + + + NCLOB + + reserved + + + + NEW + reserved + reserved + + + + NEXT + non-reserved + reserved + reserved + + + NO + non-reserved + reserved + reserved + + + NOCREATEDB + non-reserved + + + + + NOCREATEUSER + non-reserved + + + + + NONE + non-reserved + reserved + + + + NOT + reserved + reserved + reserved + + + NOTHING + non-reserved + + + + + NOTIFY + non-reserved + + + + + NOTNULL + reserved + + + + + NULL + reserved + reserved + reserved + + + NULLABLE + + non-reserved + non-reserved + + + NULLIF + reserved + non-reserved + reserved + + + NUMBER + + non-reserved + non-reserved + + + NUMERIC + reserved + reserved + reserved + + + OBJECT + + reserved + + + + OCTET_LENGTH + + non-reserved + reserved + + + OF + non-reserved + reserved + reserved + + + OFF + reserved + reserved + + + + OFFSET + reserved + + + + + OIDS + non-reserved + + + + + OLD + reserved + reserved + + + + ON + reserved + reserved + reserved + + + ONLY + reserved + reserved + reserved + + + OPEN + + reserved + reserved + + + OPERATION + + reserved + + + + OPERATOR + non-reserved + + + + + OPTION + non-reserved + reserved + reserved + + + OPTIONS + + non-reserved + + + + OR + reserved + reserved + reserved + + + ORDER + reserved + reserved + reserved + + + ORDINALITY + + reserved + + + + OUT + reserved + reserved + + + + OUTER + reserved + reserved + reserved + + + OUTPUT + + reserved + reserved + + + OVERLAPS + reserved + non-reserved + reserved + + + OVERLAY + + non-reserved + + + + OVERRIDING + + non-reserved + + + + OWNER + non-reserved + + + + + PAD + + reserved + reserved + + + PARAMETER + + reserved + + + + PARAMETERS + + reserved + + + + PARAMETER_MODE + + non-reserved + + + + PARAMETER_NAME + + non-reserved + + + + PARAMETER_ORDINAL_POSITION + + non-reserved + + + + PARAMETER_SPECIFIC_CATALOG + + non-reserved + + + + PARAMETER_SPECIFIC_NAME + + non-reserved + + + + PARAMETER_SPECIFIC_SCHEMA + + non-reserved + + + + PARTIAL + non-reserved + reserved + reserved + + + PASCAL + + non-reserved + non-reserved + + + PASSWORD + non-reserved + + + + + PATH + non-reserved + reserved + + + + PENDANT + non-reserved + + + + + PLI + + non-reserved + non-reserved + + + POSITION + reserved + non-reserved + reserved + + + POSTFIX + + reserved + + + + PRECISION + reserved + reserved + reserved + + + PREFIX + + reserved + + + + PREORDER + + reserved + + + + PREPARE + + reserved + reserved + + + PRESERVE + + reserved + reserved + + + PRIMARY + reserved + reserved + reserved + + + PRIOR + non-reserved + reserved + reserved + + + PRIVILEGES + non-reserved + reserved + reserved + + + PROCEDURAL + non-reserved + + + + + PROCEDURE + non-reserved + reserved + reserved + + + PUBLIC + reserved + reserved + reserved + + + READ + non-reserved + reserved + reserved + + + READS + + reserved + + + + REAL + + reserved + reserved + + + RECURSIVE + + reserved + + + + REF + + reserved + + + + REFERENCES + reserved + reserved + reserved + + + REFERENCING + + reserved + + + + REINDEX + non-reserved + + + + + RELATIVE + non-reserved + reserved + reserved + + + RENAME + non-reserved + + + + + REPEATABLE + + non-reserved + non-reserved + + + RESET + reserved + + + + + RESTRICT + non-reserved + reserved + reserved + + + RESULT + + reserved + + + + RETURN + + reserved + + + + RETURNED_LENGTH + + non-reserved + non-reserved + + + RETURNED_OCTET_LENGTH + + non-reserved + non-reserved + + + RETURNED_SQLSTATE + + non-reserved + non-reserved + + + RETURNS + non-reserved + reserved + + + + REVOKE + non-reserved + reserved + reserved + + + RIGHT + reserved + reserved + reserved + + + ROLE + + reserved + + + + ROLLBACK + non-reserved + reserved + reserved + + + ROLLUP + + reserved + + + + ROUTINE + + reserved + + + + ROUTINE_CATALOG + + non-reserved + + + + ROUTINE_NAME + + non-reserved + + + + ROUTINE_SCHEMA + + non-reserved + + + + ROW + non-reserved + reserved + + + + ROWS + + reserved + reserved + + + ROW_COUNT + + non-reserved + non-reserved + + + RULE + non-reserved + + + + + SAVEPOINT + + reserved + + + + SCALE + + non-reserved + non-reserved + + + SCHEMA + non-reserved + reserved + reserved + + + SCHEMA_NAME + + non-reserved + non-reserved + + + SCOPE + + reserved + + + + SCROLL + non-reserved + reserved + reserved + + + SEARCH + + reserved + + + + SECOND + non-reserved + reserved + reserved + + + SECTION + + reserved + reserved + + + SECURITY + + non-reserved + + + + SELECT + reserved + reserved + reserved + + + SELF + + non-reserved + + + + SENSITIVE + + non-reserved + + + + SEQUENCE + non-reserved + reserved + + + + SERIAL + non-reserved + + + + + SERIALIZABLE + non-reserved + non-reserved + non-reserved + + + SERVER_NAME + + non-reserved + non-reserved + + + SESSION + non-reserved + reserved + reserved + + + SESSION_USER + reserved + reserved + reserved + + + SET + non-reserved + reserved + reserved + + + SETOF + reserved + + + + + SETS + + reserved + + + + SHARE + non-reserved + + + + + SHOW + reserved + + + + + SIMILAR + + non-reserved + + + + SIMPLE + + non-reserved + + + + SIZE + + reserved + reserved + + + SMALLINT + + reserved + reserved + + + SOME + reserved + reserved + reserved + + + SOURCE + + non-reserved + + + + SPACE + + reserved + reserved + + + SPECIFIC + + reserved + + + + SPECIFICTYPE + + reserved + + + + SPECIFIC_NAME + + non-reserved + + + + SQL + + reserved + reserved + + + SQLCODE + + + reserved + + + SQLERROR + + + reserved + + + SQLEXCEPTION + + reserved + + + + SQLSTATE + + reserved + reserved + + + SQLWARNING + + reserved + + + + START + non-reserved + reserved + + + + STATE + + reserved + + + + STATEMENT + non-reserved + reserved + + + + STATIC + + reserved + + + + STDIN + non-reserved + + + + + STDOUT + non-reserved + + + + + STRUCTURE + + reserved + + + + STYLE + + non-reserved + + + + SUBCLASS_ORIGIN + + non-reserved + non-reserved + + + SUBLIST + + non-reserved + + + + SUBSTRING + reserved + non-reserved + reserved + + + SUM + + non-reserved + reserved + + + SYMMETRIC + + non-reserved + + + + SYSID + non-reserved + + + + + SYSTEM + + non-reserved + + + + SYSTEM_USER + + reserved + reserved + + + TABLE + reserved + reserved + reserved + + + TABLE_NAME + + non-reserved + non-reserved + + + TEMP + non-reserved + + + + + TEMPLATE + non-reserved + + + + + TEMPORARY + non-reserved + reserved + reserved + + + TERMINATE + + reserved + + + + THAN + + reserved + + + + THEN + reserved + reserved + reserved + + + TIME + non-reserved + reserved + reserved + + + TIMESTAMP + non-reserved + reserved + reserved + + + TIMEZONE_HOUR + non-reserved + reserved + reserved + + + TIMEZONE_MINUTE + non-reserved + reserved + reserved + + + TO + reserved + reserved + reserved + + + TOAST + non-reserved + + + + + TRAILING + reserved + reserved + reserved + + + TRANSACTION + reserved + reserved + reserved + + + TRANSACTIONS_COMMITTED + + non-reserved + + + + TRANSACTIONS_ROLLED_BACK + + non-reserved + + + + TRANSACTION_ACTIVE + + non-reserved + + + + TRANSFORM + + non-reserved + + + + TRANSFORMS + + non-reserved + + + + TRANSLATE + + non-reserved + reserved + + + TRANSLATION + + reserved + reserved + + + TREAT + + reserved + + + + TRIGGER + non-reserved + reserved + + + + TRIGGER_CATALOG + + non-reserved + + + + TRIGGER_NAME + + non-reserved + + + + TRIGGER_SCHEMA + + non-reserved + + + + TRIM + reserved + non-reserved + reserved + + + TRUE + reserved + reserved + reserved + + + TRUNCATE + non-reserved + + + + + TRUSTED + non-reserved + + + + + TYPE + non-reserved + non-reserved + non-reserved + + + UNCOMMITTED + + non-reserved + non-reserved + + + UNDER + + reserved + + + + UNION + reserved + reserved + reserved + + + UNIQUE + reserved + reserved + reserved + + + UNKNOWN + + reserved + reserved + + + UNLISTEN + non-reserved + + + + + UNNAMED + + non-reserved + non-reserved + + + UNNEST + + reserved + + + + UNTIL + non-reserved + + + + + UPDATE + non-reserved + reserved + reserved + + + UPPER + + non-reserved + reserved + + + USAGE + + reserved + reserved + + + USER + reserved + reserved + reserved + + + USER_DEFINED_TYPE_CATALOG + + non-reserved + + + + USER_DEFINED_TYPE_NAME + + non-reserved + + + + USER_DEFINED_TYPE_SCHEMA + + non-reserved + + + + USING + reserved + reserved + reserved + + + VACUUM + reserved + + + + + VALID + non-reserved + + + + + VALUE + + reserved + reserved + + + VALUES + non-reserved + reserved + reserved + + + VARCHAR + reserved + reserved + reserved + + + VARIABLE + + reserved + + + + VARYING + non-reserved + reserved + reserved + + + VERBOSE + reserved + + + + + VERSION + non-reserved + + + + + VIEW + non-reserved + reserved + reserved + + + WHEN + reserved + reserved + reserved + + + WHENEVER + + reserved + reserved + + + WHERE + reserved + reserved + reserved + + + WITH + non-reserved + reserved + reserved + + + WITHOUT + non-reserved + reserved + + + + WORK + non-reserved + reserved + reserved + + + WRITE + + reserved + reserved + + + YEAR + non-reserved + reserved + reserved + + + ZONE + non-reserved + reserved + reserved + + + +
+ + + diff --git a/doc/src/sgml/syntax.sgml b/doc/src/sgml/syntax.sgml index cbead926ca..4a02fab823 100644 --- a/doc/src/sgml/syntax.sgml +++ b/doc/src/sgml/syntax.sgml @@ -1,9 +1,9 @@ - - SQL Syntax + + SQL Syntax @@ -11,505 +11,325 @@ $Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.31 2000/12/22 18:57:50 pete + + Lexical Structure + + + SQL input consists of a sequence of + commands. A command is composed of a + sequence of tokens, which depend on the + syntax of the particular command, terminated by a semicolon + (;). The end of the input stream also terminates a + command. + + - SQL manipulates sets of data. The language is - composed of various key words. Arithmetic - and procedural expressions are allowed. We will cover these topics - in this chapter; subsequent chapters will include details on data - types, functions, and operators. + A token can be a key word, an + identifier, a quoted + identifier, a literal (or + constant), or a special character symbol. Tokens are normally + separated by whitespace (space, tab, newline), but need not be if + there is no ambiguity (which is generally only the case if a + special character is adjacent to some other token type). - - Key Words + + Additionally, comments can occur in SQL + input. They are not tokens, they are effectively equivalent to + whitespace. + + - SQL92 defines key words - for the language - which have specific meaning. Some key words are - reserved, which indicates that they are - restricted to appear in only certain contexts. Other key words are - not restricted, which indicates that in certain - contexts they - have a specific meaning but are not otherwise constrained. + For example, the following is (lexically) valid SQL input: + +SELECT * FROM MY_TABLE; +UPDATE MY_TABLE SET A = 5; +INSERT INTO MY_TABLE VALUES (3, 'hi there'); + + This is a sequence of three commands, one per line (although this + is not required; more than one command can be on a line, and + commands can be usefully split across lines). + + + + The SQL syntax is not very consistent regarding what tokens + identify commands and which are operands or parameters. The first + few tokens are generally the command name, so in the above example + we would usually speak of a SELECT, an + UPDATE, and an INSERT command. But + for instance the UPDATE command always requires + a SET token to appear in a certain position, and + this particular variation of INSERT also + requires a VALUES in order to be complete. The + precise syntax rules for each command are described in the + Reference Manual. + + + + Identifiers and Key Words - Postgres implements an extended subset of the - SQL92 and SQL3 languages. Some language - elements are not as restricted in this implementation as is - called for in the language standards, in part due - to the extensibility features of Postgres. + Tokens such as SELECT, UPDATE, or + VALUES in the example above are examples of + key words, that is, words that have a fixed + meaning in the SQL language. The tokens MY_TABLE + and A are examples of + identifiers. They identify names of + tables, columns, or other database objects, depending on the + command they are used in. Therefore they are sometimes simply + called names. Key words and identifiers have the + same lexical structure, meaning that one cannot know whether a + token is an identifier or a key word without knowing the language. + A complete list of key words can be found in . - Information on SQL92 and SQL3 key words - is derived from . + SQL identifiers and key words must begin with a letter + (a-z) or underscore + (_). Subsequent characters in an identifier or + key word can be letters, digits + (0-9), or underscores, + although the SQL standard will not define a key word that contains + digits or start or ends with an underscore. - - Reserved Key Words - - - SQL92 and SQL3 have - reserved key words which are not allowed - as identifiers and not allowed in any usage other than as fundamental - tokens in SQL statements. - Postgres has additional key words - which have similar restrictions. In particular, these key words - are not allowed as column or table names, though in some cases - they are allowed to be column labels (i.e. in AS clauses). - - - - - Any string can be used as an identifier if surrounded by - double quotes (like this!). Some care is required since - such an identifier will be case sensitive - and will retain embedded whitespace and most other special characters. - - - - - The following are Postgres - reserved words that are neither SQL92 - nor SQL3 reserved words. These are allowed - to be present as column labels, but not as identifiers: - - -ABORT ANALYZE -BINARY -CLUSTER CONSTRAINT COPY -DO -EXPLAIN EXTEND -LISTEN LOAD LOCK -MOVE -NEW NONE NOTIFY -OFFSET -RESET -SETOF SHOW -UNLISTEN UNTIL -VACUUM VERBOSE - - - - - The following are Postgres - reserved words that are also SQL92 - or SQL3 reserved words, and that - are allowed to be present as column labels, but not as identifiers: - - -ALL ANY ASC BETWEEN BIT BOTH -CASE CAST CHAR CHARACTER CHECK COALESCE COLLATE COLUMN - CONSTRAINT CROSS CURRENT CURRENT_DATE CURRENT_TIME - CURRENT_TIMESTAMP CURRENT_USER -DEC DECIMAL DEFAULT DESC DISTINCT -ELSE END EXCEPT EXISTS EXTRACT -FALSE FLOAT FOR FOREIGN FROM FULL -GLOBAL GROUP -HAVING -IN INNER INTERSECT INTO IS -JOIN -LEADING LEFT LIKE LOCAL -NATURAL NCHAR NOT NULL NULLIF NUMERIC -ON OR ORDER OUTER OVERLAPS -POSITION PRECISION PRIMARY PUBLIC -REFERENCES RIGHT -SELECT SESSION_USER SOME SUBSTRING -TABLE THEN TO TRANSACTION TRIM TRUE -UNION UNIQUE USER -VARCHAR -WHEN WHERE - - - The following are Postgres - reserved words that are also SQL92 - or SQL3 reserved words: - - -ADD ALTER AND AS -BEGIN BY -CASCADE CLOSE COMMIT CREATE CURSOR -DECLARE DEFAULT DELETE DESC DISTINCT DROP -EXECUTE EXISTS EXTRACT -FETCH FLOAT FOR FROM FULL -GRANT -HAVING -IN INNER INSERT INTERVAL INTO INOUT IS -JOIN -LEADING LEFT LIKE LOCAL -NAMES NATIONAL NATURAL NCHAR NO NOT NULL -ON OR OUT OUTER -PARTIAL PRIMARY PRIVILEGES PROCEDURE PUBLIC -REFERENCES REVOKE RIGHT ROLLBACK -SELECT SESSION SET SUBSTRING -TO TRAILING TRIM -UNION UNIQUE UPDATE USING -VALUES VARCHAR VARYING VIEW -WHERE WITH WITHOUT WORK - - - - - The following are SQL92 reserved key words that - are not Postgres reserved key words, but that - if used as function names are always translated into the function - CHAR_LENGTH: - - -CHARACTER_LENGTH - - - - - The following are SQL92 or SQL3 - reserved key words that - are not Postgres reserved key words, but - if used as type names are always translated into an alternate, native type: - - -BOOLEAN DOUBLE FLOAT INT INTEGER INTERVAL REAL SMALLINT - - - - - The following are not keywords of any kind, but when used in the - context of a type name are translated into a native - Postgres type, and when used in the - context of a function name are translated into a native function: - - -DATETIME TIMESPAN - - - (translated to TIMESTAMP and INTERVAL, - respectively). This feature is intended to help with - transitioning to version 7.0, and will be removed in a future release. - - - - The following are either SQL92 - or SQL3 reserved key words - that are not key words in Postgres. - These have no proscribed usage in Postgres - at the time of writing (version 7.0) but may become reserved key words in the - future: - - - - Some of these key words represent functions in SQL92. - These functions are defined in Postgres, - but the parser does not consider the names to be key words and they are allowed - in other contexts. - - - - -ALLOCATE ARE ASSERTION AT AUTHORIZATION AVG -BIT_LENGTH -CASCADED CATALOG CHAR_LENGTH CHARACTER_LENGTH COLLATION - CONNECT CONNECTION CONTINUE CONVERT CORRESPONDING COUNT - CURRENT_SESSION -DATE DEALLOCATE DEC DESCRIBE DESCRIPTOR - DIAGNOSTICS DISCONNECT DOMAIN -ESCAPE EXCEPT EXCEPTION EXEC EXTERNAL -FIRST FOUND -GET GO GOTO -IDENTITY INDICATOR INPUT INTERSECT -LAST LOWER -MAX MIN MODULE -OCTET_LENGTH OPEN OUTPUT OVERLAPS -PREPARE PRESERVE -ROWS -SCHEMA SECTION SESSION SIZE SOME - SQL SQLCODE SQLERROR SQLSTATE SUM SYSTEM_USER -TEMPORARY TRANSLATE TRANSLATION -UNKNOWN UPPER USAGE -VALUE -WHENEVER WRITE - - - - - - Non-reserved Keywords - - - SQL92 and SQL3 have - non-reserved keywords which have - a prescribed meaning in the language but which are also allowed - as identifiers. - Postgres has additional keywords - which allow similar unrestricted usage. - In particular, these keywords - are allowed as column or table names. - - - - The following are Postgres - non-reserved key words that are neither SQL92 - nor SQL3 non-reserved key words: - - -ACCESS AFTER AGGREGATE -BACKWARD BEFORE -CACHE COMMENT CREATEDB CREATEUSER CYCLE -DATABASE DELIMITERS -EACH ENCODING EXCLUSIVE -FORCE FORWARD FUNCTION -HANDLER -INCREMENT INDEX INHERITS INSENSITIVE INSTEAD ISNULL -LANCOMPILER LOCATION -MAXVALUE MINVALUE MODE -NOCREATEDB NOCREATEUSER NOTHING NOTIFY NOTNULL -OIDS OPERATOR -PASSWORD PROCEDURAL -RECIPE REINDEX RENAME RETURNS ROW RULE -SEQUENCE SERIAL SHARE START STATEMENT STDIN STDOUT -TEMP TRUSTED -UNLISTEN UNTIL -VALID VERSION - - - - - The following are Postgres - non-reserved key words that are SQL92 - or SQL3 reserved key words: - - -ABSOLUTE ACTION -CHARACTERISTICS CONSTRAINTS -DAY DEFERRABLE DEFERRED -HOUR -IMMEDIATE INITIALLY INSENSITIVE ISOLATION -KEY -LANGUAGE LEVEL -MATCH MINUTE MONTH -NEXT -OF ONLY OPTION -PATH PENDANT PRIOR PRIVILEGES -READ RELATIVE RESTRICT -SCHEMA SCROLL SECOND -TIME TIMESTAMP TIMEZONE_HOUR TIMEZONE_MINUTE TRIGGER -YEAR -ZONE - - - - - The following are Postgres - non-reserved key words that are also either SQL92 - or SQL3 non-reserved key words: - - -COMMITTED SERIALIZABLE TYPE - - - - - The following are either SQL92 - or SQL3 non-reserved key words that are not - key words of any kind in Postgres: - - -ADA -C CATALOG_NAME CHARACTER_SET_CATALOG CHARACTER_SET_NAME - CHARACTER_SET_SCHEMA CLASS_ORIGIN COBOL COLLATION_CATALOG - COLLATION_NAME COLLATION_SCHEMA COLUMN_NAME - COMMAND_FUNCTION CONDITION_NUMBER - CONNECTION_NAME CONSTRAINT_CATALOG CONSTRAINT_NAME - CONSTRAINT_SCHEMA CURSOR_NAME -DATA DATE_TIME_INTERVAL_CODE DATE_TIME_INTERVAL_PRECISION - DYNAMIC_FUNCTION -FORTRAN -LENGTH -MESSAGE_LENGTH MESSAGE_OCTET_LENGTH MORE MUMPS -NAME NULLABLE NUMBER -PAD PASCAL PLI -REPEATABLE RETURNED_LENGTH RETURNED_OCTET_LENGTH - RETURNED_SQLSTATE ROW_COUNT -SCALE SCHEMA_NAME SERVER_NAME SPACE SUBCLASS_ORIGIN -TABLE_NAME -UNCOMMITTED UNNAMED - - - - - - - Comments - - A comment - is an arbitrary sequence of characters beginning with double dashes - and extending to the end of the line, e.g.: - - --- This is a standard SQL comment - + The system uses no more than NAMEDATALEN-1 + characters of an identifier; longer names can be written in + commands, but they will be truncated. By default, + NAMEDATALEN is 32 so the maximum identifier length + is 31 (but at the time the system is built, + NAMEDATALEN can be changed in + src/include/postgres_ext.h). - We also support C-style block comments, e.g.: - - -/* multi-line comment - * with nesting: /* nested block comment */ - */ - - - where the comment begins with "/*" and extends - to the matching occurrence of "*/". These block - comments nest, as specified in SQL99, so that one can comment out - larger blocks of code that may contain existing block comments. + Identifier and key word names are case insensitive. Therefore + +UPDATE MY_TABLE SET A = 5; + + can equivalently be written as + +uPDaTE my_TabLE SeT a = 5; + + A good convention to adopt is perhaps to write key words in upper + case and names in lower case, e.g., + +UPDATE my_table SET a = 5; + - - - - Names - Names in SQL must begin with a letter - (a-z) or underscore - (_). - Subsequent characters in a name can be letters, digits - (0-9), - or underscores. The system uses no more than NAMEDATALEN-1 characters - of a name; longer names can be written in queries, but they will be - truncated. - By default, NAMEDATALEN is 32 so the maximum name length is 31 (but - at the time the system is built, NAMEDATALEN can be changed in - src/include/postgres_ext.h). + There is a second kind of identifier: the delimited + identifier or quoted + identifier. It is formed by enclosing an arbitrary + sequence of characters in double-quotes + ("). A delimited + identifier is always an identifier, never a key word. So + "select" could be used to refer to a column or + table named select, whereas an unquoted + select would be taken as part of a command and + would therefore provoke a parse error when used where a table or + column name is expected. The example can be written with quoted + identifiers like so: + +UPDATE "my_table" SET "a" = 5; + - Names containing other characters may be formed by surrounding them - with double quotes ("). For example, table or column - names may contain - otherwise disallowed characters such as spaces, ampersands, etc. if - quoted. Quoting a name also makes it case-sensitive, - whereas unquoted names are always folded to lower case. For example, - the names FOO, foo - and "foo" are - considered the same by Postgres, but - "Foo" is a different name. + Quoted identifiers can contain any character other than a double + quote itself. This allows constructing table or column names that + would otherwise not be possible, such as ones containing spaces or + ampersands. The length limitation still applies. - Double quotes can also be used to protect a name that would otherwise - be taken to be an SQL keyword. For example, IN - is a keyword but "IN" is a name. + Quoting an identifier also makes it case-sensitive, whereas + unquoted names are always folded to lower case. For example, the + identifiers FOO, foo and + "foo" are considered the same by + Postgres, but "Foo" + and "FOO" are different from these three and + each other. + + + This is incompatible with SQL, where unquoted names are folded to + upper case. Thus, foo is equivalent to + "FOO". If you want to write portable + applications you are advised to always quote a particular name or + never quote it. + + - + + - + Constants - There are three kinds of implicitly typed constants - in Postgres: strings, integers, - and floating point numbers. Constants can - also be specified with explicit types, which can enable more - accurate representation and more efficient handling by the - backend. The implicit constants are described below; explicit + There are four kinds of implicitly typed + constants in Postgres: + strings, bit strings, integers, and floating point numbers. + Constants can also be specified with explicit types, which can + enable more accurate representation and more efficient handling by + the system. The implicit constants are described below; explicit constants are discussed afterwards. - + String Constants - Strings - in SQL are arbitrary sequences of ASCII characters bounded by single - quotes ("'", e.g. 'This is a string'). - SQL92 allows single quotes to be embedded in strings by typing two - adjacent single quotes (e.g. 'Dianne''s horse'). - In Postgres single quotes may alternatively - be escaped with a backslash ("\", e.g. - 'Dianne\'s horse'). To include a + A string constant in SQL is an arbitrary sequence of characters + bounded by single quotes ('), e.g., 'This + is a string'. SQL allows single quotes to be embedded + in strings by typing two adjacent single quotes (e.g., + 'Dianne''s horse'). In + Postgres single quotes may + alternatively be escaped with a backslash (\, + e.g., 'Dianne\'s horse'). + + + + C-style backslash escapes are also available: + \b is a backspace, \f is a + form feed, \n is a newline, + \r is a carriage return, \t + is a tab, and \xxx, + where xxx is an octal number, is the + character with the corresponding ASCII code. Any other character + following a backslash is taken literally. Thus, to include a backslash in a string constant, type two backslashes. - Non-printing characters may also be embedded within strings by - prepending them with a backslash - (e.g. '\tab'). - + + The character with the code zero cannot be in a string constant. + - - Integer Constants + + Two string constants that are only separated by whitespace + with at least one newline are concatenated + and effectively treated as if the string had been written in one + constant. For example: + +SELECT 'foo' +'bar'; + + is equivalent to + +SELECT 'foobar'; + + but + +SELECT 'foo' 'bar'; + + is not valid syntax. + + + + + Bit String Constants - Integer constants - in SQL are sequences of ASCII digits with no decimal point. - The range of legal values depends on which integer datatype is - used, but the plain integer type accepts values - ranging from -2147483648 to +2147483647. + Bit string constants look like string constants with a + B (upper or lower case) immediately before the + opening quote (no intervening whitespace), e.g., + B'1001'. The only characters allowed within + bit string constants are 0 and + 1. Bit strings constants can be continued + across lines in the same way as regular string constants. - + - - Floating Point Constants + + Integer Constants - Floating point constants - consist of an integer part, a decimal point, and a fraction part or - scientific notation of the following format: + Integer constants in SQL are sequences of decimal digits (0 + though 9) with no decimal point. The range of legal values + depends on which integer data type is used, but the plain + integer type accepts values ranging from -2147483648 + to +2147483647. (The optional plus or minus sign is actually a + separate unary operator and not part of the integer constant.) + + - -{dig}.{dig} [e [+-] {dig}] - + + Floating Point Constants - where dig is one or more digits. - You must include at least one dig after the - period and after the [+-] if you use those options. An exponent with - a missing mantissa has a mantissa of 1 inserted. There may be no - extra characters embedded in the string. + + Floating point constants are accepted in these general forms: + +digits.digitse+-digits +digits.digitse+-digits +digitse+-digits + + where digits is one or more decimal + digits. At least one digit must be before or after the decimal + point and after the e if you use that option. + Thus, a floating point constant is distinguished from an integer + constant by the presence of either the decimal point or the + exponent clause (or both). There must not be a space or other + characters embedded in the constant. + + + These are some examples of valid floating point constants: + +3.5 +4. +.001 +5e2 +1.925e-3 + + + + - Floating point constaints are of type - float8. float4 can be specified - explicitly by using SQL92 string notation or + Floating point constants are of type DOUBLE + PRECISION. REAL can be specified explicitly + by using SQL string notation or Postgres type notation: - -float4 '1.23' -- string style -'1.23'::float4 -- Postgres (historical) style + +REAL '1.23' -- string style +'1.23'::REAL -- Postgres (historical) style - + - - Constants of Postgres User-Defined Types + + Constants of Other Types - A constant of an - arbitrary - type can be entered using any one of the following notations: - - + A constant of an arbitrary type can be + entered using any one of the following notations: + type 'string' 'string'::type CAST ( 'string' AS type ) - - - The value inside the string is passed to the input - conversion routine for the type called - type. The result is a - constant of the indicated type. The explicit typecast may be omitted - if there is no ambiguity as to the type the constant must be, in which - case it is automatically coerced. + + The value inside the string is passed to the input conversion + routine for the type called type. The + result is a constant of the indicated type. The explicit type + cast may be omitted if there is no ambiguity as to the type the + constant must be (for example, when it is passed as an argument + to a non-overloaded function), in which case it is automatically + coerced. It is also possible to specify a type coercion using a function-like syntax: - - + typename ( value ) - - + although this only works for types whose names are also valid as function names. (For example, double precision can't be used this way --- but the equivalent float8 @@ -517,52 +337,222 @@ CAST ( 'string' AS type ) - The ::, CAST(), and function-call - syntaxes can also be used to specify run-time type conversions. But - the form type - 'string' can only be used to specify the - type of a literal constant. + The ::, CAST(), and + function-call syntaxes can also be used to specify the type of + arbitrary expressions, but the form + type + 'string' can only be used to specify + the type of a literal constant. - + - + Array constants - Array constants - are n-dimensional arrays of any Postgres datatype. The general format of an array constant is the following: - - -{ val1 delim val2 delim ... } - - - where delim - is the delimiter character for the type, as recorded in its - pg_type class entry. - (For all built-in types, this is the comma character ",".) - Each val is either a constant - of the array element type, or a sub-array. - An example of an array constant is - - -{{1,2,3},{4,5,6},{7,8,9}} - - + +'{ val1 delim val2 delim ... }' + + where delim is the delimiter character + for the type, as recorded in its pg_type + entry. (For all built-in types, this is the comma character + ",".) Each val is either a constant + of the array element type, or a sub-array. An example of an + array constant is + +'{{1,2,3},{4,5,6},{7,8,9}}' + This constant is a two-dimensional, 3 by 3 array consisting of three sub-arrays of integers. Individual array elements can be placed between double-quote - marks (") to avoid ambiguity problems with respect to - white space. - Without quote marks, the array-value parser will skip leading white space. + marks (") to avoid ambiguity + problems with respect to white space. Without quote marks, the + array-value parser will skip leading white space. - - - + + (Array constants are actually only a special case of the generic + type constants discussed in the previous section. The constant + is initially treated as a string and passed to the array input + conversion routine. An explicit type specification might be + necessary.) + + + + + + + Operators + + + An operator is a sequence of up to NAMEDATALEN-1 + (31 by default) characters from the following list: + ++ - * / < > = ~ ! @ # % ^ & | ` ? $ + + + There are a few restrictions on operator names, however: + + + + "$" (dollar) cannot be a single-character operator, although it + can be part of a multi-character operator name. + + + + + + -- and /* cannot appear + anywhere in an operator name, since they will be taken as the + start of a comment. + + + + + + A multi-character operator name cannot end in "+" or "-", + unless the name also contains at least one of these characters: + +~ ! @ # % ^ & | ` ? $ + + For example, @- is an allowed operator name, + but *- is not. This restriction allows + Postgres to parse SQL-compliant + queries without requiring spaces between tokens. + + + + + + + When working with non-SQL-standard operator names, you will usually + need to separate adjacent operators with spaces to avoid ambiguity. + For example, if you have defined a left-unary operator named "@", + you cannot write X*@Y; you must write + X* @Y to ensure that + Postgres reads it as two operator names + not one. + + + + + Special Characters + + + Some characters that are not alphanumeric have a special meaning + that is different from being an operator. Details on the usage can + be found at the location where the respective syntax element is + described. This section only exists to advise the existence and + summarize the purposes of these characters. + + + + + A dollar sign ($) followed by digits is used + to represent the positional parameters in the body of a function + definition. In other contexts the dollar sign may be part of an + operator name. + + + + + + Parentheses (()) have their usual meaning to + group expressions and enforce precedence. In some cases + parentheses are required as part of the fixed syntax of a + particular SQL command. + + + + + + Brackets ([]) are used to select the elements + of an array. See for more information + on arrays. + + + + + + Commas (,) are used in some syntactical + constructs to separate the elements of a list. + + + + + + The semicolon (;) terminates an SQL command. + It cannot appear anywhere within a command, except when quoted + as a string constant or identifier. + + + + + + The colon (:) is used to select + slices from arrays. (See .) In certain SQL dialects (such as Embedded + SQL), the colon is used to prefix variable names. + + + + + + The asterisk (*) has a special meaning when + used in the SELECT command or with the + COUNT aggregate function. + + + + + + The period (.) is used in floating point + constants, and to separate table and column names. + + + + + + + + + Comments + + + A comment is an arbitrary sequence of characters beginning with + double dashes and extending to the end of the line, e.g.: + +-- This is a standard SQL92 comment + + + + + Alternatively, C-style block comments can be used: + +/* multi-line comment + * with nesting: /* nested block comment */ + */ + + where the comment begins with /* and extends to + the matching occurrence of */. These block + comments nest, as specified in SQL99 but unlike C, so that one can + comment out larger blocks of code that may contain existing block + comments. + + + + A comment is removed from the input stream before further syntax + analysis and is effectively replaced by whitespace. + + + + + + Fields and Columns @@ -664,18 +654,6 @@ CAST ( 'string' AS type ) - - Operators - - - Any built-in or user-defined operator may be used in SQL. - For the list of built-in operators consult . - For a list of user-defined operators consult your system administrator - or run a query on the pg_operator class. - Parentheses may be used for arbitrary grouping of operators in expressions. - - - Expressions diff --git a/doc/src/sgml/user.sgml b/doc/src/sgml/user.sgml index e2f7874483..d1275e0173 100644 --- a/doc/src/sgml/user.sgml +++ b/doc/src/sgml/user.sgml @@ -1,5 +1,5 @@ @@ -62,6 +62,7 @@ $Header: /cvsroot/pgsql/doc/src/sgml/Attic/user.sgml,v 1.22 2000/12/16 02:29:36 &datetime; + &keywords; &biblio;