.\" This is -*-nroff-*-
.\" XXX standard disclaimer belongs here....
-.\" $Header: /cvsroot/pgsql/src/man/Attic/built-in.3,v 1.7 1997/05/16 07:13:46 thomas Exp $
+.\" $Header: /cvsroot/pgsql/src/man/Attic/built-in.3,v 1.8 1997/07/02 14:13:14 thomas Exp $
.TH BUILT-INS INTRO 04/01/97 PostgreSQL PostgreSQL
.SH "DESCRIPTION"
This section describes the data types, functions and operators
Some date and time types share code for data input. For those types (currently
.IR datetime
and
-.IR abstime )
+.IR abstime
+, and
+.IR timespan
+and
+.IR reltime )
the input can have any of a wide variety of styles. For numeric date representations,
European and US conventions can differ, and the proper interpretation is obtained
by using the
Dates are stored internally in Greenwich Mean Time. Input and output routines
translate time to the local time zone of the server.
.PP
-All special values allowed for
-.IR "absolute time"
-are also allowed for
-.IR "datetime".
-The special values \*(lqcurrent\*(rq,
-\*(lqinfinity\*(rq and \*(lq-infinity\*(rq are provided.
-\*(lqinfinity\*(rq specifies a time later than any valid time, and
-\*(lq-infinity\*(rq specifies a time earlier than any valid time.
-\*(lqcurrent\*(rq indicates that the current time should be
+The special values `current',
+`infinity' and `-infinity' are provided.
+`infinity' specifies a time later than any valid time, and
+`-infinity' specifies a time earlier than any valid time.
+`current' indicates that the current time should be
substituted whenever this value appears in a computation.
.PP
-The strings \*(lqnow\*(rq and \*(lqepoch\*(rq can be used to specify
-time values. \*(lqnow\*(rq means the current time, and differs from
-\*(lqcurrent\*(rq in that the current time is immediately substituted
-for it. \*(lqepoch\*(rq means Jan 1 00:00:00 1970 GMT.
-
+The strings
+`now',
+`today',
+`yesterday',
+`tomorrow',
+and `epoch' can be used to specify
+time values. `now' means the current time, and differs from
+`current' in that the current time is immediately substituted
+for it. `epoch' means Jan 1 00:00:00 1970 GMT.
.SH "TIMESPAN"
General-use time span is input using a wide range of
@ Quantity Unit [Direction]
.sp
where
- Quantity is ..., '-1', '0', `1', `2', ...
+ Quantity is ..., `-1', `0', `1', `2', ...
Unit is `second', `minute', `hour', `day', `week', `month', `year',
or abbreviations or plurals of these units.
- Direction is ``ago''
+ Direction is `ago'.
.fi
.SH "ABSOLUTE TIME"
Absolute time (abstime) is a limited-range (+/- 68 years) and limited-precision (1 sec)
using Greenwich Mean Time; the input and output routines default to
the local time zone.
.PP
-The special absolute time values \*(lqcurrent\*(rq,
-\*(lqinfinity\*(rq and \*(lq-infinity\*(rq are also provided.
-\*(lqinfinity\*(rq specifies a time later than any valid time, and
-\*(lq-infinity\*(rq specifies a time earlier than any valid time.
-\*(lqcurrent\*(rq indicates that the current time should be
-substituted whenever this value appears in a computation.
-.PP
-The strings \*(lqnow\*(rq and \*(lqepoch\*(rq can be used to specify
-time values. \*(lqnow\*(rq means the current time, and differs from
-\*(lqcurrent\*(rq in that the current time is immediately substituted
-for it. \*(lqepoch\*(rq means Jan 1 00:00:00 1970 GMT.
+All special values allowed for
+.IR "datetime"
+are also allowed for
+.IR "absolute time".
.SH "RELATIVE TIME"
Relative time (reltime) is a limited-range (+/- 68 years) and limited-precision (1 sec)
.SH "FUNCTIONS"
Many data types have functions available for conversion to other related types.
In addition, there are some type-specific functions.
+.PP
+For the
+date_part() and date_trunc()
+functions, arguments can be
+`year', `month', `day', `hour', `minute', and `second',
+as well as the more specialized quantities
+`decade', `century', `millenium', `millisecond', and `microsecond'.
+date_part() also allows
+`dow'
+to return day of week and `epoch' to return seconds since 1970.
.nf
Functions:
abstime
- datetime datetime(abstime) convert to datetime
- bool isfinite(abstime) TRUE if this is a finite time
+ datetime datetime(abstime) convert to datetime
+ bool isfinite(abstime) TRUE if this is a finite time
date
- datetime datetime(date) convert to datetime
- datetime datetime(date,time) convert to datetime
+ datetime datetime(date) convert to datetime
+ datetime datetime(date,time) convert to datetime
datetime
- abstime abstime(datetime) convert to abstime
- float8 date_part(text,datetime) specified portion of date field
- bool isfinite(datetime) TRUE if this is a finite time
+ abstime abstime(datetime) convert to abstime
+ float8 date_part(text,datetime) specified portion of date field
+ datetime date_trunc(text,datetime) truncate date at specified units
+ bool isfinite(datetime) TRUE if this is a finite time
reltime
- timespan timespan(reltime) convert to timespan
+ timespan timespan(reltime) convert to timespan
time
- datetime datetime(date,time) convert to datetime
+ datetime datetime(date,time) convert to datetime
timespan
- float8 date_part(text,timespan) specified portion of time field
- bool isfinite(timespan) TRUE if this is a finite time
- reltime reltime(timespan) convert to reltime
+ float8 date_part(text,timespan) specified portion of time field
+ bool isfinite(timespan) TRUE if this is a finite time
+ reltime reltime(timespan) convert to reltime
box
- box box(point,point) convert points to box
- float8 area(box) area of box
+ box box(point,point) convert points to box
+ float8 area(box) area of box
path
- bool isopen(path) TRUE if this is an open path
- bool isclosed(path) TRUE if this is a closed path
+ bool isopen(path) TRUE if this is an open path
+ bool isclosed(path) TRUE if this is a closed path
circle
- circle circle(point,float8) convert to circle
- polygon polygon(npts,circle) convert to polygon with npts points
- float8 center(circle) radius of circle
- float8 radius(circle) radius of circle
- float8 diameter(circle) diameter of circle
- float8 area(circle) area of circle
+ circle circle(point,float8) convert to circle
+ polygon polygon(npts,circle) convert to polygon with npts points
+ float8 center(circle) radius of circle
+ float8 radius(circle) radius of circle
+ float8 diameter(circle) diameter of circle
+ float8 area(circle) area of circle
.fi
+
.SH "BINARY OPERATORS"
This list was generated from the Postgres system catalogs with the
query: