Add SQL-style operators (#1322)

diff --git a/docs/content/3.manual/manual.yml b/docs/content/3.manual/manual.yml
index 94aa2476e0b80b0cd4eddd2a826f8d869bf15282..ae7a9d39e1f72ab086e0160f9241b092a2180627 100644 (file)
--- a/docs/content/3.manual/manual.yml
+++ b/docs/content/3.manual/manual.yml
@@ -1835,6 +1835,46 @@ sections:
             input: '"2015-03-05T23:51:47Z"'
             output: ['1425599507']
 
+      - title: "SQL-Style Operators"
+        body: |
+
+          jq provides a few SQL-style operators.
+
+           * INDEX(stream; index_expression):
+
+             This builtin produces an object whose keys are computed by
+             the given index expression applied to each value from the
+             given stream.
+
+           * JOIN($idx; stream; idx_expr; join_expr):
+
+             This builtin joins the values from the given stream to the
+             given index.  The index's keys are computed by applying the
+             given index expression to each value from the given stream.
+             An array of the value in the stream and the corresponding
+             value from the index is fed to the given join expression to
+             produce each result.
+
+           * JOIN($idx; stream; idx_expr):
+
+             Same as `JOIN($idx; stream; idx_expr; .)`.
+
+           * JOIN($idx; idx_expr):
+
+             This builtin joins the input `.` to the given index, applying
+             the given index expression to `.` to compute the index key.
+             The join operation is as described above.
+
+           * IN(s):
+
+             This builtin outputs `true` if `.` appears in the given
+             stream, otherwise it outputs `false`.
+
+           * IN(source; s):
+
+             This builtin outputs `true` if any value in the source stream
+             appears in the second stream, otherwise it outputs `false`.
+
   - title: Conditionals and Comparisons
     entries:
       - title: "`==`, `!=`"

diff --git a/jq.1.prebuilt b/jq.1.prebuilt
index 995b40e9abd948befd8d40cb8ce6b4c3d39c4aa9..615b033c21a28b92aa1d48758f23faa1a7b945e8 100644 (file)
--- a/jq.1.prebuilt
+++ b/jq.1.prebuilt
@@ -2005,6 +2005,45 @@ jq \'strptime("%Y\-%m\-%dT%H:%M:%SZ")|mktime\'
 .
 .IP "" 0
 .
+.SS "SQL\-Style Operators"
+jq provides a few SQL\-style operators\.
+.
+.TP
+INDEX(stream; index_expression):
+.
+.IP
+This builtin produces an object whose keys are computed by the given index expression applied to each value from the given stream\.
+.
+.TP
+JOIN($idx; stream; idx_expr; join_expr):
+.
+.IP
+This builtin joins the values from the given stream to the given index\. The index\'s keys are computed by applying the given index expression to each value from the given stream\. An array of the value in the stream and the corresponding value from the index is fed to the given join expression to produce each result\.
+.
+.TP
+JOIN($idx; stream; idx_expr):
+.
+.IP
+Same as \fBJOIN($idx; stream; idx_expr; \.)\fR\.
+.
+.TP
+JOIN($idx; idx_expr):
+.
+.IP
+This builtin joins the input \fB\.\fR to the given index, applying the given index expression to \fB\.\fR to compute the index key\. The join operation is as described above\.
+.
+.TP
+IN(s):
+.
+.IP
+This builtin outputs \fBtrue\fR if \fB\.\fR appears in the given stream, otherwise it outputs \fBfalse\fR\.
+.
+.TP
+IN(source; s):
+.
+.IP
+This builtin outputs \fBtrue\fR if any value in the source stream appears in the second stream, otherwise it outputs \fBfalse\fR\.
+.
 .SH "CONDITIONALS AND COMPARISONS"
 .
 .SS "==, !="

diff --git a/src/builtin.jq b/src/builtin.jq
index 9f6e656c215cc322111b7be68fd3b658f645d9c7..223cdcad22367f9f6fbb4127da445310c5516277 100644 (file)
--- a/src/builtin.jq
+++ b/src/builtin.jq
@@ -287,3 +287,20 @@ def walk(f):
   elif type == "array" then map( walk(f) ) | f
   else f
   end;
+
+# SQL-ish operators here:
+def INDEX(stream; idx_expr):
+  reduce stream as $row ({};
+    .[$row|idx_expr|
+      if type != "string" then tojson
+      else .
+      end] |= $row);
+def INDEX(idx_expr): INDEX(.[]; idx_expr);
+def JOIN($idx; idx_expr):
+  [.[] | [., $idx[idx_expr]]];
+def JOIN($idx; stream; idx_expr):
+  stream | [., $idx[idx_expr]];
+def JOIN($idx; stream; idx_expr; join_expr):
+  stream | [., $idx[idx_expr]] | join_expr;
+def IN(s): reduce (first(select(. == s)) | true) as $v (false; if . or $v then true else false end);
+def IN(src; s): reduce (src|IN(s)) as $v (false; if . or $v then true else false end);

diff --git a/tests/jq.test b/tests/jq.test
index 302952d566b04c74f6c8cd93f029794eb5959576..fa02b6d722ac66eb08cf202132b3134c16c9add4 100644 (file)
--- a/tests/jq.test
+++ b/tests/jq.test
@@ -1322,3 +1322,32 @@ jq: error: syntax error, unexpected INVALID_CHARACTER, expecting $end (Unix shel
 (.[{}] = 0)?
 null
 
+INDEX(range(5)|[., "foo\(.)"]; .[0])
+null
+{"0":[0,"foo0"],"1":[1,"foo1"],"2":[2,"foo2"],"3":[3,"foo3"],"4":[4,"foo4"]}
+
+JOIN({"0":[0,"abc"],"1":[1,"bcd"],"2":[2,"def"],"3":[3,"efg"],"4":[4,"fgh"]}; .[0]|tostring)
+[[5,"foo"],[3,"bar"],[1,"foobar"]]
+[[[5,"foo"],null],[[3,"bar"],[3,"efg"]],[[1,"foobar"],[1,"bcd"]]]
+
+range(5;10)|IN(range(10))
+null
+true
+true
+true
+true
+true
+
+range(10;12)|IN(range(10))
+null
+false
+false
+
+IN(range(10;20); range(10))
+null
+false
+
+IN(range(5;20); range(10))
+null
+true
+