Add generate_subscripts, a series-generation function which generates an

array's subscripts.

Pavel Stehule, some editorialization by me.

2 files changed, 47 insertions, 0 deletions

diff --git a/src/test/regress/expected/arrays.out b/src/test/regress/expected/arrays.out
index c82cd3919b9..9ab372d15a5 100644
--- a/src/test/regress/expected/arrays.out
+++ b/src/test/regress/expected/arrays.out
@@ -903,3 +903,33 @@ select c2[2].f2 from comptable;
 drop type _comptype;
 drop table comptable;
 drop type comptype;
+create or replace function unnest1(anyarray) 
+returns setof anyelement as $$
+select $1[s] from generate_subscripts($1,1) g(s);
+$$ language sql immutable;
+create or replace function unnest2(anyarray) 
+returns setof anyelement as $$
+select $1[s1][s2] from generate_subscripts($1,1) g1(s1),
+                   generate_subscripts($1,2) g2(s2);
+$$ language sql immutable;
+select * from unnest1(array[1,2,3]);
+ unnest1 
+---------
+       1
+       2
+       3
+(3 rows)
+
+select * from unnest2(array[[1,2,3],[4,5,6]]);
+ unnest2 
+---------
+       1
+       2
+       3
+       4
+       5
+       6
+(6 rows)
+
+drop function unnest1(anyarray);
+drop function unnest2(anyarray);
diff --git a/src/test/regress/sql/arrays.sql b/src/test/regress/sql/arrays.sql
index 192648a39b6..6590cad36c4 100644
--- a/src/test/regress/sql/arrays.sql
+++ b/src/test/regress/sql/arrays.sql
@@ -340,3 +340,20 @@ select c2[2].f2 from comptable;
 drop type _comptype;
 drop table comptable;
 drop type comptype;
+
+create or replace function unnest1(anyarray) 
+returns setof anyelement as $$
+select $1[s] from generate_subscripts($1,1) g(s);
+$$ language sql immutable;
+
+create or replace function unnest2(anyarray) 
+returns setof anyelement as $$
+select $1[s1][s2] from generate_subscripts($1,1) g1(s1),
+                   generate_subscripts($1,2) g2(s2);
+$$ language sql immutable;
+
+select * from unnest1(array[1,2,3]);
+select * from unnest2(array[[1,2,3],[4,5,6]]);
+
+drop function unnest1(anyarray);
+drop function unnest2(anyarray);