diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index ac6347a971..4c1a2d794c 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -19181,6 +19181,29 @@ SELECT NULLIF(value, '(none)') ...
{[1,2)}
+
+
+
+
+ unnest
+ for multirange
+
+ unnest ( anymultirange )
+ setof anyrange
+
+
+ Expands a multirange into a set of ranges.
+ The ranges are read out in storage order (ascending).
+
+
+ unnest('{[1,2), [3,4)}'::int4multirange)
+
+
+ [1,2)
+ [3,4)
+
+
+
diff --git a/src/backend/utils/adt/multirangetypes.c b/src/backend/utils/adt/multirangetypes.c
index 7aeec7617f..7076a60c32 100644
--- a/src/backend/utils/adt/multirangetypes.c
+++ b/src/backend/utils/adt/multirangetypes.c
@@ -34,6 +34,7 @@
#include "access/tupmacs.h"
#include "common/hashfn.h"
+#include "funcapi.h"
#include "lib/stringinfo.h"
#include "libpq/pqformat.h"
#include "miscadmin.h"
@@ -2645,6 +2646,78 @@ range_merge_from_multirange(PG_FUNCTION_ARGS)
PG_RETURN_RANGE_P(result);
}
+/* Turn multirange into a set of ranges */
+Datum
+multirange_unnest(PG_FUNCTION_ARGS)
+{
+ typedef struct
+ {
+ MultirangeType *mr;
+ TypeCacheEntry *typcache;
+ int index;
+ } multirange_unnest_fctx;
+
+ FuncCallContext *funcctx;
+ multirange_unnest_fctx *fctx;
+ MemoryContext oldcontext;
+
+ /* stuff done only on the first call of the function */
+ if (SRF_IS_FIRSTCALL())
+ {
+ MultirangeType *mr;
+
+ /* create a function context for cross-call persistence */
+ funcctx = SRF_FIRSTCALL_INIT();
+
+ /*
+ * switch to memory context appropriate for multiple function calls
+ */
+ oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+
+ /*
+ * Get the multirange value and detoast if needed. We can't do this
+ * earlier because if we have to detoast, we want the detoasted copy
+ * to be in multi_call_memory_ctx, so it will go away when we're done
+ * and not before. (If no detoast happens, we assume the originally
+ * passed multirange will stick around till then.)
+ */
+ mr = PG_GETARG_MULTIRANGE_P(0);
+
+ /* allocate memory for user context */
+ fctx = (multirange_unnest_fctx *) palloc(sizeof(multirange_unnest_fctx));
+
+ /* initialize state */
+ fctx->mr = mr;
+ fctx->index = 0;
+ fctx->typcache = lookup_type_cache(MultirangeTypeGetOid(mr),
+ TYPECACHE_MULTIRANGE_INFO);
+
+ funcctx->user_fctx = fctx;
+ MemoryContextSwitchTo(oldcontext);
+ }
+
+ /* stuff done on every call of the function */
+ funcctx = SRF_PERCALL_SETUP();
+ fctx = funcctx->user_fctx;
+
+ if (fctx->index < fctx->mr->rangeCount)
+ {
+ RangeType *range;
+
+ range = multirange_get_range(fctx->typcache->rngtype,
+ fctx->mr,
+ fctx->index);
+ fctx->index++;
+
+ SRF_RETURN_NEXT(funcctx, RangeTypePGetDatum(range));
+ }
+ else
+ {
+ /* do when there is no more left */
+ SRF_RETURN_DONE(funcctx);
+ }
+}
+
/* Hash support */
/* hash a multirange value */
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 8bf9d704b7..8cd0252082 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -10541,6 +10541,10 @@
proname => 'range_intersect_agg', prokind => 'a', proisstrict => 'f',
prorettype => 'anymultirange', proargtypes => 'anymultirange',
prosrc => 'aggregate_dummy' },
+{ oid => '1293', descr => 'expand multirange to set of ranges',
+ proname => 'unnest', prorows => '100',
+ proretset => 't', prorettype => 'anyrange', proargtypes => 'anymultirange',
+ prosrc => 'multirange_unnest' },
# date, time, timestamp constructors
{ oid => '3846', descr => 'construct date',
diff --git a/src/test/regress/expected/multirangetypes.out b/src/test/regress/expected/multirangetypes.out
index af3ef4a258..7f689ad41b 100644
--- a/src/test/regress/expected/multirangetypes.out
+++ b/src/test/regress/expected/multirangetypes.out
@@ -346,6 +346,23 @@ select textrange(null, null)::textmultirange;
{(,)}
(1 row)
+--
+-- test unnest(multirange) function
+--
+select unnest(int4multirange(int4range('5', '6'), int4range('1', '2')));
+ unnest
+--------
+ [1,2)
+ [5,6)
+(2 rows)
+
+select unnest(textmultirange(textrange('a', 'b'), textrange('d', 'e')));
+ unnest
+--------
+ [a,b)
+ [d,e)
+(2 rows)
+
--
-- create some test data and test the operators
--
@@ -2938,6 +2955,13 @@ LINE 1: select multirange_of_text(textrange2('a','Z'));
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
select multirange_of_text(textrange1('a','Z')) @> 'b'::text;
ERROR: range lower bound must be less than or equal to range upper bound
+select unnest(multirange_of_text(textrange1('a','b'), textrange1('d','e')));
+ unnest
+--------
+ [a,b)
+ [d,e)
+(2 rows)
+
select _textrange1(textrange2('a','z')) @> 'b'::text;
?column?
----------
diff --git a/src/test/regress/sql/multirangetypes.sql b/src/test/regress/sql/multirangetypes.sql
index b91a23e0d5..ad50afc0f5 100644
--- a/src/test/regress/sql/multirangetypes.sql
+++ b/src/test/regress/sql/multirangetypes.sql
@@ -77,6 +77,12 @@ select textrange('a', 'c')::textmultirange;
select textrange('a', null)::textmultirange;
select textrange(null, null)::textmultirange;
+--
+-- test unnest(multirange) function
+--
+select unnest(int4multirange(int4range('5', '6'), int4range('1', '2')));
+select unnest(textmultirange(textrange('a', 'b'), textrange('d', 'e')));
+
--
-- create some test data and test the operators
--
@@ -658,6 +664,7 @@ create type textrange2 as range(subtype=text, multirange_type_name=_textrange1,
select multirange_of_text(textrange2('a','Z')); -- should fail
select multirange_of_text(textrange1('a','Z')) @> 'b'::text;
+select unnest(multirange_of_text(textrange1('a','b'), textrange1('d','e')));
select _textrange1(textrange2('a','z')) @> 'b'::text;
drop type textrange1;