+-- check some cases that were handled incorrectly in 8.3.0
+explain (costs off)
+ select distinct max(unique2) from tenk1;
+ QUERY PLAN
+---------------------------------------------------------------------
+ HashAggregate
+ Group Key: $0
+ InitPlan 1 (returns $0)
+ -> Limit
+ -> Index Only Scan Backward using tenk1_unique2 on tenk1
+ Index Cond: (unique2 IS NOT NULL)
+ -> Result
+(7 rows)
+
+select distinct max(unique2) from tenk1;
+ max
+------
+ 9999
+(1 row)
+
+explain (costs off)
+ select max(unique2) from tenk1 order by 1;
+ QUERY PLAN
+---------------------------------------------------------------------
+ Sort
+ Sort Key: ($0)
+ InitPlan 1 (returns $0)
+ -> Limit
+ -> Index Only Scan Backward using tenk1_unique2 on tenk1
+ Index Cond: (unique2 IS NOT NULL)
+ -> Result
+(7 rows)
+
+select max(unique2) from tenk1 order by 1;
+ max
+------
+ 9999
+(1 row)
+
+explain (costs off)
+ select max(unique2) from tenk1 order by max(unique2);
+ QUERY PLAN
+---------------------------------------------------------------------
+ Sort
+ Sort Key: ($0)
+ InitPlan 1 (returns $0)
+ -> Limit
+ -> Index Only Scan Backward using tenk1_unique2 on tenk1
+ Index Cond: (unique2 IS NOT NULL)
+ -> Result
+(7 rows)
+
+select max(unique2) from tenk1 order by max(unique2);
+ max
+------
+ 9999
+(1 row)
+
+explain (costs off)
+ select max(unique2) from tenk1 order by max(unique2)+1;
+ QUERY PLAN
+---------------------------------------------------------------------
+ Sort
+ Sort Key: (($0 + 1))
+ InitPlan 1 (returns $0)
+ -> Limit
+ -> Index Only Scan Backward using tenk1_unique2 on tenk1
+ Index Cond: (unique2 IS NOT NULL)
+ -> Result
+(7 rows)
+
+select max(unique2) from tenk1 order by max(unique2)+1;
+ max
+------
+ 9999
+(1 row)
+
+explain (costs off)
+ select max(unique2), generate_series(1,3) as g from tenk1 order by g desc;
+ QUERY PLAN
+---------------------------------------------------------------------
+ Sort
+ Sort Key: (generate_series(1, 3))
+ InitPlan 1 (returns $0)
+ -> Limit
+ -> Index Only Scan Backward using tenk1_unique2 on tenk1
+ Index Cond: (unique2 IS NOT NULL)
+ -> Result
+(7 rows)
+
+select max(unique2), generate_series(1,3) as g from tenk1 order by g desc;
+ max | g
+------+---
+ 9999 | 3
+ 9999 | 2
+ 9999 | 1
+(3 rows)
+
+-- try it on an inheritance tree
+create table minmaxtest(f1 int);
+create table minmaxtest1() inherits (minmaxtest);
+create table minmaxtest2() inherits (minmaxtest);
+create table minmaxtest3() inherits (minmaxtest);
+create index minmaxtesti on minmaxtest(f1);
+create index minmaxtest1i on minmaxtest1(f1);
+create index minmaxtest2i on minmaxtest2(f1 desc);
+create index minmaxtest3i on minmaxtest3(f1) where f1 is not null;
+insert into minmaxtest values(11), (12);
+insert into minmaxtest1 values(13), (14);
+insert into minmaxtest2 values(15), (16);
+insert into minmaxtest3 values(17), (18);
+explain (costs off)
+ select min(f1), max(f1) from minmaxtest;
+ QUERY PLAN
+----------------------------------------------------------------------------------------------
+ Result
+ InitPlan 1 (returns $0)
+ -> Limit
+ -> Merge Append
+ Sort Key: minmaxtest.f1
+ -> Index Only Scan using minmaxtesti on minmaxtest
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan using minmaxtest1i on minmaxtest1
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan Backward using minmaxtest2i on minmaxtest2
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan using minmaxtest3i on minmaxtest3
+ Index Cond: (f1 IS NOT NULL)
+ InitPlan 2 (returns $1)
+ -> Limit
+ -> Merge Append
+ Sort Key: minmaxtest_1.f1
+ -> Index Only Scan Backward using minmaxtesti on minmaxtest minmaxtest_1
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan Backward using minmaxtest1i on minmaxtest1 minmaxtest1_1
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan using minmaxtest2i on minmaxtest2 minmaxtest2_1
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan Backward using minmaxtest3i on minmaxtest3 minmaxtest3_1
+ Index Cond: (f1 IS NOT NULL)
+(25 rows)
+
+select min(f1), max(f1) from minmaxtest;
+ min | max
+-----+-----
+ 11 | 18
+(1 row)
+
+-- DISTINCT doesn't do anything useful here, but it shouldn't fail
+explain (costs off)
+ select distinct min(f1), max(f1) from minmaxtest;
+ QUERY PLAN
+----------------------------------------------------------------------------------------------
+ HashAggregate
+ Group Key: $0, $1
+ InitPlan 1 (returns $0)
+ -> Limit
+ -> Merge Append
+ Sort Key: minmaxtest.f1
+ -> Index Only Scan using minmaxtesti on minmaxtest
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan using minmaxtest1i on minmaxtest1
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan Backward using minmaxtest2i on minmaxtest2
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan using minmaxtest3i on minmaxtest3
+ Index Cond: (f1 IS NOT NULL)
+ InitPlan 2 (returns $1)
+ -> Limit
+ -> Merge Append
+ Sort Key: minmaxtest_1.f1
+ -> Index Only Scan Backward using minmaxtesti on minmaxtest minmaxtest_1
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan Backward using minmaxtest1i on minmaxtest1 minmaxtest1_1
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan using minmaxtest2i on minmaxtest2 minmaxtest2_1
+ Index Cond: (f1 IS NOT NULL)
+ -> Index Only Scan Backward using minmaxtest3i on minmaxtest3 minmaxtest3_1
+ Index Cond: (f1 IS NOT NULL)
+ -> Result
+(27 rows)
+
+select distinct min(f1), max(f1) from minmaxtest;
+ min | max
+-----+-----
+ 11 | 18
+(1 row)
+
+drop table minmaxtest cascade;
+NOTICE: drop cascades to 3 other objects
+DETAIL: drop cascades to table minmaxtest1
+drop cascades to table minmaxtest2
+drop cascades to table minmaxtest3
+-- check for correct detection of nested-aggregate errors
+select max(min(unique1)) from tenk1;
+ERROR: aggregate function calls cannot be nested
+LINE 1: select max(min(unique1)) from tenk1;
+ ^
+select (select max(min(unique1)) from int8_tbl) from tenk1;
+ERROR: aggregate function calls cannot be nested
+LINE 1: select (select max(min(unique1)) from int8_tbl) from tenk1;
+ ^
+--
+-- Test combinations of DISTINCT and/or ORDER BY
+--
+select array_agg(a order by b)
+ from (values (1,4),(2,3),(3,1),(4,2)) v(a,b);
+ array_agg
+-----------
+ {3,4,2,1}
+(1 row)
+
+select array_agg(a order by a)
+ from (values (1,4),(2,3),(3,1),(4,2)) v(a,b);
+ array_agg
+-----------
+ {1,2,3,4}
+(1 row)
+
+select array_agg(a order by a desc)
+ from (values (1,4),(2,3),(3,1),(4,2)) v(a,b);
+ array_agg
+-----------
+ {4,3,2,1}
+(1 row)
+
+select array_agg(b order by a desc)
+ from (values (1,4),(2,3),(3,1),(4,2)) v(a,b);
+ array_agg
+-----------
+ {2,1,3,4}
+(1 row)
+
+select array_agg(distinct a)
+ from (values (1),(2),(1),(3),(null),(2)) v(a);
+ array_agg
+--------------
+ {1,2,3,NULL}
+(1 row)
+
+select array_agg(distinct a order by a)
+ from (values (1),(2),(1),(3),(null),(2)) v(a);
+ array_agg
+--------------
+ {1,2,3,NULL}
+(1 row)
+
+select array_agg(distinct a order by a desc)
+ from (values (1),(2),(1),(3),(null),(2)) v(a);
+ array_agg
+--------------
+ {NULL,3,2,1}
+(1 row)
+
+select array_agg(distinct a order by a desc nulls last)
+ from (values (1),(2),(1),(3),(null),(2)) v(a);
+ array_agg
+--------------
+ {3,2,1,NULL}
+(1 row)
+
+-- multi-arg aggs, strict/nonstrict, distinct/order by
+select aggfstr(a,b,c)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c);
+ aggfstr
+---------------------------------------
+ {"(1,3,foo)","(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+select aggfns(a,b,c)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c);
+ aggfns
+-----------------------------------------------
+ {"(1,3,foo)","(0,,)","(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+select aggfstr(distinct a,b,c)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,3) i;
+ aggfstr
+---------------------------------------
+ {"(1,3,foo)","(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+select aggfns(distinct a,b,c)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,3) i;
+ aggfns
+-----------------------------------------------
+ {"(0,,)","(1,3,foo)","(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+select aggfstr(distinct a,b,c order by b)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,3) i;
+ aggfstr
+---------------------------------------
+ {"(3,1,baz)","(2,2,bar)","(1,3,foo)"}
+(1 row)
+
+select aggfns(distinct a,b,c order by b)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,3) i;
+ aggfns
+-----------------------------------------------
+ {"(3,1,baz)","(2,2,bar)","(1,3,foo)","(0,,)"}
+(1 row)
+
+-- test specific code paths
+select aggfns(distinct a,a,c order by c using ~<~,a)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,2) i;
+ aggfns
+------------------------------------------------
+ {"(2,2,bar)","(3,3,baz)","(1,1,foo)","(0,0,)"}
+(1 row)
+
+select aggfns(distinct a,a,c order by c using ~<~)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,2) i;
+ aggfns
+------------------------------------------------
+ {"(2,2,bar)","(3,3,baz)","(1,1,foo)","(0,0,)"}
+(1 row)
+
+select aggfns(distinct a,a,c order by a)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,2) i;
+ aggfns
+------------------------------------------------
+ {"(0,0,)","(1,1,foo)","(2,2,bar)","(3,3,baz)"}
+(1 row)
+
+select aggfns(distinct a,b,c order by a,c using ~<~,b)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,2) i;
+ aggfns
+-----------------------------------------------
+ {"(0,,)","(1,3,foo)","(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+-- check node I/O via view creation and usage, also deparsing logic
+create view agg_view1 as
+ select aggfns(a,b,c)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c);
+select * from agg_view1;
+ aggfns
+-----------------------------------------------
+ {"(1,3,foo)","(0,,)","(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+select pg_get_viewdef('agg_view1'::regclass);
+ pg_get_viewdef
+---------------------------------------------------------------------------------------------------------------------
+ SELECT aggfns(v.a, v.b, v.c) AS aggfns +
+ FROM ( VALUES (1,3,'foo'::text), (0,NULL::integer,NULL::text), (2,2,'bar'::text), (3,1,'baz'::text)) v(a, b, c);
+(1 row)
+
+create or replace view agg_view1 as
+ select aggfns(distinct a,b,c)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,3) i;
+select * from agg_view1;
+ aggfns
+-----------------------------------------------
+ {"(0,,)","(1,3,foo)","(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+select pg_get_viewdef('agg_view1'::regclass);
+ pg_get_viewdef
+---------------------------------------------------------------------------------------------------------------------
+ SELECT aggfns(DISTINCT v.a, v.b, v.c) AS aggfns +
+ FROM ( VALUES (1,3,'foo'::text), (0,NULL::integer,NULL::text), (2,2,'bar'::text), (3,1,'baz'::text)) v(a, b, c),+
+ generate_series(1, 3) i(i);
+(1 row)
+
+create or replace view agg_view1 as
+ select aggfns(distinct a,b,c order by b)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,3) i;
+select * from agg_view1;
+ aggfns
+-----------------------------------------------
+ {"(3,1,baz)","(2,2,bar)","(1,3,foo)","(0,,)"}
+(1 row)
+
+select pg_get_viewdef('agg_view1'::regclass);
+ pg_get_viewdef
+---------------------------------------------------------------------------------------------------------------------
+ SELECT aggfns(DISTINCT v.a, v.b, v.c ORDER BY v.b) AS aggfns +
+ FROM ( VALUES (1,3,'foo'::text), (0,NULL::integer,NULL::text), (2,2,'bar'::text), (3,1,'baz'::text)) v(a, b, c),+
+ generate_series(1, 3) i(i);
+(1 row)
+
+create or replace view agg_view1 as
+ select aggfns(a,b,c order by b+1)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c);
+select * from agg_view1;
+ aggfns
+-----------------------------------------------
+ {"(3,1,baz)","(2,2,bar)","(1,3,foo)","(0,,)"}
+(1 row)
+
+select pg_get_viewdef('agg_view1'::regclass);
+ pg_get_viewdef
+---------------------------------------------------------------------------------------------------------------------
+ SELECT aggfns(v.a, v.b, v.c ORDER BY (v.b + 1)) AS aggfns +
+ FROM ( VALUES (1,3,'foo'::text), (0,NULL::integer,NULL::text), (2,2,'bar'::text), (3,1,'baz'::text)) v(a, b, c);
+(1 row)
+
+create or replace view agg_view1 as
+ select aggfns(a,a,c order by b)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c);
+select * from agg_view1;
+ aggfns
+------------------------------------------------
+ {"(3,3,baz)","(2,2,bar)","(1,1,foo)","(0,0,)"}
+(1 row)
+
+select pg_get_viewdef('agg_view1'::regclass);
+ pg_get_viewdef
+---------------------------------------------------------------------------------------------------------------------
+ SELECT aggfns(v.a, v.a, v.c ORDER BY v.b) AS aggfns +
+ FROM ( VALUES (1,3,'foo'::text), (0,NULL::integer,NULL::text), (2,2,'bar'::text), (3,1,'baz'::text)) v(a, b, c);
+(1 row)
+
+create or replace view agg_view1 as
+ select aggfns(a,b,c order by c using ~<~)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c);
+select * from agg_view1;
+ aggfns
+-----------------------------------------------
+ {"(2,2,bar)","(3,1,baz)","(1,3,foo)","(0,,)"}
+(1 row)
+
+select pg_get_viewdef('agg_view1'::regclass);
+ pg_get_viewdef
+---------------------------------------------------------------------------------------------------------------------
+ SELECT aggfns(v.a, v.b, v.c ORDER BY v.c USING ~<~ NULLS LAST) AS aggfns +
+ FROM ( VALUES (1,3,'foo'::text), (0,NULL::integer,NULL::text), (2,2,'bar'::text), (3,1,'baz'::text)) v(a, b, c);
+(1 row)
+
+create or replace view agg_view1 as
+ select aggfns(distinct a,b,c order by a,c using ~<~,b)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,2) i;
+select * from agg_view1;
+ aggfns
+-----------------------------------------------
+ {"(0,,)","(1,3,foo)","(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+select pg_get_viewdef('agg_view1'::regclass);
+ pg_get_viewdef
+---------------------------------------------------------------------------------------------------------------------
+ SELECT aggfns(DISTINCT v.a, v.b, v.c ORDER BY v.a, v.c USING ~<~ NULLS LAST, v.b) AS aggfns +
+ FROM ( VALUES (1,3,'foo'::text), (0,NULL::integer,NULL::text), (2,2,'bar'::text), (3,1,'baz'::text)) v(a, b, c),+
+ generate_series(1, 2) i(i);
+(1 row)
+
+drop view agg_view1;
+-- incorrect DISTINCT usage errors
+select aggfns(distinct a,b,c order by i)
+ from (values (1,1,'foo')) v(a,b,c), generate_series(1,2) i;
+ERROR: in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list
+LINE 1: select aggfns(distinct a,b,c order by i)
+ ^
+select aggfns(distinct a,b,c order by a,b+1)
+ from (values (1,1,'foo')) v(a,b,c), generate_series(1,2) i;
+ERROR: in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list
+LINE 1: select aggfns(distinct a,b,c order by a,b+1)
+ ^
+select aggfns(distinct a,b,c order by a,b,i,c)
+ from (values (1,1,'foo')) v(a,b,c), generate_series(1,2) i;
+ERROR: in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list
+LINE 1: select aggfns(distinct a,b,c order by a,b,i,c)
+ ^
+select aggfns(distinct a,a,c order by a,b)
+ from (values (1,1,'foo')) v(a,b,c), generate_series(1,2) i;
+ERROR: in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list
+LINE 1: select aggfns(distinct a,a,c order by a,b)
+ ^
+-- string_agg tests
+select string_agg(a,',') from (values('aaaa'),('bbbb'),('cccc')) g(a);
+ string_agg
+----------------
+ aaaa,bbbb,cccc
+(1 row)
+
+select string_agg(a,',') from (values('aaaa'),(null),('bbbb'),('cccc')) g(a);
+ string_agg
+----------------
+ aaaa,bbbb,cccc
+(1 row)
+
+select string_agg(a,'AB') from (values(null),(null),('bbbb'),('cccc')) g(a);
+ string_agg
+------------
+ bbbbABcccc
+(1 row)
+
+select string_agg(a,',') from (values(null),(null)) g(a);
+ string_agg
+------------
+
+(1 row)
+
+-- check some implicit casting cases, as per bug #5564
+select string_agg(distinct f1, ',' order by f1) from varchar_tbl; -- ok
+ string_agg
+------------
+ a,ab,abcd
+(1 row)
+
+select string_agg(distinct f1::text, ',' order by f1) from varchar_tbl; -- not ok
+ERROR: in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list
+LINE 1: select string_agg(distinct f1::text, ',' order by f1) from v...
+ ^
+select string_agg(distinct f1, ',' order by f1::text) from varchar_tbl; -- not ok
+ERROR: in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list
+LINE 1: select string_agg(distinct f1, ',' order by f1::text) from v...
+ ^
+select string_agg(distinct f1::text, ',' order by f1::text) from varchar_tbl; -- ok
+ string_agg
+------------
+ a,ab,abcd
+(1 row)
+
+-- string_agg bytea tests
+create table bytea_test_table(v bytea);
+select string_agg(v, '') from bytea_test_table;
+ string_agg
+------------
+
+(1 row)
+
+insert into bytea_test_table values(decode('ff','hex'));
+select string_agg(v, '') from bytea_test_table;
+ string_agg
+------------
+ \xff
+(1 row)
+
+insert into bytea_test_table values(decode('aa','hex'));
+select string_agg(v, '') from bytea_test_table;
+ string_agg
+------------
+ \xffaa
+(1 row)
+
+select string_agg(v, NULL) from bytea_test_table;
+ string_agg
+------------
+ \xffaa
+(1 row)
+
+select string_agg(v, decode('ee', 'hex')) from bytea_test_table;
+ string_agg
+------------
+ \xffeeaa
+(1 row)
+
+drop table bytea_test_table;
+-- FILTER tests
+select min(unique1) filter (where unique1 > 100) from tenk1;
+ min
+-----
+ 101
+(1 row)
+
+select ten, sum(distinct four) filter (where four::text ~ '123') from onek a
+group by ten;
+ ten | sum
+-----+-----
+ 0 |
+ 1 |
+ 2 |
+ 3 |
+ 4 |
+ 5 |
+ 6 |
+ 7 |
+ 8 |
+ 9 |
+(10 rows)
+
+select ten, sum(distinct four) filter (where four > 10) from onek a
+group by ten
+having exists (select 1 from onek b where sum(distinct a.four) = b.four);
+ ten | sum
+-----+-----
+ 0 |
+ 2 |
+ 4 |
+ 6 |
+ 8 |
+(5 rows)
+
+select max(foo COLLATE "C") filter (where (bar collate "POSIX") > '0')
+from (values ('a', 'b')) AS v(foo,bar);
+ max
+-----
+ a
+(1 row)
+
+-- outer reference in FILTER (PostgreSQL extension)
+select (select count(*)
+ from (values (1)) t0(inner_c))
+from (values (2),(3)) t1(outer_c); -- inner query is aggregation query
+ count
+-------
+ 1
+ 1
+(2 rows)
+
+select (select count(*) filter (where outer_c <> 0)
+ from (values (1)) t0(inner_c))
+from (values (2),(3)) t1(outer_c); -- outer query is aggregation query
+ count
+-------
+ 2
+(1 row)
+
+select (select count(inner_c) filter (where outer_c <> 0)
+ from (values (1)) t0(inner_c))
+from (values (2),(3)) t1(outer_c); -- inner query is aggregation query
+ count
+-------
+ 1
+ 1
+(2 rows)
+
+select
+ (select max((select i.unique2 from tenk1 i where i.unique1 = o.unique1))
+ filter (where o.unique1 < 10))
+from tenk1 o; -- outer query is aggregation query
+ max
+------
+ 9998
+(1 row)
+
+-- subquery in FILTER clause (PostgreSQL extension)
+select sum(unique1) FILTER (WHERE
+ unique1 IN (SELECT unique1 FROM onek where unique1 < 100)) FROM tenk1;
+ sum
+------
+ 4950
+(1 row)
+
+-- exercise lots of aggregate parts with FILTER
+select aggfns(distinct a,b,c order by a,c using ~<~,b) filter (where a > 1)
+ from (values (1,3,'foo'),(0,null,null),(2,2,'bar'),(3,1,'baz')) v(a,b,c),
+ generate_series(1,2) i;
+ aggfns
+---------------------------
+ {"(2,2,bar)","(3,1,baz)"}
+(1 row)
+
+-- variadic aggregates
+select least_agg(q1,q2) from int8_tbl;
+ least_agg
+-------------------
+ -4567890123456789
+(1 row)
+
+select least_agg(variadic array[q1,q2]) from int8_tbl;
+ least_agg
+-------------------
+ -4567890123456789
+(1 row)
+