+-- 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)
+