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--
-- LIMIT
-- Check the LIMIT/OFFSET feature of SELECT
--
SELECT ''::text AS two, unique1, unique2, stringu1
FROM onek WHERE unique1 > 50
ORDER BY unique1 LIMIT 2;
SELECT ''::text AS five, unique1, unique2, stringu1
FROM onek WHERE unique1 > 60
ORDER BY unique1 LIMIT 5;
SELECT ''::text AS two, unique1, unique2, stringu1
FROM onek WHERE unique1 > 60 AND unique1 < 63
ORDER BY unique1 LIMIT 5;
SELECT ''::text AS three, unique1, unique2, stringu1
FROM onek WHERE unique1 > 100
ORDER BY unique1 LIMIT 3 OFFSET 20;
SELECT ''::text AS zero, unique1, unique2, stringu1
FROM onek WHERE unique1 < 50
ORDER BY unique1 DESC LIMIT 8 OFFSET 99;
SELECT ''::text AS eleven, unique1, unique2, stringu1
FROM onek WHERE unique1 < 50
ORDER BY unique1 DESC LIMIT 20 OFFSET 39;
SELECT ''::text AS ten, unique1, unique2, stringu1
FROM onek
ORDER BY unique1 OFFSET 990;
SELECT ''::text AS five, unique1, unique2, stringu1
FROM onek
ORDER BY unique1 OFFSET 990 LIMIT 5;
SELECT ''::text AS five, unique1, unique2, stringu1
FROM onek
ORDER BY unique1 LIMIT 5 OFFSET 900;
-- Test null limit and offset. The planner would discard a simple null
-- constant, so to ensure executor is exercised, do this:
select * from int8_tbl limit (case when random() < 0.5 then null::bigint end);
select * from int8_tbl offset (case when random() < 0.5 then null::bigint end);
-- Test assorted cases involving backwards fetch from a LIMIT plan node
begin;
declare c1 cursor for select * from int8_tbl limit 10;
fetch all in c1;
fetch 1 in c1;
fetch backward 1 in c1;
fetch backward all in c1;
fetch backward 1 in c1;
fetch all in c1;
declare c2 cursor for select * from int8_tbl limit 3;
fetch all in c2;
fetch 1 in c2;
fetch backward 1 in c2;
fetch backward all in c2;
fetch backward 1 in c2;
fetch all in c2;
declare c3 cursor for select * from int8_tbl offset 3;
fetch all in c3;
fetch 1 in c3;
fetch backward 1 in c3;
fetch backward all in c3;
fetch backward 1 in c3;
fetch all in c3;
declare c4 cursor for select * from int8_tbl offset 10;
fetch all in c4;
fetch 1 in c4;
fetch backward 1 in c4;
fetch backward all in c4;
fetch backward 1 in c4;
fetch all in c4;
rollback;
-- Stress test for variable LIMIT in conjunction with bounded-heap sorting
SELECT
(SELECT n
FROM (VALUES (1)) AS x,
(SELECT n FROM generate_series(1,10) AS n
ORDER BY n LIMIT 1 OFFSET s-1) AS y) AS z
FROM generate_series(1,10) AS s;
--
-- Test behavior of volatile and set-returning functions in conjunction
-- with ORDER BY and LIMIT.
--
create temp sequence testseq;
explain (verbose, costs off)
select unique1, unique2, nextval('testseq')
from tenk1 order by unique2 limit 10;
select unique1, unique2, nextval('testseq')
from tenk1 order by unique2 limit 10;
select currval('testseq');
explain (verbose, costs off)
select unique1, unique2, nextval('testseq')
from tenk1 order by tenthous limit 10;
select unique1, unique2, nextval('testseq')
from tenk1 order by tenthous limit 10;
select currval('testseq');
explain (verbose, costs off)
select unique1, unique2, generate_series(1,10)
from tenk1 order by unique2 limit 7;
select unique1, unique2, generate_series(1,10)
from tenk1 order by unique2 limit 7;
explain (verbose, costs off)
select unique1, unique2, generate_series(1,10)
from tenk1 order by tenthous limit 7;
select unique1, unique2, generate_series(1,10)
from tenk1 order by tenthous limit 7;
-- use of random() is to keep planner from folding the expressions together
explain (verbose, costs off)
select generate_series(0,2) as s1, generate_series((random()*.1)::int,2) as s2;
select generate_series(0,2) as s1, generate_series((random()*.1)::int,2) as s2;
explain (verbose, costs off)
select generate_series(0,2) as s1, generate_series((random()*.1)::int,2) as s2
order by s2 desc;
select generate_series(0,2) as s1, generate_series((random()*.1)::int,2) as s2
order by s2 desc;
-- test for failure to set all aggregates' aggtranstype
explain (verbose, costs off)
select sum(tenthous) as s1, sum(tenthous) + random()*0 as s2
from tenk1 group by thousand order by thousand limit 3;
select sum(tenthous) as s1, sum(tenthous) + random()*0 as s2
from tenk1 group by thousand order by thousand limit 3;
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