138 lines
3.4 KiB
SQL
138 lines
3.4 KiB
SQL
--
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-- SELECT_DISTINCT
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--
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--
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-- awk '{print $3;}' onek.data | sort -n | uniq
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--
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SELECT DISTINCT two FROM tmp ORDER BY 1;
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--
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-- awk '{print $5;}' onek.data | sort -n | uniq
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--
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SELECT DISTINCT ten FROM tmp ORDER BY 1;
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--
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-- awk '{print $16;}' onek.data | sort -d | uniq
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--
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SELECT DISTINCT string4 FROM tmp ORDER BY 1;
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--
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-- awk '{print $3,$16,$5;}' onek.data | sort -d | uniq |
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-- sort +0n -1 +1d -2 +2n -3
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--
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SELECT DISTINCT two, string4, ten
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FROM tmp
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ORDER BY two using <, string4 using <, ten using <;
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--
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-- awk '{print $2;}' person.data |
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-- awk '{if(NF!=1){print $2;}else{print;}}' - emp.data |
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-- awk '{if(NF!=1){print $2;}else{print;}}' - student.data |
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-- awk 'BEGIN{FS=" ";}{if(NF!=1){print $5;}else{print;}}' - stud_emp.data |
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-- sort -n -r | uniq
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--
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SELECT DISTINCT p.age FROM person* p ORDER BY age using >;
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--
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-- Check mentioning same column more than once
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--
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EXPLAIN (VERBOSE, COSTS OFF)
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SELECT count(*) FROM
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(SELECT DISTINCT two, four, two FROM tenk1) ss;
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SELECT count(*) FROM
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(SELECT DISTINCT two, four, two FROM tenk1) ss;
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--
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-- Compare results between plans using sorting and plans using hash
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-- aggregation. Force spilling in both cases by setting work_mem low.
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--
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SET work_mem='64kB';
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-- Produce results with sorting.
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SET enable_hashagg=FALSE;
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SET jit_above_cost=0;
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EXPLAIN (costs off)
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SELECT DISTINCT g%1000 FROM generate_series(0,9999) g;
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CREATE TABLE distinct_group_1 AS
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SELECT DISTINCT g%1000 FROM generate_series(0,9999) g;
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SET jit_above_cost TO DEFAULT;
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CREATE TABLE distinct_group_2 AS
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SELECT DISTINCT (g%1000)::text FROM generate_series(0,9999) g;
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SET enable_hashagg=TRUE;
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-- Produce results with hash aggregation.
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SET enable_sort=FALSE;
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SET jit_above_cost=0;
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EXPLAIN (costs off)
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SELECT DISTINCT g%1000 FROM generate_series(0,9999) g;
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CREATE TABLE distinct_hash_1 AS
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SELECT DISTINCT g%1000 FROM generate_series(0,9999) g;
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SET jit_above_cost TO DEFAULT;
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CREATE TABLE distinct_hash_2 AS
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SELECT DISTINCT (g%1000)::text FROM generate_series(0,9999) g;
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SET enable_sort=TRUE;
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SET work_mem TO DEFAULT;
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-- Compare results
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(SELECT * FROM distinct_hash_1 EXCEPT SELECT * FROM distinct_group_1)
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UNION ALL
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(SELECT * FROM distinct_group_1 EXCEPT SELECT * FROM distinct_hash_1);
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(SELECT * FROM distinct_hash_1 EXCEPT SELECT * FROM distinct_group_1)
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UNION ALL
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(SELECT * FROM distinct_group_1 EXCEPT SELECT * FROM distinct_hash_1);
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DROP TABLE distinct_hash_1;
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DROP TABLE distinct_hash_2;
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DROP TABLE distinct_group_1;
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DROP TABLE distinct_group_2;
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--
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-- Also, some tests of IS DISTINCT FROM, which doesn't quite deserve its
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-- very own regression file.
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--
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CREATE TEMP TABLE disttable (f1 integer);
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INSERT INTO DISTTABLE VALUES(1);
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INSERT INTO DISTTABLE VALUES(2);
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INSERT INTO DISTTABLE VALUES(3);
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INSERT INTO DISTTABLE VALUES(NULL);
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-- basic cases
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SELECT f1, f1 IS DISTINCT FROM 2 as "not 2" FROM disttable;
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SELECT f1, f1 IS DISTINCT FROM NULL as "not null" FROM disttable;
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SELECT f1, f1 IS DISTINCT FROM f1 as "false" FROM disttable;
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SELECT f1, f1 IS DISTINCT FROM f1+1 as "not null" FROM disttable;
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-- check that optimizer constant-folds it properly
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SELECT 1 IS DISTINCT FROM 2 as "yes";
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SELECT 2 IS DISTINCT FROM 2 as "no";
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SELECT 2 IS DISTINCT FROM null as "yes";
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SELECT null IS DISTINCT FROM null as "no";
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-- negated form
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SELECT 1 IS NOT DISTINCT FROM 2 as "no";
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SELECT 2 IS NOT DISTINCT FROM 2 as "yes";
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SELECT 2 IS NOT DISTINCT FROM null as "no";
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SELECT null IS NOT DISTINCT FROM null as "yes";
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