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This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
103 lines
2.8 KiB
SQL
103 lines
2.8 KiB
SQL
--
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-- CREATE_AGGREGATE
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--
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-- all functions CREATEd
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CREATE AGGREGATE newavg (
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sfunc = int4_avg_accum, basetype = int4, stype = _int8,
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finalfunc = int8_avg,
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initcond1 = '{0,0}'
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);
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-- test comments
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COMMENT ON AGGREGATE newavg_wrong (int4) IS 'an agg comment';
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COMMENT ON AGGREGATE newavg (int4) IS 'an agg comment';
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COMMENT ON AGGREGATE newavg (int4) IS NULL;
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-- without finalfunc; test obsolete spellings 'sfunc1' etc
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CREATE AGGREGATE newsum (
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sfunc1 = int4pl, basetype = int4, stype1 = int4,
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initcond1 = '0'
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);
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-- zero-argument aggregate
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CREATE AGGREGATE newcnt (*) (
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sfunc = int8inc, stype = int8,
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initcond = '0'
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);
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-- old-style spelling of same
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CREATE AGGREGATE oldcnt (
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sfunc = int8inc, basetype = 'ANY', stype = int8,
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initcond = '0'
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);
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-- aggregate that only cares about null/nonnull input
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CREATE AGGREGATE newcnt ("any") (
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sfunc = int8inc_any, stype = int8,
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initcond = '0'
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);
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COMMENT ON AGGREGATE nosuchagg (*) IS 'should fail';
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COMMENT ON AGGREGATE newcnt (*) IS 'an agg(*) comment';
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COMMENT ON AGGREGATE newcnt ("any") IS 'an agg(any) comment';
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-- multi-argument aggregate
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create function sum3(int8,int8,int8) returns int8 as
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'select $1 + $2 + $3' language sql strict immutable;
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create aggregate sum2(int8,int8) (
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sfunc = sum3, stype = int8,
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initcond = '0'
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);
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-- multi-argument aggregates sensitive to distinct/order, strict/nonstrict
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create type aggtype as (a integer, b integer, c text);
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create function aggf_trans(aggtype[],integer,integer,text) returns aggtype[]
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as 'select array_append($1,ROW($2,$3,$4)::aggtype)'
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language sql strict immutable;
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create function aggfns_trans(aggtype[],integer,integer,text) returns aggtype[]
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as 'select array_append($1,ROW($2,$3,$4)::aggtype)'
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language sql immutable;
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create aggregate aggfstr(integer,integer,text) (
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sfunc = aggf_trans, stype = aggtype[],
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initcond = '{}'
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);
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create aggregate aggfns(integer,integer,text) (
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sfunc = aggfns_trans, stype = aggtype[], sspace = 10000,
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initcond = '{}'
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);
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-- variadic aggregate
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create function least_accum(anyelement, variadic anyarray)
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returns anyelement language sql as
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'select least($1, min($2[i])) from generate_subscripts($2,1) g(i)';
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create aggregate least_agg(variadic items anyarray) (
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stype = anyelement, sfunc = least_accum
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);
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-- test ordered-set aggs using built-in support functions
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create aggregate my_percentile_disc(float8 ORDER BY anyelement) (
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stype = internal,
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sfunc = ordered_set_transition,
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finalfunc = percentile_disc_final
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);
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create aggregate my_rank(VARIADIC "any" ORDER BY VARIADIC "any") (
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stype = internal,
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sfunc = ordered_set_transition_multi,
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finalfunc = rank_final,
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hypothetical
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);
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alter aggregate my_percentile_disc(float8 ORDER BY anyelement)
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rename to test_percentile_disc;
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alter aggregate my_rank(VARIADIC "any" ORDER BY VARIADIC "any")
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rename to test_rank;
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\da test_*
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