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Add width_bucket(anyelement, anyarray).

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This provides a convenient method of classifying input values into buckets
that are not necessarily equal-width.  It works on any sortable data type.

The choice of function name is a bit debatable, perhaps, but showing that
there's a relationship to the SQL standard's width_bucket() function seems
more attractive than the other proposals.

Petr Jelinek, reviewed by Pavel Stehule
This commit is contained in:
Tom Lane
2014-09-09 15:34:10 -04:00
parent 220bb39dee
commit e80252d424
7 changed files with 458 additions and 12 deletions
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62
src/test/regress/sql/arrays.sql
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@ -476,3 +476,65 @@ drop table src;
select length(md5((f1[1]).c2)) from dest;
drop table dest;
drop type textandtext;
-- Tests for polymorphic-array form of width_bucket()
-- this exercises the varwidth and float8 code paths
SELECT
op,
width_bucket(op::numeric, ARRAY[1, 3, 5, 10.0]::numeric[]) AS wb_n1,
width_bucket(op::numeric, ARRAY[0, 5.5, 9.99]::numeric[]) AS wb_n2,
width_bucket(op::numeric, ARRAY[-6, -5, 2.0]::numeric[]) AS wb_n3,
width_bucket(op::float8, ARRAY[1, 3, 5, 10.0]::float8[]) AS wb_f1,
width_bucket(op::float8, ARRAY[0, 5.5, 9.99]::float8[]) AS wb_f2,
width_bucket(op::float8, ARRAY[-6, -5, 2.0]::float8[]) AS wb_f3
FROM (VALUES
(-5.2),
(-0.0000000001),
(0.000000000001),
(1),
(1.99999999999999),
(2),
(2.00000000000001),
(3),
(4),
(4.5),
(5),
(5.5),
(6),
(7),
(8),
(9),
(9.99999999999999),
(10),
(10.0000000000001)
) v(op);
-- ensure float8 path handles NaN properly
SELECT
op,
width_bucket(op, ARRAY[1, 3, 9, 'NaN', 'NaN']::float8[]) AS wb
FROM (VALUES
(-5.2::float8),
(4::float8),
(77::float8),
('NaN'::float8)
) v(op);
-- these exercise the generic fixed-width code path
SELECT
op,
width_bucket(op, ARRAY[1, 3, 5, 10]) AS wb_1
FROM generate_series(0,11) as op;
SELECT width_bucket(now(),
array['yesterday', 'today', 'tomorrow']::timestamptz[]);
-- corner cases
SELECT width_bucket(5, ARRAY[3]);
SELECT width_bucket(5, '{}');
-- error cases
SELECT width_bucket('5'::text, ARRAY[3, 4]::integer[]);
SELECT width_bucket(5, ARRAY[3, 4, NULL]);
SELECT width_bucket(5, ARRAY[ARRAY[1, 2], ARRAY[3, 4]]);