FOREACH

description

Converts an aggregate function for tables into an aggregate function for arrays that aggregates the corresponding array items and returns an array of results. For example, sum_foreach for the arrays [1, 2], [3, 4, 5]and[6, 7]returns the result [10, 13, 5] after adding together the corresponding array items.

Syntax

AGGREGATE_FUNCTION_FOREACH(arg...)

example

mysql [test]>select a , s from db;
+-----------+---------------+
| a         | s             |
+-----------+---------------+
| [1, 2, 3] | ["ab", "123"] |
| [20]      | ["cd"]        |
| [100]     | ["efg"]       |
| NULL      | NULL          |
| [null, 2] | [null, "c"]   |
+-----------+---------------+

mysql [test]>select sum_foreach(a) from db;
+----------------+
| sum_foreach(a) |
+----------------+
| [121, 4, 3]    |
+----------------+

mysql [test]>select count_foreach(s) from db;
+------------------+
| count_foreach(s) |
+------------------+
| [3, 2]           |
+------------------+

mysql [test]>select array_agg_foreach(a) from db;
+-----------------------------------+
| array_agg_foreach(a)              |
+-----------------------------------+
| [[1, 20, 100, null], [2, 2], [3]] |
+-----------------------------------+

mysql [test]>select map_agg_foreach(a,a) from db;
+---------------------------------------+
| map_agg_foreach(a, a)                 |
+---------------------------------------+
| [{1:1, 20:20, 100:100}, {2:2}, {3:3}] |
+---------------------------------------+

keywords

FOREACH