cardinality
Description
Returns the number of elements in an array. The result type is INT. If the input parameter is NULL, the result is also NULL. Null elements are counted in the length.
It is the alias of array_length().
This function is supported from v3.0 onwards.
Syntax
INT cardinality(any_array)
Parameters
any_array
: the ARRAY value from which you want to retrieve the number of elements.
Return value
Returns an INT value.
Examples
mysql> select cardinality([1,2,3]);
+-----------------------+
| cardinality([1,2,3]) |
+-----------------------+
| 3 |
+-----------------------+
1 row in set (0.00 sec)
mysql> select cardinality([1,2,3,null]);
+------------------------------+
| cardinality([1, 2, 3, NULL]) |
+------------------------------+
| 4 |
+------------------------------+
mysql> select cardinality([[1,2], [3,4]]);
+-----------------------------+
| cardinality([[1,2],[3,4]]) |
+-----------------------------+
| 2 |
+-----------------------------+
1 row in set (0.01 sec)
keyword
CARDINALITY, ARRAY_LENGTH, ARRAY