CARDINALITY function
The CARDINALITY function returns the size of an ARRAY or MAP expression (expr).
This function is useful to find the size or length of an array.
Syntax
cardinality(expr)
Arguments
- expr
-
An ARRAY or MAP expression.
Returns
Returns the size of an array or a map (INTEGER).
The function returns NULL for null input if sizeOfNull is set to
false or enabled is set to true.
Otherwise, the function returns -1 for null input. With the default settings,
the function returns -1 for null input.
Example
The following query calculates the cardinality, or the number of elements, in the given
array. The array ('b', 'd', 'c', 'a') has 4 elements, so the output of this query
would be 4.
SELECT cardinality(array('b', 'd', 'c', 'a')); 4
