Contents
array_upper()
A function returning the upper bound of an requested array dimension
array_upper() is a system function returning the upper bound of the requested array dimension.
array_upper() was added in PostgreSQL 7.4.
Usage
array_upper (anyarray,integer) →integer
Given a particular array (e.g. ['foo','bar','baz']), array_lower() returns the position of the last (highest) element, i.e. the upper array bound:
postgres=# SELECT array_upper(ARRAY['foo', 'bar', 'baz'], 1);
array_upper
-------------
3
(1 row)
The second parameter in the above example references the array dimension - as the example array only has one dimension, this must of course be 1.
It is also possible to specify a different ending point for the array upper bound, e,g.:
postgres=# SELECT array_upper('[0:2]={1,2,3}'::integer[], 1);
array_upper
-------------
2
(1 row)
Change history
- PostgreSQL 7.4
- added (commit fef731d1)
Examples
Basic execution example for array_upper():
postgres=# SELECT array_upper(ARRAY[1,2,3], 1);
array_upper
-------------
3
(1 row)
Using array_upper() with a multi-dimensional array:
postgres=# SELECT array_upper(array[ [1,2,3],[4,5,NULL] ], 2);
array_upper
-------------
3
(1 row)
NULL is returned if an invalid array dimension is provided:
postgres=# SELECT array_upper(ARRAY[1,2,3], 2) IS NULL; ?column? ---------- t (1 row)
References
- PostgreSQL documentation: Array Functions