NULLABLE

nullable

description

tip

For developer debugging only, do not call this function manually in the production environment.

Syntax

T nullable(T expr)

Converts expr to nullable, or to itself if expr is already nullable.

example

mysql> select k1, nullable(k1), nullable(1) from test_nullable_functions order by k1;
+------+--------------+-------------+
| k1   | nullable(k1) | nullable(1) |
+------+--------------+-------------+
| NULL |         NULL |           1 |
|    1 |            1 |           1 |
|    2 |            2 |           1 |
|    3 |            3 |           1 |
|    4 |            4 |           1 |
+------+--------------+-------------+

keywords

nullable