BIT_OR(expr): Returns the bitwise OR of all bits in expr. : BIT_OR « Math Numeric Functions « MySQL Tutorial

1. MySQL Tutorial
2. Math Numeric Functions
3. BIT_OR

The calculation is performed with 64-bit (BIGINT) precision.

This function returns 0 if there were no matching rows.

mysql>
mysql>
mysql> select BIT_OR(1);
+-----------+
| BIT_OR(1) |
+-----------+
|         1 |
+-----------+
1 row in set (0.00 sec)