The result of a bitwise AND between 7 and 9 is 1

     
mysql>
mysql> SELECT 9&7;
+-----+
| 9&7 |
+-----+
|   1 |
+-----+
1 row in set (0.00 sec)

1.	UPDATE statement moves each bit to the left one position:
2.	left shift operator
3.	The >> is the right shift operator
4.	Bitwise operators
5.	Bit Operators
6.	Bit operation
7.	Bit or
8.	Left shift
9.	Left shift 3
10.	Shifting beyond 64 bits, or with a negative number, just returns 0.
11.	Move the binary value 11 three bits to the left.
12.	Apply several binary operators to the columns of the MATCHES table.

The result of a bitwise AND between 7 and 9 is 1 : Bit « Function « SQL / MySQL