CHAR() returns a string consisting of the characters given by the code values of those integers : CHAR « String Functions « MySQL Tutorial

1. MySQL Tutorial
2. String Functions
3. CHAR

CHAR(N,... [USING charset_name])

CHAR() interprets each argument N as an integer.

NULL values are skipped.

By default, CHAR() returns a binary string.

mysql>
mysql> SELECT CHAR(7,2,3,4,5);
+-----------------+
| CHAR(7,2,3,4,5) |
+-----------------+
|                 |
+-----------------+
1 row in set (0.00 sec)