INSTR (VARCHAR STR, VARCHAR substrate)
Returns the location where substr first appeared in str (counting from 1). If substr does not appear in str, return 0.
mysql> select instr("abc", "b");
+-------------------+
| instr('abc', 'b') |
+-------------------+
| 2 |
+-------------------+
mysql> select instr("abc", "d");
+-------------------+
| instr('abc', 'd') |
+-------------------+
| 0 |
+-------------------+
INSTR