TINYINT sign(DOUBLE x) Returns the sign of x. Negative, zero or positive numbers correspond to -1, 0 or 1 respectively.
mysql> select sign(3); +-----------+ | sign(3.0) | +-----------+ | 1 | +-----------+ mysql> select sign(0); +-----------+ | sign(0.0) | +-----------+ | 0 | mysql> select sign(-10.0); +-------------+ | sign(-10.0) | +-------------+ | -1 | +-------------+ 1 row in set (0.01 sec)
SIGN