MySQL Tutorial/Math Numeric Functions/LOG2

LOG2(X) returns the base-2 logarithm of X

If called with two parameters, this function returns the logarithm of X for an arbitrary base B.

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mysql> mysql> SELECT LOG(2,65536); +--------------+ | LOG(2,65536) | +--------------+ | 16 | +--------------+ 1 row in set (0.00 sec) mysql> SELECT LOG(10,100); +-------------+ | LOG(10,100) | +-------------+ | 2 | +-------------+ 1 row in set (0.01 sec) mysql> LOG(B,X) is equivalent to LOG(X) / LOG(B). mysql></source>