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## log function

The `log` function returns the logarithmic value with the specified base for the given expression.

Syntax:

    double log(n,b)

Semantics:

- n, b: The arguments n and b are expressions that resolve to numbers. The base b can resolve to any positive value except zero and one. n can resolve to any positive value.
- return type: double.
  - Returns a NULL value in the following cases:
    - If either of the arguments resolves to a NULL value
    - If either of the arguments does not resolve to a number
  - Returns positive infinity if either of the arguments resolves to positive infinity.

Example 12-84 log function

    SELECT log(n,b) FROM PHtable

Value of n | Value of b | Output
--- | --- | ---
2 | 2 | 1.0
81 | 3 | 4.0
255 | 5 | 3.442980622208573