• n: The argument n is an expression that resolves to a number.
• return type: double.
  • Returns a NULL value in the following cases:
    • n resolves to a NULL value
    • n does not resolve to a number
  • Returns NaN in the following cases:
    • n resolves to NaN
    • n is less than zero
  • Returns positive infinity if n resolves to positive infinity.
  • Returns negative infinity if n is positive/negative zero.

SELECT ln(n) FROM PHtable