Beam ZetaSQL function call rules

The following rules apply to all functions unless explicitly indicated otherwise in the function description:

• For functions that accept numeric types, if one operand is a floating point operand and the other operand is another numeric type, both operands are converted to FLOAT64 before the function is evaluated.

• If an operand is NULL, the result is NULL, with the exception of the IS operator.

• For functions that are time zone sensitive (as indicated in the function description), the default time zone, UTC, is used if a time zone is not specified.