Boolean

Function Name	Description
IS [NOT] DISTINCT FROM	Compares two expressions to determine whether they have the same or different values. NULLs are considered as comparable values.
ISFALSE	Tests whether the input expression is false. If it is, returns a value of true.
IS [NOT] NULL	Determines if an expression is NULL or not NULL. Alias for the function ISNULL/ISNOTNULL.
ISNUMERIC	Determines whether an expression is a valid numeric type (DECIMAL, DOUBLE, INT, BIGINT, VARBINARY).
ISTRUE	Returns TRUE if the input expression evaluates to TRUE.
IS_MEMBER	Returns whether the current user is a member of the specified role.