ISDATE
Returns 1 if the expression is a valid date, time, or datetime value; otherwise, 0. ISDATE returns 0 if the expression is a datetime2 value.
Syntax
ISDATE ( expression )
Arguments
expression
Is a character string or expression that can be converted to a character string. The expression must be less than 4,000 characters. Date and time data types, except datetime and smalldatetime, are not allowed as the argument for ISDATE.
Return types
int
Example
IF ISDATE('2017-04-24 11:25:56.342') = 1 SELECT 'true' ELSE SELECT 'false';