Determines whether an input expression is a valid datetime value.
isdate(character_expression)
is a character-type variable, constant expression, or column name.
Determines if the string 12/21/2005 is a valid datetime value:
select isdate('12/21/2005')
Determines if stor_id and date in the sales table are valid datetime values:
select isdate(stor_id), isdate(date) from sales
---- ---- 0 1
store_id is not a valid datetime value, but date is.
Returns 1 if the expression is a valid datetime value; returns 0 if it is not. Returns 0 for NULL input.
