The ISDATE and ISNUMERIC Functions (version 6.5)

ISDATE Function

Checks a variable or column with varchar datatype for valid date format. The function returns 1 when the variable or column contains a valid date, otherwise it returns 0.

In this example, the value 1 is returned:

SELECT ISNUMERIC(zipcode) FROM address
  

ISNUMERIC Function

Checks a variable or column with varchar datatype for valid numeric format. The function returns 1 when the variable or column contains a valid numeric value, otherwise it returns 0.

In this example, the value 1 is returned:

declare @datestring varchar(8)
SELECT @datestring ="12/21/95"
SELECT ISDATE(@datestring)

The following table is a summary of the return values for the ISDATE and ISNUMERIC functions for a selection of examples.