ISDATE

Determines whether an input expression is a valid date.

Syntax

ISDATE ( expression )

Arguments

expression

Is an expression to be validated as a date. expression is any expression that returns a varchar data type.

Return Types

int

Remarks

ISDATE returns 1 if the input expression is a valid date; otherwise, it returns 0. This table shows the return values for a selection of examples.

Column value (varchar)	ISDATE return value
NULL	0
Abc	0
100, -100, 100 a, or 100.00	0
.01	0
-100.1234e-123	0
.231e90	0
$100.12345, - $100.12345, or $-1000.123	0
as100 or 1a00	0
1995-10-1,1/20/95,1995-10-1 12:00pm, Feb 7 1995 11:00pm, or 1995-10-1, or 1/23/95	1
13/43/3425 or 1995-10-1a	0
$1000, $100, or $100 a	0

Examples

A. Use ISDATE to check a variable

This example checks the @datestring local variable for valid date data.

DECLARE @datestring varchar(8)
SET @datestring = '12/21/98'
SELECT ISDATE(@datestring)

Here is the result set:

----------- 
1           

B. Use ISDATE to check a column for dates

This example creates the test_dates table and inserts two values. ISDATE is used to determine whether the values in the columns are dates.

USE tempdb
CREATE TABLE test_dates (Col_1 varchar(15), Col_2 datetime)
GO
INSERT INTO test_dates VALUES ('abc', 'July 13, 1998')
GO
SELECT ISDATE(Col_1) AS Col_1, ISDATE(Col_2) AS Col_2 
   FROM test_dates

Here is the result set:

Col_1                     Col_2               
-----------------         --------------------
0                         1                   

See Also

char and varchar

System Functions