Subtract two dates in SQL and get days of the result

Question

Select I.Fee
From Item I
WHERE GETDATE() - I.DateCreated < 365 days

How can I subtract two days? Result should be days. Ex: 365 days. 500 days.. etc...

Answer 1

Use DATEDIFF

Select I.Fee
From Item I
WHERE  DATEDIFF(day, GETDATE(), I.DateCreated) < 365

Answer 2

use DATE_DIFF

Select I.Fee
From   Item I
WHERE  DATEDIFF(day, GETDATE(), I.DateCreated)  < 365

• DATE_DIFF

Answer 3

EDIT: It seems I was wrong about the performance on the code example. The best performer is whichever snippet runs second in the posted case. This demonstrates what I was trying to explain, and the time differences are not as dramatic:

----------------------------------
--  Monitor time differences
----------------------------------
CREATE CLUSTERED INDEX dtIDX ON #ArbDates (MyDate)
DECLARE @Stopwatch DATETIME 
SET @Stopwatch = GETDATE()
    -- SARGABLE
    SELECT *
    FROM #ArbDates
    WHERE MyDate > DATEADD(DAY, -364, '2010-01-01')


PRINT DATEDIFF(MS, @Stopwatch, GETDATE())
SET @Stopwatch = GETDATE()
    -- NOT SARGABLE
    SELECT *
    FROM #ArbDates
    WHERE DATEDIFF(DAY, MyDate, '2010-01-01') < 365
PRINT DATEDIFF(MS, @Stopwatch, GETDATE())

Excuse me for posting late and my crudely commented example, but I think it important to mention SARG.

SELECT I.Fee
FROM Item I
WHERE  I.DateCreated > DATEADD(DAY, -364, GETDATE())

Although the temp table in the code below has no index, the performance is still enhanced by the fact that a comparison is done between an expression and a value in the table and not an expression that modifies the value in the table and a constant. Hope this is found to be useful.

USE tempdb
GO

IF OBJECT_ID('tempdb.dbo.#ArbDates') IS NOT NULL DROP TABLE #ArbDates
DECLARE @Stopwatch DATETIME 

----------------------------------
--  Build test data: 100000 rows
----------------------------------
;WITH Base10 (n) AS
(
    SELECT 1 UNION ALL  SELECT 1 UNION ALL  SELECT 1 UNION ALL
    SELECT 1 UNION ALL  SELECT 1 UNION ALL  SELECT 1 UNION ALL
    SELECT 1 UNION ALL  SELECT 1 UNION ALL  SELECT 1 UNION ALL
    SELECT 1
)
,Base100000 (n) AS
(
    SELECT 1
    FROM Base10 T1, Base10 T3, Base10 T4, Base10 T5, Base10 T6
)
SELECT MyDate = CAST(RAND(CHECKSUM(NEWID()))*3653.0+36524.0 AS DATETIME) 
INTO #ArbDates 
FROM Base100000

----------------------------------
--  Monitor time differences
----------------------------------
SET @Stopwatch = GETDATE()

    -- NOT SARGABLE
    SELECT *
    FROM #ArbDates
    WHERE DATEDIFF(DAY, MyDate, '2010-01-01') < 365

PRINT DATEDIFF(MS, @Stopwatch, GETDATE())
SET @Stopwatch = GETDATE()

    -- SARGABLE
    SELECT *
    FROM #ArbDates
    WHERE MyDate > DATEADD(DAY, -364, '2010-01-01')

PRINT DATEDIFF(MS, @Stopwatch, GETDATE())

Answer 4

SELECT DATEDIFF(day,'2014-06-05','2014-08-05') AS DiffDate

diffdate is column name.

result:

DiffDate

23

Answer 5

How about

Select I.Fee
From Item I
WHERE  (days(GETDATE()) - days(I.DateCreated) < 365)

Answer 6

SELECT (to_date('02-JAN-2013') - to_date('02-JAN-2012')) days_between
FROM dual
/