【SQL】How to get First and Last day of a month – TSQL

– First Day Previous/Current/Next Months
SELECT      DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) - 1, 0),
            'First Day of Previous Month'
UNION ALL
SELECT      DATEADD(DAY, -(DAY(DATEADD(MONTH, 1, GETDATE())) - 1),
            DATEADD(MONTH, -1, GETDATE())),
            'First Day of Previous Month (2)'
UNION ALL
SELECT      DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()), 0),
            'First Day of Current Month'
UNION ALL
SELECT      DATEADD(DAY, -(DAY(GETDATE()) - 1), GETDATE()),
            'First Day of Current Month (2)'
UNION ALL
SELECT      DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) + 1, 0),
            'First Day of Next Month'
UNION ALL
SELECT      DATEADD(DAY, -(DAY(DATEADD(MONTH, 1, GETDATE())) - 1),
            DATEADD(MONTH, 1, GETDATE())),
            'First Day of Next Month (2)'

Result Set:

                       

———————– ——————————-

2011-04-01 00:00:00.000 First Day of Previous Month

2011-04-01 15:47:36.660 First Day of Previous Month (2)

2011-05-01 00:00:00.000 First Day of Current Month

2011-05-01 15:47:36.660 First Day of Current Month (2)

2011-06-01 00:00:00.000 First Day of Next Month

2011-06-01 15:47:36.660 First Day of Next Month (2)

(6 row(s) affected)

The above queries can be generalized as below:

DECLARE @DURATION INT = 2
SELECT      DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) + @DURATION, 0)
            AS '+2 Months'
 
SET @DURATION = -2
SELECT      DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) + @DURATION, 0)
            AS '-2 Months'

Result Set:

+2 Months

———————–

2011-07-01 00:00:00.000

(1 row(s) affected)

-2 Months

———————–

2011-03-01 00:00:00.000

(1 row(s) affected)

And, to get last day of a month use:

– Last Day Previous/Current/Next Months
SELECT      DATEADD(DAY, -(DAY(GETDATE())), GETDATE()),
            'Last Day of Previous Month'
UNION ALL
SELECT      DATEADD(MILLISECOND, -3,
            DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()), 0)),
            'Last Day of Previous Month (2)'
UNION ALL
SELECT      DATEADD(DAY, -(DAY(DATEADD(MONTH, 1, GETDATE()))),
            DATEADD(MONTH, 1, GETDATE())),
            'Last Day of Current Month'
UNION ALL
SELECT      DATEADD(MILLISECOND, -3,
            DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) + 1, 0)),
            'Last Day of Current Month (2)'
UNION ALL
SELECT      DATEADD(DAY, -(DAY(DATEADD(MONTH,0,GETDATE()))),
            DATEADD(MONTH, 2, GETDATE())),
            'Last Day of Next Month'
UNION ALL
SELECT      DATEADD(SECOND, -1,
            DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) + 2, 0)),
            'Last Day of Next Month (2)'

Result Set:

                       

———————– ——————————

2011-04-30 15:54:35.523 Last Day of Previous Month

2011-04-30 23:59:59.997 Last Day of Previous Month (2)

2011-05-31 15:54:35.523 Last Day of Current Month

2011-05-31 23:59:59.997 Last Day of Current Month (2)

2011-06-30 15:54:35.523 Last Day of Next Month

2011-06-30 23:59:59.000 Last Day of Next Month (2)

(6 row(s) affected)

The above queries can be generalized as below:

DECLARE @DURATION INT = 2
SELECT   DATEADD(MILLISECOND, -3,
         DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) + @DURATION + 1, 0))
         AS '+2 Months'
 
SET @DURATION = -2
SELECT   DATEADD(MILLISECOND, -3,
         DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) + @DURATION + 1, 0))
         AS '-2 Months'

Result Set:

+2 Months

———————–

2011-07-31 23:59:59.997

(1 row(s) affected)

-2 Months

———————–

2011-03-31 23:59:59.997

(1 row(s) affected)

Hope This Helps!