How can I select the first day of a month in SQL?

sql sql-server tsql sql-server-2008 datetime

SELECT DATEADD(month, DATEDIFF(month, 0, @mydate), 0) AS StartOfMonth

sql sql-server tsql sql-server-2008 datetime

In addition to all the above answer, a way based on a function introduced in sql 2012

SELECT DATEFROMPARTS(YEAR(@mydate),MONTH(@mydate),1)

sql sql-server tsql sql-server-2008 datetime

Starting with SQL Server 2012:

SELECT DATEADD(DAY,1,EOMONTH(@mydate,-1))

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