SQL SERVER DATETIME应用

PRINT '上周的第一天:'+CONVERT(NVARCHAR(20),DATEADD(WEEK, DATEDIFF(WEEK, 0, GETDATE())-1, 0),120);

PRINT '本周的第一天:'+CONVERT(NVARCHAR(20),DATEADD(WEEK, DATEDIFF(WEEK, 0, GETDATE()), 0),120);

PRINT '上月的第一天:'+CONVERT(NVARCHAR(20),DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE())-1, 0),120);

PRINT '本月的第一天:'+CONVERT(NVARCHAR(20),DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()), 0),120);

PRINT '上年的第一天:'+CONVERT(NVARCHAR(20),DATEADD(YEAR, DATEDIFF(YEAR, 0, GETDATE())-1, 0),120);

PRINT '本年的第一天:'+CONVERT(NVARCHAR(20),DATEADD(YEAR, DATEDIFF(YEAR, 0, GETDATE()), 0),120);

How to get first and last day of previous month (with timestamp) in SQL Server