巧妙的Sql函数日期处理方法

本月第一天日期

SELECT FirstDayOfCurrentMonth = dateadd(mm,datediff(mm,0,getdate()),0)

SELECT FirstDayOfCurrentMonth = convert(CHAR(8),getdate(),120)+'1'

下月第一天日期

SELECT FirstDayOfNextMonth = dateadd(mm,datediff(mm,0,getdate())+1,0)

本月最后一天日期

SELECT LastDayOfCurrentMonth = dateadd(dd,-1,dateadd(mm,datediff(mm,0,getdate())+1,0))

SELECT LastDayOfCurrentMonth = dateadd(dd,-1,convert(DATETIME,convert(CHAR(8),dateadd(mm,1,getdate()),120)+'1'))

本月天数

SELECT NumberOfDaysOfCurrentMonth =
convert(INT,
dateadd(mm,datediff(mm,0,getdate())+1,0)
-
dateadd(mm,datediff(mm,0,getdate()),0))

SELECT NumberOfDaysOfCurrentMonth = day(dateadd(day,-1,convert(CHAR(8),dateadd(month,1,getdate()),120)+'1'))