SytelineMaster

I think this is one of the FAQ question for T-SQL programmer, and here is some quick sample 

Last Day of Previous Month

SELECT DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0)) 

Last Day of Current Month

SELECT DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE())+1,0))

Last Day of Next Month

SELECT DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE())+2,0))

Show name of the month:

select datename (mm, date_field)

Or if you want to only show the first three letters of the month:

select left(datename (mm, date_field), 3)