MSSQL - Convert, Substring

select substring(convert(char(10), login_date, 120),1,4) as login_year, count(*) as cnt

 

날짜변환 : 2017-03-01 00:00:00 이런 형태로 변경할때.

ISNULL(convert(varchar(10), reg_date, 120)+' '+convert(varchar(8), reg_date, 108), '0000-00-00 00:00:00') as regdate,

 

MSDN : http://msdn.microsoft.com/ko-kr/library/ms187928.aspx