[Mssql] 시간 계산 방법

--덧셈
SELECT DATEADD(YEAR, 1, '20221104')
SELECT DATEADD(MONTH, 1, '20221104')
SELECT DATEADD(DAY, 1, '20221104')
SELECT DATEADD(SECOND, 1, '20221104')

--뺄셈
SELECT DATEADD(YEAR, -1, '20221104')
SELECT DATEADD(MONTH, -1, '20221104')
SELECT DATEADD(DAY, -1, '20221104')
SELECT DATEADD(SECOND, -1, '20221104')

--차이
SELECT DATEDIFF(YEAR, '20221104', '20221105')
SELECT DATEDIFF(MONTH, '20221104', '20221105')
SELECT DATEDIFF(DAY, '20221104', '20221105')
SELECT DATEDIFF(SECOND, '20221104', '20221105')

--특정 년도나 달, 일 추출
SELECT DATEPART(YEAR, '20221104')
SELECT DATEPART(MONTH, '20221104')
SELECT DATEPART(DAY, '20221104')

SELECT YEAR('20221104')
SELECT MONTH('20221104')
SELECT DAY('20221104')