sql中也有强转,平常都是在程序中强转。在sql中强转一下可能会更快。来看一下。
CASE
WHEN datediff(
dd,
CAST (T.ZZSCRQ1 AS DATE),
CAST (T.ZZSCRQ2 AS DATE)
) > 0 THEN
CAST (T.ZZSCRQ1 AS DATE)
ELSE
CAST (T.ZZSCRQ2 AS DATE)
END
语法格式是这样 CASE WHEN 条件 then 取A else 取B end 。
CAST 代表强转。