sql-server-2008-r2 - 在 sql server 2008 中按时间间隔分组

Question

我有一个查询返回每条记录的时间，时间格式就像

“060000”

我想按三组中的记录进行分组：

first group whose time is <=072000 (Right Time)
second group whose time is >072000 and <=074500  (Late Comers)
Third group whose time is >074500       (For Half Day)

Answer 1

使用CASE语句和子查询：

SELECT t1.TimeGroup, COUNT(t1.*)
FROM (SELECT [...],
      CASE 
         WHEN Time <= 072000 THEN 'Right Time'
         WHEN Time BETWEEN 072001 AND 074500 THEN 'Late Comers'
         WHEN Time > 074500 THEN 'For Half Day'
      END AS "TimeGroup"
   FROM [...]) t1
GROUP BY t1.TimeGroup