在您的 where 子句中使用 Select Min 和 MAX

Question

我使用了一些 select 语句来驱动结果，但是我有 2 个 select 语句，其中 returns 最短约会时间和最长约会时间。但是，如果最小值和最大值相同，我想从我的 where 子句中删除。

SELECT
  APPOINTMENTS.userid,
  users.LOCATIONID,
  MIN(APPOINTMENTTIME) AS mintime,
  MAX(APPOINTMENTTIME) AS maxtime

FROM appointments
WHERE APPOINTMENTDATE BETWEEN '2017-01-07' AND '2017-01-07'
AND NOT mintime <> maxtime
GROUP BY appointments.USERID,
         users.LOCATIONID,
         appointments.APPOINTMENTDATE

我收到错误 Mintime is not valid。

我确定我需要将它保存在一个新的 sub select 但不确定..

干杯

Answer 1

请尝试

select   
APPOINTMENTS.userid, 
users.LOCATIONID,
min(APPOINTMENTTIME) as mintime, 
max(APPOINTMENTTIME) as maxtime

from appointments
where 
APPOINTMENTDATE between '2017-01-07' and '2017-01-07'

group by 
appointments.USERID,users.LOCATIONID,
appointments.APPOINTMENTDATE
having min(APPOINTMENTTIME)  <> max(APPOINTMENTTIME)

Answer 2

根据 Sql 服务器

试试这个

        SELECT * FROM (
        select   
        APPOINTMENTS.userid, 
        users.LOCATIONID,
        min(APPOINTMENTTIME) as mintime, 
        max(APPOINTMENTTIME) as maxtime
        from appointments
        where 
        APPOINTMENTDATE between '2017-01-07' and '2017-01-08'

        group by 
        appointments.USERID,users.LOCATIONID,
        appointments.APPOINTMENTDATE
        )as t WHERE  mintime <> maxtime

Answer 3

HAVING clause用于聚合函数，例如

HAVING NOT MIN(APPOINTMENTTIME) <> MAX(APPOINTMENTTIME)

不过我不知道你为什么在谓词中使用双重否定，根据你的描述你只需要 <>

HAVING MIN(APPOINTMENTTIME) <> MAX(APPOINTMENTTIME)

在您的 where 子句中使用 Select Min 和 MAX

Use a Select Min and MAx in your where clause

sql

max

min

where-clause