Question

我想获取开始时间，但它不应该在开始和结束时间之间（使用另一个表的引用获取）。我已经尝试过，但是我遇到了错误。谁能帮助我呢？

SELECT DISTINCT right(start_time,7) AS st_time
FROM Session_Info
WHERE CourseName = 'Java'
  AND (right(start_time,7) NOT IN BETWEEN
         (SELECT right(start_time,7)
          FROM Session_Info
          WHERE Session_Id IN
              (SELECT Session_Id
               FROM sessions
               WHERE UserId='a')) AND
         (SELECT right(end_time,7)
          FROM Session_Info
          WHERE Session_Id IN
              (SELECT Session_Id
               FROM sessions
               WHERE UserId='a')))

同样重用相同的查询（如从UserId ='a'的会话中选择Session_Id）如何将其存储在变量中？

Answer 1

您可以将代码重写为

SELECT  DISTINCT right(start_time,7) AS st_time
FROM    Session_Info
WHERE   CourseName = 'Java'
        AND Session_ID IN (SELECT Session_ID FROM sessions WHERE UserId = 'a')
        AND NOT (right(start_time,7) BETWEEN right(start_time,7) AND right(end_time,7))

或使用CTE

;WITH mySessionIDs (Session_ID)
(
    SELECT  Session_ID
    FROM    sessions
    WHERE   UserId = 'a'
)
SELECT  DISTINCT right(si.start_time,7) AS st_time
FROM    Session_Info si
        INNER JOIN mySessionIDs
            ON si.Session_ID = mySessionIDs.Session_ID
WHERE   si.CourseName = 'Java'
        AND NOT (right(start_time,7) BETWEEN right(start_time,7) AND right(end_time,7))

选择开始和结束时间之间的开始时间

1 个答案: