Question

我的两个表如下：

Table 1 : Transaction
TRANS_ID (primary key), TRANS_DATE, TRANS_STATUS, USER_ID (Foreign_Key)

状态更改时将重复相同的user_id

Table 2 : Users
USER_ID (Primary_Key), USER_NAME, USER_DOB, OTHER_INFO

我想获取用户信息以及上次交易状态。

我熟悉以下查询。

SELECT MAX(Transaction.TRANS_DATE),Transaction.TRANS_STATUS, Users.USER_NAME, Users.USER_DOB
FROM Users
INNER_JOIN Transaction ON Transaction.USER_ID = Users.USER_ID 
WHERE Transaction.USER_ID = @UserID

我将UserID与Parameter.AddWithValue一起传递。不幸的是，此方法不会为TRANS_STATUS返回MAX(TRANS_DATE)。它确实返回MAX(TRANS_DATE)，但是TRANS_STATUS是第一个出现的记录，而不是与STATUS记录相对应的MAX(TRANS_DATE)。

请让我知道如何获得TRANS_STATUS的{{1}}。我更喜欢使用MAX(TRANS_DATE)，但建议值得赞赏。

我仍然无法上班。

这是我的表脚本。

INNER JOIN

Answer 1

您可以在子查询上使用连接，最长为TRANS_DATE

    select t.max_trans, t.USER_NAME, t.USER_DOB
    from Transaction 
    INNER JOIN 
    (
        SELECT MAX(Transaction.TRANS_DATE) max_trans, 
             Transaction.USER_ID, Users.USER_NAME, Users.USER_DOB
        FROM Users
        INNER_JOIN Transaction ON Transaction.USER_ID = Users.USER_ID 
        WHERE Transaction.USER_ID = @UserID
    ) t on Transaction.USER_ID = t.USER_ID and t.max_trans = Transaction.TRANS_DATE

Answer 2

如果我理解正确，这可能对您有用

SELECT A.USER_ID AS USER_ID, A.TRANS_DATE AS TRANS_DATE, TRANS_STATUS, USER_NAME, USER_DOB
FROM
(SELECT USER_ID, MAX(TRANS_DATE) AS TRANS_DATE FROM TRANSACTION
GROUP BY USER_ID) A
INNER JOIN
(SELECT USER_ID, TRANS_DATE, TRANS_STATUS FROM TRANSACTION) B
ON A.USER_ID = B.USER_ID
AND A.TRANS_DATE=B.TRANS_DATE
INNER JOIN USERS U
ON A.USER_ID=U.USER_ID;

Answer 3

SELECT Users.USER_NAME, Users.USER_DOB
FROM Users usr INNER JOIN(
    SELECT Transaction.TRANS_STATUS, MAX(Transaction.TRANS_DATE)
    FROM Transaction GROUP BY Transaction.TRANS_STATUS) trs ON trs.USER_ID=usr.USER_ID

Answer 4

您可以使用LAST_VALUE函数

SELECT Top 1 
      u.User_ID
     ,u.user_name
     ,u.user_dob
     ,u.other_info
    ,LAST_VALUE(t.Trans_Date) OVER (PARTITION BY t.user_id ORDER BY 
              t.Trans_Date RANGE BETWEEN UNBOUNDED PRECEDING AND
            UNBOUNDED FOLLOWING) AS Max_Tran_Date
    ,LAST_VALUE(t.trans_status) OVER (PARTITION BY t.user_id ORDER BY 
              t.Trans_Date RANGE BETWEEN UNBOUNDED PRECEDING AND
            UNBOUNDED FOLLOWING) as Last_Status
FROM #Users as u
INNER JOIN #Transaction as t ON t.user_id = u.user_id
WHERE u.User_ID = @UserID

如何在MySQL中获得对应于MAX（DATE）的FIELD？

4 个答案: