在SQL Server上你可以使用:

SELECT *
FROM customer c
INNER JOIN purchase p on c.id = p.customer_id
WHERE p.id = (
    SELECT TOP 1 p2.id
    FROM purchase p2
    WHERE p.customer_id = p2.customer_id
    ORDER BY date DESC
)

SQL Server小提琴:http://sqlfiddle.com/#!18/262fd / 2

在MySQL上你可以使用:

SELECT c.name, date
FROM customer c
INNER JOIN purchase p on c.id = p.customer_id
WHERE p.id = (
    SELECT p2.id
    FROM purchase p2
    WHERE p.customer_id = p2.customer_id
    ORDER BY date DESC
    LIMIT 1
)

MySQL小提琴:http://sqlfiddle.com/#!9/202613/7

先不讲代码，逻辑/算法如下:

Go to the transaction table with multiple records for the same client. Select records of clientID and the latestDate of client's activity using group by clientID and max(transactionDate) select clientID, max(transactionDate) as latestDate from transaction group by clientID inner join the transaction table with the outcome from Step 2, then you will have the full records of the transaction table with only each client's latest record. select * from transaction t inner join ( select clientID, max(transactionDate) as latestDate from transaction group by clientID) d on t.clientID = d.clientID and t.transactionDate = d.latestDate) You can use the result from step 3 to join any table you want to get different results.

您也可以尝试使用子选择来完成此操作

SELECT  c.*, p.*
FROM    customer c INNER JOIN
        (
            SELECT  customer_id,
                    MAX(date) MaxDate
            FROM    purchase
            GROUP BY customer_id
        ) MaxDates ON c.id = MaxDates.customer_id INNER JOIN
        purchase p ON   MaxDates.customer_id = p.customer_id
                    AND MaxDates.MaxDate = p.date

选择应加入所有客户和他们的最后购买日期。

表:

Customer => id, name
Purchase => id, customer_id, item_id, date

查询:

SELECT C.id, C.name, P.id, P.date
  FROM customer AS C
  LEFT JOIN purchase AS P ON 
    (
      P.customer_id = C.id 
      AND P.id IN (
        SELECT MAX(PP.id) FROM purchase AS PP GROUP BY PP.customer_id
      )
    )

你也可以指定一些条件到子选择查询

我需要你需要的东西，尽管是在许多年后，我尝试了最流行的两个答案。这些都没有产生预期的结果。这就是我所能提供的…为了清晰起见，我更改了一些名称。

SELECT 
  cc.pk_ID AS pk_Customer_ID, 
  cc.Customer_Name AS Customer_Name, 
  IFNULL(pp.pk_ID, '') AS fk_Purchase_ID,
  IFNULL(pp.fk_Customer_ID, '') AS fk_Customer_ID,
  IFNULL(pp.fk_Item_ID, '') AS fk_Item_ID,
  IFNULL(pp.Purchase_Date, '') AS Purchase_Date
FROM customer cc
LEFT JOIN purchase pp ON (
  SELECT zz.pk_ID 
  FROM purchase zz 
  WHERE cc.pk_ID = zz.fk_Customer_ID 
  ORDER BY zz.Purchase_Date DESC LIMIT 1) = pp.pk_ID
ORDER BY cc.pk_ID;

试试这个，会有帮助的。

我在我的项目中使用了这个。

SELECT 
*
FROM
customer c
OUTER APPLY(SELECT top 1 * FROM purchase pi 
WHERE pi.customer_id = c.Id order by pi.Id desc) AS [LastPurchasePrice]