MYSQL在group by中有共同的记录

Question

这是我的 table :

user     presenter   price  
------  ------------  --------
84            84      5000
88            84      3000
89            84      4000
89            84      7000

我将按用户 对这个表进行分组并汇总每个用户的总价格，还包括他们的presenter id 的行等于用户
最终结果应该是:

user          total_price  
------    ------------------
84        5000 + 3000 + 4000 + 7000
88        3000
89        4000 + 7000

Answer 1

您可以为此使用UNION ALL:

SELECT user, SUM(price) AS total_price
FROM (
  SELECT user, price
  FROM mytable

  UNION ALL

  SELECT presenter AS user, price
  FROM mytable AS t1
  WHERE presenter <> user AND
        EXISTS (SELECT 1
                FROM mytable AS t2
                WHERE t1.presenter = t2.user)) AS t
GROUP BY user

第二个查询将所有具有 presenter 且也是 user 的记录附加到 user 数据。外部查询仅使用 GROUP BY，以便为每个 user 计算 price 的 SUM。

Demo here