MySQL 使用 max(date) 和 sum 獲取 val

Question

這是我的問題。 我有一個包含以下列的表格：

player_id | win_amount | loss_amount | datetime

每條記錄都包含玩家的 id、輸贏金額（另一個字段變為 0）和日期時間。 我想要一個 MySQL 查詢來獲得以下信息：

• player_id
• sum(win_amount) - sum(loss_amount)該玩家的sum(win_amount) - sum(loss_amount)
• 有非零loss_amount最后日期loss_amount
• 前一個日期時間的loss_amount

Answer 1

嘗試以下查詢，利用GROUP BY 、一些聚合函數和相關子查詢。 將table替換為您的實際表名：

SELECT 
    t1.player_id,
    SUM(t1.win_amount) - SUM(t1.loss_amount) AS net_win_amount,
    MAX(IF(t1.loss_amount > 0,
        t1.datetime,
        NULL)) AS last_loss_datetime,
    (SELECT 
            t2.loss_amount
        FROM
            `table` AS t2
        WHERE
            t2.player_id = t1.player_id
                AND t2.loss_amount > 0
        ORDER BY t2.datetime DESC
        LIMIT 0 , 1) AS last_loss_amount
FROM
    `table` AS t1
GROUP BY t1.player_id