如何用聯合查詢替換子查詢？

Question

下面給出的是一個正在運行的查詢。我想用直接聯合查詢替換所有子查詢。請建議我一個解決方案。

SELECT 
    id, 
    startTime, 
    endTime, 
    drawingTime, 
    result, 
    wpAmount, 
    lpAmount, 
    prize, 
    cntWinTickets, 
    cntLoosTickets 
FROM (SELECT 
    i.id   AS id, 
    i.start_time AS startTime, 
    i.end_time  AS endTime, 
    i.drawing_time AS drawingTime, 
    i.result  AS result, 
    SUM(t.amount) AS wpAmount, 
    SUM(t.prize) AS prize, 
    COUNT(t.id) AS cntWinTickets 
     FROM issues i 
    LEFT JOIN orders o 
     ON o.issue_id = i.id 
    LEFT JOIN tickets t 
     ON t.order_id = o.id 
     AND t.has_prize = 1 
     GROUP BY i.id) AS A 
    INNER JOIN (SELECT 
     i.id   AS lid, 
     SUM(t.amount) AS lpAmount, 
     COUNT(t.id) AS cntLoosTickets 
      FROM issues i 
     LEFT JOIN orders o 
      ON o.issue_id = i.id 
     LEFT JOIN tickets t 
      ON (t.order_id = o.id 
       AND (t.has_prize = 0 
       OR t.has_prize IS NULL)) 
      GROUP BY i.id) AS B 
    ON A.id = B.lid 

Answer 1

這是一個解決方案，在SUM運算符中有一個奇特的交叉乘積。我認爲最好不要這樣做，但它很有趣！

SELECT i.id AS id, 
     i.start_time AS startTime, 
     i.end_time AS endTime, 
     i.drawing_time AS drawingTime, 
     i.result AS result, 
     SUM(t.amount*COALESCE(t.has_prize,0)) AS wpAmount, 
     SUM(t.prize*COALESCE(t.has_prize,0)) AS prize, 
     COUNT(case when t.has_prize=1 then t.id end) AS cntWinTickets, 
     SUM(t.amount*(1-COALESCE(t.has_prize,0))) AS lpAmount, 
     COUNT(case when COALESCE(t.has_prize,0)=0 then t.id end) AS cntLoosTickets 
FROM issues i 
LEFT JOIN orders o ON o.issue_id = i.id 
LEFT JOIN tickets t ON t.order_id = o.id AND t.has_prize in (null,0,1) 
GROUP BY i.id 

Answer 2

嘗試：

SELECT i.id AS id, 
     i.start_time AS startTime, 
     i.end_time AS endTime, 
     i.drawing_time AS drawingTime, 
     i.result, 
     SUM(case when t.has_prize=1 then t.amount end) AS wpAmount, 
     SUM(case when t.has_prize=1 then t.prize end) AS prize, 
     COUNT(case when t.has_prize=1 then t.id end) AS cntWinTickets, 
     SUM(case when coalesce(t.has_prize,0)=0 then t.amount end) AS lpAmount, 
     COUNT(case when coalesce(t.has_prize,0)=0 then t.id end) AS cntLoosTickets 
FROM issues i 
LEFT JOIN orders o ON o.issue_id = i.id 
LEFT JOIN tickets t ON t.order_id = o.id AND t.has_prize in (null,0,1) 
GROUP BY i.id 

Answer 3

這裏是如何結合這

SELECT 
    i.id   AS id, 
    i.start_time AS startTime, 
    i.end_time  AS endTime, 
    i.drawing_time AS drawingTime, 
    i.result  AS result, 
    SUM(IF t.has_prize = 1,t.amount,0) AS wpAmount, 
    SUM(IF t.has_prize = 1,t.prize,0) AS prize, 
    COUNT(IF t.has_prize = 1,t.id,0) AS cntWinTickets, 
    SUM(IF t.has_prize = 0,t.amount,0) AS lpAmount, 
    COUNT(IF t.has_prize = 0,1,0) AS cntLoosTickets 
FROM issues i 
    LEFT JOIN orders o ON o.issue_id = i.id 
    LEFT JOIN tickets t ON t.order_id = o.id 
GROUP BY i.id 

IF t.has_prize = 1,t.amount,0這意味着如果t.has_prize = 1不是採取t.amount別人拿0。備用是馬克使用的CASE。