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本文丸趣 TV 小編為大家詳細介紹“MySQL 派生表聯表查詢的方法是什么”，內容詳細，步驟清晰，細節處理妥當，希望這篇“MySQL 派生表聯表查詢的方法是什么”文章能幫助大家解決疑惑，下面跟著丸趣 TV 小編的思路慢慢深入，一起來學習新知識吧。
前情提要：
公司運營的一個商城系統，忽然發現訂單提現功能有問題，有大量的商戶體現金額和訂單金額不一致。于是產生了需求，需要把提現表和供應商表作為一個結果集，連接上訂單表中的訂單金額，通過計算訂單表的金額和體現表商戶提現的金額進行比對，查看商戶是多提現了還是少提現了。
下面記錄我的查詢過程。
查詢過程：
剛開始，第一步我以提現表為主表，查詢出來相關結果。MySQL 語句如下
SELECT count(ysw.supply_id) AS 提現次數 ,ysw.user_id AS 供應商對應的用戶 ID , ysw.supply_id AS 供應商 ID ,SUM(ysw.money) AS 供應商提現總金額 ,
case ysw.pay_type when 10 then 微信 when 20 then 支付寶 else 銀行卡 end as 支付方式 ,
ys.supply_name AS 供應商名稱 ,ys.money AS 供應商余額 ,ys.freez_money AS 供應商凍結金額（已提現金額）FROM yoshop_supply_withdraw AS ysw LEFT JOIN yoshop_supply AS ys ON ysw.supply_id = ys.supply_id
WHERE ysw.create_time 1647446400 AND ysw.apply_status IN (10,20,40) GROUP BY ysw.supply_id
ORDER BY SUM(ysw.money) DESC ;查詢結果如圖是正常的：
接下來，我在左鏈接上訂單表的數據，又添加一個了 left join，金額相關數據發生了變化嚴重不一致, 而且查詢時間明顯延長，MySQL 語句如下
SELECT count(ysw.supply_id) AS 提現次數 ,ysw.user_id AS 供應商對應的用戶 ID , ysw.supply_id AS 供應商 ID ,SUM(ysw.money) AS 供應商提現總金額 ,
case ysw.pay_type when 10 then 微信 when 20 then 支付寶 else 銀行卡 end as 支付方式 ,
ys.supply_name AS 供應商名稱 ,ys.money AS 供應商余額 ,ys.freez_money AS 供應商凍結金額（已提現金額）,SUM(yo.pay_price)
FROM yoshop_supply_withdraw AS ysw LEFT JOIN yoshop_supply AS ys ON ysw.supply_id = ys.supply_id
LEFT JOIN yoshop_order AS yo ON yo.supply_ids =ysw.supply_id
WHERE ysw.create_time 1647446400 AND ysw.apply_status IN (10,20,40) GROUP BY ysw.supply_id
ORDER BY SUM(ysw.money) DESC ;
查詢結果對比圖如下：
經過實踐，我想直接通過左連接查詢到提現表金額和訂單表金額是行不通的。通過網上查資料，以及在技術群里請教，
優化了思路：把提現的統計好, 把訂單的統計好，最后兩個結果集再根據供應商 id 做個鏈接
接下來就是，三步走了，第一步：把提現的統計好，上面第一次嘗試的第一步就是了，第二步：把訂單表的數據統計好。由于使用系統的原因，我直接使用的訂單商品表計算的訂單總金額，這一步也是分三步走的，我直接上代碼：
1. 查詢 yoshop_order 所有進行中，已完成的 訂單 id(order_id);
SELECT order_id FROM yoshop_order WHERE order_status IN (10,30);
2. 查詢沒有退款的訂單 ID
SELECT order_id FROM yoshop_order WHERE order_status IN (10,30) AND order_id NOT IN ( SELECT order_id FROM yoshop_order_refund);
3. 查詢訂單商品表中 所有的訂單金額
SELECT supply_id AS 供應商 ID , SUM(total_pay_price) AS 供應商訂單總金額 FROM yoshop_order_goods WHERE create_time 1647446400 AND order_pay_status = 0 AND order_id IN(SELECT order_id FROM yoshop_order WHERE order_status IN (10,30) AND order_id NOT IN ( SELECT order_id FROM yoshop_order_refund) ) GROUP BY supply_id
ORDER BY SUM(total_pay_price) DESC ;
接下來就是進行把第一步和第二步的查詢結果當作派生表，進行左連接查詢。我在這一步耗費的時間和精力最多。如果你能認真看完，相信一定會有收貨。我在這里把我錯誤的過程也進行了記錄 第一次錯誤拼接：
SELECT * FROM (SELECT count(ysw.supply_id) AS 提現次數 ,ysw.user_id AS 供應商對應的用戶 ID , ysw.supply_id AS supply_id ,SUM(ysw.money) AS 供應商提現總金額 ,
case ysw.pay_type when 10 then 微信 when 20 then 支付寶 else 銀行卡 end as 支付方式 ,
ys.supply_name AS 供應商名稱 ,ys.money AS 供應商余額 ,ys.freez_money AS 供應商凍結金額（已提現金額）FROM yoshop_supply_withdraw AS ysw LEFT JOIN yoshop_supply AS ys ON ysw.supply_id = ys.supply_id
WHERE ysw.create_time 1647446400 AND ysw.apply_status IN (10,20,40) GROUP BY ysw.supply_id
ORDER BY SUM(ysw.money) DESC ) AS t1
union all // left join , 這里是注釋記得刪除
SELECT * FROM -- 這里是錯誤的不應該在查詢
(SELECT supply_id AS supply_id , SUM(total_pay_price) AS total_pay_price FROM yoshop_order_goods WHERE create_time 1647446400 AND order_pay_status = 0 AND order_id IN(SELECT order_id FROM yoshop_order WHERE order_status IN (10,30) AND order_id NOT IN (SELECT order_id FROM yoshop_order_refund) ) GROUP BY supply_id
ORDER BY SUM(total_pay_price) DESC ) AS t2
ON t1.suppply_id = t2.suppply_id通過這一次試錯，明顯看出我把 left join 和 union all 的含義記錯了, 并且在拼接的時候重復使用了 select * from。雖然是試錯了，但也是有收貨的，接下來進行了第二次錯誤的拼接：
SELECT t1. 提現次數 ,t1. 供應商對應的用戶 ID ,t1.supply_id, t1. 支付方式 ,t1. 供應商名稱,t1. 供應商余額, t1. 供應商凍結金額（已提現金額）, t2.total_pay_price FROM (SELECT count(ysw.supply_id) AS 提現次數 ,ysw.user_id AS 供應商對應的用戶 ID , ysw.supply_id AS supply_id ,SUM(ysw.money) AS 供應商提現總金額 ,
case ysw.pay_type when 10 then 微信 when 20 then 支付寶 else 銀行卡 end as 支付方式 ,
ys.supply_name AS 供應商名稱 ,ys.money AS 供應商余額 ,ys.freez_money AS 供應商凍結金額（已提現金額）FROM yoshop_supply_withdraw AS ysw LEFT JOIN yoshop_supply AS ys ON ysw.supply_id = ys.supply_id
WHERE ysw.create_time 1647446400 AND ysw.apply_status IN (10,20,40) GROUP BY ysw.supply_id
ORDER BY SUM(ysw.money) DESC ) AS t1
LEFT JOIN
(SELECT supply_id AS supply_id , SUM(total_pay_price) AS total_pay_price FROM
yoshop_order_goods WHERE create_time 1647446400 AND order_pay_status = 0
AND order_id IN(SELECT order_id FROM yoshop_order WHERE order_status IN (10,30)
AND order_id NOT IN (SELECT order_id FROM yoshop_order_refund) )
GROUP BY supply_id
ORDER BY SUM(total_pay_price) DESC ) AS t2
ON t1.suppply_id = t2.suppply_id通過這兩次錯誤的嘗試，以及根據嘗試過程中 MySQL 給出的錯誤提示，知道自己是在左連接上使用錯誤了，應該在開始查詢出來所有的字段，left join 后不能在使用 select * 最后，回想了一遍自己所學的 left join 的語法，寫出了最后的正確的查詢結果
SELECT t1.supply_id 供應商 ID ,t1.supply_name 供應商名稱 ,t1.user_id 供應商綁定的用戶 ID ,t1.withdrawtime 供應商提現次數 ,t1.supplyallmoney 供應商提現金額 ,t1.payway 供應商提現方式 ,t1.supply_money 供應商賬戶余額 ,t1.supply_free_money 供應商凍結余額（已提現金額）,
t2.total_pay_price 供應商訂單總金額 ,t2.order_id 供應商訂單數量
FROM (SELECT count(ysw.supply_id) AS withdrawtime, ysw.user_id AS user_id, ysw.supply_id AS supply_id , SUM(ysw.money) AS supplyallmoney, ysw.alipay_name AS alipay_name ,ysw.alipay_account AS alipay_account, ysw.audit_time as audit_time , ysw.bank_account AS bank_account, ysw.bank_card AS bank_card, ysw.bank_name AS bank_name,
case ysw.pay_type when 10 then 微信 when 20 then 支付寶 else 銀行卡 end as payway ,
ys.supply_name AS supply_name, ys.money AS supply_money, ys.freez_money AS supply_free_money
FROM yoshop_supply_withdraw AS ysw LEFT JOIN yoshop_supply AS ys ON ysw.supply_id = ys.supply_id
WHERE ysw.create_time 1647446400 AND ysw.apply_status IN (10,20,40) GROUP BY ysw.supply_id
ORDER BY SUM(ysw.money) DESC ) AS t1
LEFT JOIN
(SELECT supply_id AS supply_id , COUNT(order_id) AS order_id, SUM(total_pay_price) AS total_pay_price
FROM yoshop_order_goods WHERE create_time 1647446400 AND order_pay_status = 0
AND order_id IN( SELECT order_id FROM yoshop_order WHERE order_status IN (10,30)
AND order_id NOT IN ( SELECT order_id FROM yoshop_order_refund) )
GROUP BY supply_id
ORDER BY SUM(total_pay_price) DESC ) AS t2
ON t1.supply_id = t2.supply_id正確的結果截圖：
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