二つのテーブル

Question

から二つの異なる列の和の差を計算する私は、3つの異なるキャッシャーとして名前のテーブル、販売、払い戻しを持って

レジテーブルはあります

cashierID/cashier_name

SALES表があります。

salesID/cashierID/amountReceived

の

返金テーブルがあります。

refundsID/cashierID/amountRefunded

私はレジ係の総量がそれぞれamountReceivedとamountRefunded列を経由して販売して払い戻しから受信し、表示します。そのためのmysql構文がありますか？どうもありがとう！

Answer 1

SELECT c.cashier_name AS cashier, 
    COALESCE(salesByCashier.totalSales, 0) AS sales, 
    COALESCE(refundsByCashier.totalRefunded, 0) AS refunds, 
    COALESCE(salesByCashier.totalSales, 0) - 
     COALESCE(refundsByCashier.totalRefunded, 0 ) AS total 
FROM 
    cashier c 
LEFT JOIN 
    (SELECT s.cashierID AS cashierID, SUM(amountReceived) AS totalSales 
    FROM sales s 
    GROUP BY s.cashierID) salesByCashier 
ON c.cashierID = salesByCashier.cashierID 
LEFT JOIN 
    (SELECT r.cashierID AS cashierID, SUM(amountRefunded) AS totalRefunded 
    FROM refunds r 
    GROUP BY r.cashierID) refundsByCashier 
ON c.cashierID = refundsByCashier.cashierID 

Answer 2

select 
    c.cashierID, 
    c.cashier_name, 
    sum(s.amountReceived) as totalReceived, 
    sum(r.amountRefunded) as totalRefunded 
from CASHIER c 
left join SALES s on s.cashierID = c.cashierID 
left join REFUNDS r on r.cashierID = c.cashierID 
group by 1,2