Sql 改变计数函数的输出

我正在创建一个查询，该查询将以230美元的基本成本开始，然后将每个参加课程的人的家长人数乘以55美元（每个家长参加课程的成本）。 然后，它将检查参加会议的人迄今为止支付的金额，并将从刚刚计算的总成本中减去该金额。 我的问题是，我还需要在每行中包含电子邮件，因此我需要查询的

groupbyguestemail

部分。使用此

groupby

行可以使

COUNT（Guest.ID）

始终返回1，即使在多个情况下它应该返回2、3或4

SELECT Registration.ID, Guest.GuestEmail,
    CASE
        WHEN ((COUNT(Guest.ID) * 55) + 230) - SUM(DISTINCT Transaction.AuthorizationAmount) is not null
            THEN ((COUNT(Guest.ID) * 55) + 230) - SUM(DISTINCT  Transaction.AuthorizationAmount)
        WHEN ((COUNT(Guest.ID) * 55) + 230) is not null AND SUM(DISTINCT Transaction.AuthorizationAmount) is null
            THEN ((COUNT(Guest.ID) * 55) + 230)
        WHEN ((COUNT(Guest.ID) * 55) + 230) is null AND SUM(DISTINCT Transaction.AuthorizationAmount) is not null
            THEN - SUM(DISTINCT Transaction.AuthorizationAmount)
        ELSE '0'
    END AS Balance

    FROM Registration 
    LEFT JOIN Transaction ON Registration.ID = Transaction.ID 
    LEFT JOIN Guest ON Registration.ID = Guest.ID 

    WHERE Registration.IsActive = 'True' AND Registration.ID = 111111 AND ConfirmationEmail = 0 AND Guest.IsActive = 'True' AND Registration.ID = Guest.ID
    GROUP BY Registration.ID, Guest.GuestEmail

注册表包含学生信息，而来宾包含家长信息。通过注册和来宾中包含的ID，将每位家长标识为其子女的家长。家长和学生的ID都是相同的号码。 Transaction.AuthorizationAmount是注册人员已支付的金额。每位客人都有单独的一排。返回的电子邮件是存储在来宾表中的家长电子邮件。

---

问题：如何更改查询以使

COUNT（Guest.ID）

返回除1以外的数字？

只是盲目地尝试这一个，不确定此查询将如何执行，但它可能会给您一些想法：

SELECT r.ID, r.balance, g.GuestEmail
FROM Guest g
JOIN (
    SELECT Registration.ID,
    CASE
        WHEN ((COUNT(Guest.ID) * 55) + 230) - SUM(DISTINCT Transaction.AuthorizationAmount) is not null
            THEN ((COUNT(Guest.ID) * 55) + 230) - SUM(DISTINCT  Transaction.AuthorizationAmount)
        WHEN ((COUNT(Guest.ID) * 55) + 230) is not null AND SUM(DISTINCT Transaction.AuthorizationAmount) is null
            THEN ((COUNT(Guest.ID) * 55) + 230)
        WHEN ((COUNT(Guest.ID) * 55) + 230) is null AND SUM(DISTINCT Transaction.AuthorizationAmount) is not null
            THEN - SUM(DISTINCT Transaction.AuthorizationAmount)
        ELSE '0'
    END AS Balance
    FROM Registration 
    LEFT JOIN Transaction ON Registration.ID = Transaction.ID 
    LEFT JOIN Guest ON Registration.ID = Guest.ID 
    WHERE Registration.IsActive = 'True' AND Registration.ID = 111111 AND ConfirmationEmail = 0 AND Guest.IsActive = 'True' AND Registration.ID = Guest.ID
    GROUP BY Registration.ID
) r ON (g.ID = r.ID)
GROUP BY g.GuestEmail

---

如果是我来上课，我带着妈妈和爸爸，我们每个人都坐在哪一张桌子上，你们的db如何确定他们是我的客人？还有，你想返回谁的电子邮件地址？@Dan Bracuk更新了我的问题以回答这些问题，但这里又是：注册是保存学生信息的表格，而来宾保存家长信息。通过注册和来宾中包含的ID，将每位家长标识为其子女的家长。家长和学生的ID都是相同的号码。Transaction.AuthorizationAmount是注册人员已支付的金额。每位客人都有单独的一排。返回的电子邮件是存储在来宾表中的家长电子邮件。如果这些钱属于我，你确定要邮寄给我的来宾吗？是的，我的老板要邮寄给每个人