C# 如何比较SQL中的父子数据

我有两个如下所示的SQL表

columns of T1: meterID, parentID, childID  
columns of T2: dataID, meterID, date, amount  

表格样本数据

      T1                            T2
-------------              -------------------------
1 | null |  2  *           1 | 1 | 01,01,2013 | 100  *
1 | null |  3  *           2 | 2 | 01,01,2013 | 60   *
2 |   1  |  4              3 | 3 | 01,01,2013 | 40   *
2 |   1  |  5              4 | 4 | 01,01,2013 | 35
3 |   1  |  6              5 | 5 | 01,01,2013 | 25
3 |   1  |  7              6 | 6 | 01,01,2013 | 15
4 |   2  | null            7 | 7 | 01,01,2013 | 25
5 |   2  | null
6 |   3  | null  
7 |   3  | null  

我想比较一下孩子的金额和父母的金额是否相等

比如,；meter1是meter2和meter3的父级（带*的行）。我想检查100=60+40。
如何使用SQL查询实现这一点

---

对不起，我的英语很差。

你想把孩子的数量加起来，然后和父母比较一下。这需要两个到

t2

表的联接，一个用于父级，另一个用于子级

以下查询假设

t1

没有重复的条目：

select t1.parentId, t1.childId,
       parent.amount as parent_amount,
       SUM(child.amount) as child_amount,
       (case when parent.amount = SUM(child.amount) then 'Match'
             else 'NoMatch'
        end)
from t1 left outer join
     t2 parent
     on t1.parentId = t2.meterid left outer join
     t3 child
     on t1.childId = t2.meterId
group by t1.parent_id, t1.childId, parent.amount

---

您希望汇总子项金额并与父项进行比较。这需要两个到

t2

表的联接，一个用于父级，另一个用于子级

以下查询假设

t1

没有重复的条目：

select t1.parentId, t1.childId,
       parent.amount as parent_amount,
       SUM(child.amount) as child_amount,
       (case when parent.amount = SUM(child.amount) then 'Match'
             else 'NoMatch'
        end)
from t1 left outer join
     t2 parent
     on t1.parentId = t2.meterid left outer join
     t3 child
     on t1.childId = t2.meterId
group by t1.parent_id, t1.childId, parent.amount

---

此请求将子对象分组，并与父对象进行比较

SELECT t1.meterID, 
       CASE WHEN t1.amount = o.SumAmount THEN 'IsMatch' ELSE 'IsNotMatch' END
FROM T2 t1 OUTER APPLY (
                        SELECT SUM(t3.amount) AS SumAmount
                        FROM T1 t2 JOIN T2 t3 ON t2.childID = t3.meterID
                        WHERE t1.meterID = t2.meterID
                        GROUP BY t2.meterID
                        ) o

演示

测试后：可以使用不带GROUPBY子句的查询

SELECT t1.meterID, 
       CASE WHEN t1.amount = o.SumAmount THEN 'IsMatch' ELSE 'IsNotMatch' END
FROM T2 t1 OUTER APPLY (
                        SELECT SUM(t3.amount) AS SumAmount
                        FROM T1 t2 JOIN T2 t3 ON t2.childID = t3.meterID
                        WHERE t1.meterID = t2.meterID
                        ) o

---

此请求将子对象分组，并与父对象进行比较

SELECT t1.meterID, 
       CASE WHEN t1.amount = o.SumAmount THEN 'IsMatch' ELSE 'IsNotMatch' END
FROM T2 t1 OUTER APPLY (
                        SELECT SUM(t3.amount) AS SumAmount
                        FROM T1 t2 JOIN T2 t3 ON t2.childID = t3.meterID
                        WHERE t1.meterID = t2.meterID
                        GROUP BY t2.meterID
                        ) o

演示

测试后：可以使用不带GROUPBY子句的查询

SELECT t1.meterID, 
       CASE WHEN t1.amount = o.SumAmount THEN 'IsMatch' ELSE 'IsNotMatch' END
FROM T2 t1 OUTER APPLY (
                        SELECT SUM(t3.amount) AS SumAmount
                        FROM T1 t2 JOIN T2 t3 ON t2.childID = t3.meterID
                        WHERE t1.meterID = t2.meterID
                        ) o

---

感谢您的回复，您的查询有效，但仅适用于1=2+3。我还要检查2=4+5和3=6+7是否相等。显示米之间关系的图像：@AhmetEmre90，但这在查询中被选中：（2=4+5）=（2，IsMatch）和（3=6+7）=（3，IsMatch）噢，对不起。我的想法完全不同。现在有道理了。再次感谢您的帮助。感谢您的回复，您的查询有效，但仅适用于1=2+3。我还要检查2=4+5和3=6+7是否相等。显示米之间关系的图像：@AhmetEmre90，但这在查询中被选中：（2=4+5）=（2，IsMatch）和（3=6+7）=（3，IsMatch）噢，对不起。我的想法完全不同。现在有道理了。再次感谢你的帮助。