Sql server 如何在更新中合并两行并求和一些列？

我使用SQL Server，仅当多行在两个特定列（在我的示例中为Col_01和Col_02）中具有相同的值时，才需要合并多行。 当我合并它们时，我必须对一些列求和（在我的示例中是Col_03和Col_04）

我认为一个例子会更加明确。这是我的桌子：

| ID  | Col_01 | Col_02 | Col_03 | Col_04  |
| 1   | ABC    | DEF    | 2      | 2       | 
| 2   | ABC    | DEF    | 1      | 0       | 
| 3   | DEF    | GHI    | 0      | 2       | 
| 4   | ABC    | GHI    | 1      | 0       | 
| 5   | JKL    | GHI    | 0      | 2       | 

以下是更新后我想要的：

| ID  | Col_01 | Col_02 | Col_03 | Col_04  | 
| 2   | ABC    | DEF    | 3      | 2       | 
| 3   | DEF    | GHI    | 0      | 2       | 
| 4   | ABC    | GHI    | 1      | 0       | 
| 5   | JKL    | GHI    | 0      | 2       | 

我合并了ID 1和ID 2，因为它们具有相同的列01和列02

我试过这样的问题

SELECT MAX(ID), Col_01, Col_02, SUM(Col_03), SUM(Col_04)
FROM Table
GROUP BY Col_01, Col_02

我有合并的行，但我没有合并的行

我不知道如何在

UPDATE

查询中正确使用它，以便合并具有相同（Col_01，Col_02）的行并保留其他行。你能帮我做这个吗？

试试这个：

UPDATE  T SET 
        T.Col_03 = G.Col_03,
        T.Col_04 = G.Col_04
FROM    Table AS T INNER JOIN
        (SELECT   MAX(ID) AS ID, Col_01, Col_02, SUM(Col_03) AS Col_03, SUM(Col_04) AS Col_04
         FROM     Table
         GROUP BY Col_01, Col_02) AS G 
         ON G.ID = T.ID

试试这个：

UPDATE  T SET 
        T.Col_03 = G.Col_03,
        T.Col_04 = G.Col_04
FROM    Table AS T INNER JOIN
        (SELECT   MAX(ID) AS ID, Col_01, Col_02, SUM(Col_03) AS Col_03, SUM(Col_04) AS Col_04
         FROM     Table
         GROUP BY Col_01, Col_02) AS G 
         ON G.ID = T.ID

---

所以您实际上需要从原始表中删除一些行。使用

MERGE

语句：

MERGE Table tgt
USING (SELECT MAX(ID) as ID, Col_01, Col_02, SUM(Col_03) AS Col_03, SUM(Col_04) AS Col_04
       FROM Table
       GROUP BY Col_01, Col_02) src ON tgt.ID = srs.ID
WHEN MATCHED THEN
    UPDATE
    SET Col_03 = src.Col_03, Col_04 = src.Col_04
WHEN NOT MATCHED BY SOURCE THEN
    DELETE

---

所以您实际上需要从原始表中删除一些行。使用

MERGE

语句：

MERGE Table tgt
USING (SELECT MAX(ID) as ID, Col_01, Col_02, SUM(Col_03) AS Col_03, SUM(Col_04) AS Col_04
       FROM Table
       GROUP BY Col_01, Col_02) src ON tgt.ID = srs.ID
WHEN MATCHED THEN
    UPDATE
    SET Col_03 = src.Col_03, Col_04 = src.Col_04
WHEN NOT MATCHED BY SOURCE THEN
    DELETE

---

您可以使用join进行更新。顺便说一句，您需要更新哪个ID？您可以使用join进行更新。顺便问一下，您需要更新哪个ID？