Question

我有两个表，我需要比较数据并更新一个表记录。请让我知道如何做到这一点，我试图不使用合并。这是方案

Proj1表 这是第一个需要同步数据的表

ID Text 
1   R1
2   R2
3   R3

Proj2表 这是正在进行数据更新的表

    ID Text Active
    3   R1    1
    4   R3    1
    5   R4    1

在这两个表之间的文本字段上进行比较后，结果应类似于以下内容。我们正在将Proj2中的数据同步到类似于Proj1。

    ID Text Active
    3   R1    1 (Ignore as it exists in both tables)
    4   R3    1 (Ignore as it exists in both tables)
    5   R4    0 (Update to inactive as it does not exist Proj1 table)
    6   R2    1 (Insert as it does not exist in Proj2 table)

Answer 1

merge [Proj2Table] target
using ( select [id], [text] from [Proj1Table] ) source ([id], [text] )
on target.[id] = source.[id]
when not matched by source
then update
set target.[Active] = 0
when not matched by target
then insert
    ([id], [text] )
values( source.[id], source.[text] )

Answer 2

-- update records in table 2 that cannot be found in table 1

update P2
set P2.[Active] = 0
from [Proj2Table] as P2
left join [Proj1TAble] as P1 on P1.[text] = P2.[text]
where P1.[id] is null;

-- update records in table 2 that can be found in table 1
update P2
set P2.[Active] = 1
from [Proj2Table] as P2
join [Proj1TAble] as P1 on P1.[text] = P2.[text];

-- insert missing records from table 1 into table 2 with active bit set
insert into [Proj2Table] ([id] , [text] , [active] )
select [id] , [text] , [active] = 1
from [Proj1Table] as P1
where not exists (select 1 from [Proj2Table] as P2 where P2.[text] = P1.[text])
;

不确定[id]列是否匹配或是否为pk / identity / sequence

Answer 3

如果你真的不能使用MERGE，你可以简单地将其拆分为更新和插入查询：

INSERT INTO @Proj2(Text, Active)
SELECT Text,1 FROM @Proj1 p1
WHERE NOT EXISTS(
    SELECT * 
    FROM @Proj2 p2
    WHERE p2.Text = p1.Text
);

UPDATE
    p2
SET
    p2.Active = CASE WHEN p1.id is null THEN 0 ELSE 1 END
FROM
    @Proj2 p2
LEFT JOIN
    @Proj1 p1
ON
    p2.Text = p1.Text;

这假设您的ID是自动增量。

Thsi与Zak的新答案非常相似，但合并了2个更新查询。

Answer 4

另一种方法是使用光标，如果你真的不想使用MERGE

-declare第一个表上的一个光标并滚动该行，然后对于每一行选择第二个表中相应的行和ac，如果找到/未找到...

虽然不是与性能相关的最佳建议......

比较两个表之间的数据并更新一个表数据

4 个答案: