比较sql中的2个表 [英] Compare 2 tables in sql

问题描述

我有两张桌子，A1 和 A2.我想比较这两个表.我尝试了内连接，但它没有给出所需的结果.

I have two tables, A1 and A2. I want to compare these two tables. I tried inner join but it doesn't give the required result.

这些是这些表中的数据，

These are the data in these tables,

表 A1

No. Address 
1  abc
1  abc
1  def
1  def

表 A2

No. Address
1    def
1    abc
1    abc
1    def

这两个表只能使用No.列连接.所以如果我使用 INNER JOIN 它会给出 16 行.我不想那样，我只想显示 4 行.这应该是输出:

These two tables can only be joined by using No. column. So if I use INNER JOIN it gives 16 rows. I don't want that, I want only 4 rows to be displayed. This should be the output:

No.   Address   eq
1     abc      #
1     abc      *
1     abc      #
1     abc      #

如果 A1 中的地址等于 A2，则显示最后一列

Last column is displayed if address in A1 is equal to A2

推荐答案

搜索A1表中存在但A2表中不存在的记录:

Search for records that exist in A1 table but not in A2 table:

SELECT * FROM A1 WHERE NOT EXISTS (SELECT * FROM A2 WHERE A2.Id = A1.Id)

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