如何使用一个 sql 查询从多个表中删除一行，其中 email id 相同

Question

Table1

 - name
 - phone
 - age
 - email

Table2

 - name
 - phone 
 - age
 - email

I want to delete those data which has the same email in both tables.

Answer 1

SQL Server does not support multi-table deletes, so you need two delete statements (as commented by Larnu).

But it is still a bit tricky since you need to keep track of the emails that were deleted by the first statement so you can use them in the second one. I would recommend a table variable, that you can feed with a output clause:

begin transaction;

declare @deleted_emails table (email nvarchar(100)); 
-- or whatever datatype/length you use

delete from table1
output deleted.email into @deleted_emails
where exists (select 1 from table2 t2 where t2.email = table1.email)

delete from table2
where exists (select 1 from @deleted_emails d where d.email = table2.email);

commit transaction;

Wrapping the code in a transaction makes it atomic (that is, the changes done by both statements are commited or rolled back together).