oracle - 如何在 Oracle 中实现条件更新？

Question

我是 oracle 的新手，我的其中一个 SQL 查询有问题。
有 2 个用户:User1和 User2 :

     Tab1               Tab2
    --------            -------- 
    
    EmpNo               EmpNo
    EmpName             EmpName
    ContactNo           Salary
    Location    

User2 has all privileges in User1.Tab1, and there is no foreign key relationship between the two tables.

The Problem:

I wanted to add a column in tab2 "NameDesignation" And I wanted to insert the value in this column after checking the following condition:

WHEN User1.Tab1.EmpNo = User2.Tab2.EmpNo THEN
   INSERT INTO Tab2 VALUES (&designation)

我真的不知道该怎么做，希望能得到一点帮助。有什么想法吗？

Answer 1

尝试这个:

update user2.tab2.empno t2
set NameDesignation= &designation
where exists (select ''
              from user1.tab1 t1
              where t1.empno=t2.empno)

(声明更新以匹配编辑的问题)