SQL updates data across tables

Updating data across tables is a common operation.

The raw data is as follows:

 

A_dept initial data

 

A_emp initial data

 

Update SQL statements across tables

Statement function. If company in the_emp table is the same as company in a_dept, update deptid in a_emp.

Statement 1: Update e set E. deptid = D. ID from a_dept D inner join a_emp e on D. Company = E. Company

Statement 2: Update a_emp set deptid = D. id from a_dept d Where a_emp.company = D. Company

After the preceding statement is executed, the data in a_dept remains unchanged, and the data in a_emp changes. See