update query with join on two tables

Question

I have customer and address tables.

Query:

SELECT *
FROM addresses a,
     customers b
WHERE a.id = b.id

Answer 1

Officially, the SQL languages does not support a JOIN or FROM clause in an UPDATE statement unless it is in a subquery. Thus, the Hoyle ANSI approach would be something like

Update addresses
Set cid = (
            Select c.id
            From customers As c
            where c.id = a.id
            )
Where Exists    (
                Select 1
                From customers As C1
                Where C1.id = addresses.id
                )

However many DBMSs such Postgres support the use of a FROM clause in an UPDATE statement. In many cases, you are required to include the updating table and alias it in the FROM clause however I'm not sure about Postgres:

Update addresses
Set cid = c.id
From addresses As a
    Join customers As c
        On c.id = a.id

Answer 2

update addresses set cid=id where id in (select id from customers)

Answer 3

Try this one

UPDATE employee 
set EMPLOYEE.MAIDEN_NAME = 
  (SELECT ADD1 
   FROM EMPS 
   WHERE EMP_CODE=EMPLOYEE.EMP_CODE);
WHERE EMPLOYEE.EMP_CODE >='00' 
AND EMPLOYEE.EMP_CODE <='ZZ';

Answer 4

Using table aliases in the join condition:

update addresses a
set cid = b.id 
from customers b 
where a.id = b.id

Answer 5

this is Postgres UPDATE JOIN format:

UPDATE address 
SET cid = customers.id
FROM customers 
WHERE customers.id = address.id

Here's the other variations: http://mssql-to-postgresql.blogspot.com/2007/12/updates-in-postgresql-ms-sql-mysql.html