update using join code example

Example 1: how to add where command in update comand with joins

UPDATE A
SET foo = B.bar
FROM TableA A
JOIN TableB B
    ON A.col1 = B.colx
WHERE ...

Example 2: inner join update

UPDATE 
    t1
SET 
    t1.c1 = t2.c2,
    t1.c2 = expression,
    ...   
FROM 
    t1
    [INNER | LEFT] JOIN t2 ON join_predicate
WHERE 
    where_predicate;

Example 3: update with join

UPDATE
        first_table ft
        JOIN second_table st ON st.some_id = ft.some_id
        JOIN third_table tt  ON tt.some_id = st.some_id
        .....
    SET
        ft.some_column = some_value
    WHERE ft.some_column = 123456 AND st.some_column = 123456

Example 4: update from select join

UPDATE t1
SET t1.COL1 = t2.COL1, t1.COL2 = t2.COL2
FROM my_table AS t1
JOIN my_other_table AS t2 ON t1.COLID = t2.ID
WHERE t1.COL3 = 'OK';