join update from 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;