mysql query update into other table code example

Example 1: update left join mysql

UPDATE  t1
LEFT JOIN
        t2
ON      t2.id = t1.id
SET     t1.col1 = newvalue
WHERE   t2.id IS NULL

Example 2: mysql update table from select on another table

UPDATE TableB 
SET TableB.value = (
    SELECT TableA.value 
    FROM TableA
    WHERE TableA.name = TableB.name
);