mysql update field from another table code example

Example 1: update table from another table mysql

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

Example 2: mysql update table from another table

UPDATE tableB
INNER JOIN tableA ON tableB.name = tableA.name
SET tableB.value = IF(tableA.value > 0, tableA.value, tableB.value)
WHERE tableA.name = 'Joe'