UPDATE t1
LEFT JOIN
t2
ON t2.id = t1.id
SET t1.col1 = newvalue
WHERE t2.id IS NULL
UPDATE business AS b
INNER JOIN business_geocode AS g ON b.business_id = g.business_id
SET b.mapx = g.latitude,
b.mapy = g.longitude
WHERE (b.mapx = '' or b.mapx = 0) and
g.latitude > 0
UPDATE employees
LEFT JOIN
merits ON employees.performance = merits.performance
SET
salary = salary + salary * 0.015
WHERE
merits.percentage IS NULL;Code language: SQL (Structured Query Language) (sql)