SELECT `nazvanie` AS 'Регион'
FROM `region`
WHERE `kod_region` = ( SELECT `kod_region` FROM `gorod` WHERE `kod_gorod`
= ( SELECT `kod_gorod` FROM `ulica` WHERE `kod_ulica`
= ( SELECT `kod_ulica` FROM `dannie` WHERE `fam` = 'Петров')))
SELECT `nazvanie` , `gorod`, `ulica`
FROM `dannie` as D LEFT JOIN `ulica` as U on D.`kod_ulica` = U.`kod_ulica`
LEFT JOIN `gorod` as G on U.`kod_gorod` = G.`kod_gorod`
LEFT JOIN `region` as R on G.`kod_region` = R.`kod_region`