select CODE, COUNT(ID) as CNT, GROUP_CONCAT(ID) as ID_LIST FROM yourtable WHERE IBLOCK_ID = 11 GROUP BY CODE HAVING CNT > 1 LIMIT 10#Заменить 7 на +7
UPDATE yourtable SET `PERSONAL_MOBILE` = CONCAT( '+', `PERSONAL_MOBILE`) WHERE PERSONAL_MOBILE LIKE "7%"#Заменить 8 на +7
UPDATE yourtable SET `PERSONAL_MOBILE` = CONCAT( '+7', RIGHT(PERSONAL_MOBILE, LENGTH(PERSONAL_MOBILE) - 1)) WHERE PERSONAL_MOBILE LIKE "8%"_