UPDATE `dh_mingzhan` SET name = concat('photo/', '', name)
UPDATE `dh_mingzhan` SET name = concat(name, '','photo/')
SELECT substr(name, 1, 6) as name FROM `dh_mingzhan`
UPDATE `dh_mingzhan` SET name = replace('photo/', '', name)
UPDATE `dh_mingzhan` SET name = replace(name, 'photo/', '')
select * from `dh_mingzhan` order by rand() limit 5
