mysql 字符串去重

update tablea inner JOIN (
SELECT '新客户' AS n UNION ALL
SELECT '从未联系上' UNION ALL
SELECT '常态跟进' UNION ALL

) b set a.字段=REPLACE(REPLACE(a.字段,b.n,''),',,','')
where FIND_IN_SET(b.n,a.字段) and (LENGTH(a.字段) - LENGTH(REPLACE(a.字段,b.n,'')))>LENGTH(b.n);