mysql select * where id in (select 字符串 from . )有关问题

mysql select *... where id in (select 字符串 from ... )问题？
mysql select *... where id in (select 字符串 from ... )问题？其中字符串的内容是'12,11,10,4'；如何才能让内容成为12,11,10,4

[解决办法]
没有理解你的的意思
select *... where id IN(12,11,10,4)?