sql server转mysql，有一个语句不会求sql大神?报错

SELECT rp.moduleid,convert(varchar,( SELECT ','+p2.popedomCode FROM Manage_user mu2 LEFT JOIN DRolePopedom rp2 ON mu2.usertype = rp2.RoleId LEFT JOIN DPopedom p2 ON rp2.PopedomId = p2.popedomId
WHERE
rp.moduleid=rp2.moduleid and rp.RoleId=rp2.RoleId and mu2.userid=mu.userid for xml path('')
 )) popedomCode
 FROM
Manage_user mu
LEFT JOIN DRolePopedom rp ON mu.usertype = rp.RoleId
LEFT JOIN DPopedom p ON rp.PopedomId = p.popedomId
WHERE
mu.userid = ?

 GROUP BY  rp.moduleid,rp.RoleId,mu.userid

这事sqlserver的语句 现在知道conver  mysql没有varchar  我该为char   放在后面 但还是报错。求mysql应该怎么写