DB2数据库优化

[俎小坡]

例如A表中有aUserid，bUserid，cUserid字段，但显示的时候我肯定是不想显示id的，得join一下User表来取得UserName，我知道可以join三次User表，但有没有更简单效率的办法？难道一定要N个字段关联User表我就要join它N次


select
auserid,auserdes = (select userdes from user b where a.auserid = b.user),
buserid,buserdes = (select userdes from user b where a.bauserid = b.user),
cuserid,cuserdes = (select userdes from user b where a.causerid = b.user),
from userlist a


像这种sql在数据量大,并且字段多的时候会执行效率慢(近20000条数据查询了近1小时),怎么做优化