请求大家帮忙优化一个语句！
[table=95%][tr][td][font=FixedSys]
update cdb_members set extcredits4=extcredits4 100 where uid in (select authorid from cdb_posts where tid=205021) ;[/font][/td][/tr][/table]
现在这样效率太低了，希望大家协助！
[table=95%][tr][td][font=FixedSys]update cdb_members as a,cdb_posts as b set a.extcredits4=a.extcredits4 100 where a.uid = b.authorid and b.tid = 205021[/font][/td][/tr][/table]
感谢楼上，又学会了一招。
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