求写一个MYSQL替换语句，使得2个字段的值相等

update pre_forum_typeoptionvar set value = (select subject form pre_forum_thread where pre_forum_thread.tid = (select tid from pre_forum_typeoptionvar where optionid=33))

select * from 表名 where match_id in (select match_id from 表名 where team_id='a' or team_id='b' group by match_id)

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