子查詢in 爲什麼不能用order by

SELECT * from t_user where id in (select id from t_user order by id) [Err] ORA-00907: 缺失右括號 SELECT * from t_user where id in (select id from t_user ) 這樣就能夠？ 求原理！！！！web 出於效率，ORACLE會對IN子查詢作DISTINCT，而DIS

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