sql查詢數據庫表中重復數值 查詢表中id重復的值select id from 表名 group by id having count gt 查詢表中的重復記錄,重復記錄是根據id重復做判定select from 表名 where id in select id from 表名 group by id having count gt 刪除表中多余的重復記錄,重復記錄根據id重復做判定,只留rowi ...
2021-11-18 14:27 0 1054 推薦指數:
{ overflow-x: initial !important } :root { --bg-color: #ffffff; --text-color: #333333; --select-tex ...
1、查詢表中重復數據。select * from people where peopleId in (select peopleId from people group ...
表名:hztj 字段名:edxzqhdm ,sdxzqhdm 1.查出某一列數據中重復的,以sdxzqhdm為例 select * from hztj a where (a.sdxzqhdm) in (select sdxzqhdm from hztj group by sdxzqhdm ...
select train_code,count(1) from tb_ask_trainbodyroadtrain group by train_code having count(1) >1 ...
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select * from tablename where id in (select id from tablename group by id having count(id) > 1) ...
有的時候需要對數據庫的某個字段要求不能重復,所以要設置這個字段的唯一性 1. 把這個字段設置成主鍵 把phonumber設置為主鍵 2. 要是不想設置為主鍵,那可以為它增加UNIQUE屬性,在創建表的時候設置,要是設置某個字段的唯一性,那么這個字段也要設置NOT NULL ...