mysql重復(fù)數(shù)據(jù)去重 Mysql如何去掉數(shù)據(jù)庫中的重復(fù)記錄?
Mysql如何去掉數(shù)據(jù)庫中的重復(fù)記錄?很簡單 通過id刪除DELETE FROMtable_name AS ta WHEREta.唯一鍵 <> (SELECTt.maxid FROM( SEL
Mysql如何去掉數(shù)據(jù)庫中的重復(fù)記錄?
很簡單 通過id刪除
DELETE
FROM
table_name AS ta
WHERE
ta.唯一鍵 <> (
SELECT
t.maxid
FROM
( SELECT max( tb.唯一鍵 ) AS maxid FROM table_name AS tb WHERE ta.判斷重復(fù)的列 = tb.判斷重復(fù)的列 ) t
)
mysql查找刪除重復(fù)數(shù)據(jù)并只保留一條實例詳解?
delete from `mygame_article` where title in (select title from `mygame_article` group by id having count(title) > 1) and id not in (select max(id) from `mygame_article` group by title having count(title) > 1) 隨手寫了個,前半句是選擇title重復(fù)的數(shù)據(jù),后半句是剔除id最大的,delete是刪除的意思。。應(yīng)該 思路是沒問題的,這邊不方便幫您測試
Mysql數(shù)據(jù)庫中多條重復(fù)數(shù)據(jù),如何只刪除一條?
列出要保留的記錄ID,可以把這個結(jié)果寫到一個臨時表t1中: SELECT MAX(id) AS max_id FROM pedigree GROUP BY number然后:DELETE FROM pedigree WHERE id NOT IN (SELECT id FROM t1)也就是:delete from pedigree where id not in(select * from pedigree where group by number)。pedigree where id not in(select max(id) from pedigree where group by number having count(id) > 0) 查詢結(jié)果是否符合刪除要求!