數(shù)據(jù)庫(kù)查詢?nèi)コ貜?fù)數(shù)據(jù) Mysql如何去掉數(shù)據(jù)庫(kù)中的重復(fù)記錄?
Mysql如何去掉數(shù)據(jù)庫(kù)中的重復(fù)記錄?很簡(jiǎn)單 通過(guò)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(kù)中的重復(fù)記錄?
很簡(jiǎn)單 通過(guò)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數(shù)據(jù)庫(kù)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(gè)結(jié)果寫到一個(gè)臨時(shí)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!