保留一條，mysql去重複

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mysql去重複 保留一條怎麼操作呢？一起來看下吧：

1、查找表中多餘的重複記錄，重複記錄是根據單個字段（peopleId）來判斷

SELECT    *FROM    peopleWHERE    peopleId IN (        SELECT            peopleId        FROM            people        GROUP BY            peopleId        HAVING            count(peopleId) > 1    )

2、刪除表中多餘的重複記錄，重複記錄是根據單個字段（peopleId）來判斷，只留有rowid最小的記錄

DELETEFROM    peopleWHERE    peopleName IN (        SELECT            peopleName        FROM            people        GROUP BY            peopleName        HAVING            count(peopleName) > 1    )AND peopleId NOT IN (    SELECT        min(peopleId)    FROM        people    GROUP BY        peopleName    HAVING        count(peopleName) > 1)

3、查找表中多餘的重複記錄（多個字段）

SELECT    *FROM    vitae aWHERE    (a.peopleId, a.seq) IN (        SELECT            peopleId,            seq        FROM            vitae        GROUP BY            peopleId,            seq        HAVING            count(*) > 1    )

4、刪除表中多餘的重複記錄（多個字段），只留有rowid最小的記錄

DELETEFROM    vitae aWHERE    (a.peopleId, a.seq) IN (        SELECT            peopleId,            seq        FROM            vitae        GROUP BY            peopleId,            seq        HAVING            count(*) > 1    )AND rowid NOT IN (    SELECT        min(rowid)    FROM        vitae    GROUP BY        peopleId,        seq    HAVING        count(*) > 1)

5、查找表中多餘的重複記錄（多個字段），不包含rowid最小的記錄

SELECT    *FROM    vitae aWHERE    (a.peopleId, a.seq) IN (        SELECT            peopleId,            seq        FROM            vitae        GROUP BY            peopleId,            seq        HAVING            count(*) > 1    )AND rowid NOT IN (    SELECT        min(rowid)    FROM        vitae    GROUP BY        peopleId,        seq    HAVING        count(*) > 1)

6、消除一個字段的左邊的第一位：

UPDATE tableNameSET [ Title ]= RIGHT ([ Title ],(len([ Title ]) - 1))WHERE    Title LIKE '村%'

7、消除一個字段的右邊的第一位：

UPDATE tableNameSET [ Title ]= LEFT ([ Title ],(len([ Title ]) - 1))WHERE    Title LIKE '%村'

8、假刪除表中多餘的重複記錄（多個字段），不包含rowid最小的記錄

UPDATE vitaeSET ispass =- 1WHERE    peopleId IN (        SELECT            peopleId        FROM            vitae        GROUP BY            peopleId