在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢 
1、查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断

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

2、删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录

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、查找表中多余的重复记录（多个字段）

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

4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录

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、查找表中多余的重复记录（多个字段），不包含rowid最小的记录

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.消除一个字段的左边的第一位：

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

7.消除一个字段的右边的第一位：

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

8.假删除表中多余的重复记录（多个字段），不包含rowid最小的记录

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

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