MySql怎么查詢重復(fù)的數(shù)據(jù)

select?name,sum(num)?from?table?group?by?name

成都創(chuàng)新互聯(lián)專注于企業(yè)營銷型網(wǎng)站、網(wǎng)站重做改版、坡頭網(wǎng)站定制設(shè)計、自適應(yīng)品牌網(wǎng)站建設(shè)、H5建站、商城網(wǎng)站建設(shè)、集團公司官網(wǎng)建設(shè)、成都外貿(mào)網(wǎng)站建設(shè)、高端網(wǎng)站制作、響應(yīng)式網(wǎng)頁設(shè)計等建站業(yè)務(wù)，價格優(yōu)惠性價比高，為坡頭等各大城市提供網(wǎng)站開發(fā)制作服務(wù)。

--group?by?分組查詢可以實現(xiàn)，根據(jù)名稱分組查詢累加數(shù)量

mysql 怎樣找出重復(fù)的記錄

SQL語句：SELECT `lcontent` FROM `caiji_ym_liuyan`這樣查詢的時候就會有很多重復(fù)的記錄

例子：

就會出現(xiàn)這樣的重復(fù)

2

修改后的SQL語句：

SELECT distinct(`lcontent`) FROM `caiji_ym_liuyan`

查詢結(jié)果：

mysql去重復(fù) 保留一條

mysql去重復(fù) 保留一條怎么操作呢？一起來看下吧：

1、查找表中多余的重復(fù)記錄，重復(fù)記錄是根據(jù)單個字段（peopleId）來判斷

SELECT ????* FROM ????people WHERE ????peopleId?IN?( ????????SELECT ????????????peopleId ????????FROM ????????????people ????????GROUP?BY ????????????peopleId ????????HAVING ????????????count(peopleId)??1 ????)

2、刪除表中多余的重復(fù)記錄，重復(fù)記錄是根據(jù)單個字段（peopleId）來判斷，只留有rowid最小的記錄

DELETE FROM ????people WHERE ????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、查找表中多余的重復(fù)記錄（多個字段）

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

4、刪除表中多余的重復(fù)記錄（多個字段），只留有rowid最小的記錄

DELETE FROM ????vitae?a WHERE ????(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、查找表中多余的重復(fù)記錄（多個字段），不包含rowid最小的記錄

SELECT ????* FROM ????vitae?a WHERE ????(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?tableName SET?[?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?tableName SET?[?Title?]=?LEFT?([?Title?],(len([?Title?])?-?1)) WHERE ????Title?LIKE?'%村'

8、假刪除表中多余的重復(fù)記錄（多個字段），不包含rowid最小的記錄

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