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1、幾個(gè)刪除重復(fù)記錄的SQL語句幾個(gè)刪除重復(fù)記錄的SQL語句1.用rowid方法2.用groupby方法3.用distinct方法1。用rowid方法據(jù)據(jù)oracle帶的rowid屬性,進(jìn)行判斷,是否存在重復(fù),語句如下:查數(shù)據(jù):select*fromtable1awhererowid!=(selectmax(rowid)fromtable1bwherea.name1=b.name1anda.name2=b.name2......)刪數(shù)據(jù):deletefromtable1awhererowid!=(selectmax(rowid)fromtable1bw
2、herea.name1=b.name1anda.name2=b.name2......)2.groupby方法查數(shù)據(jù): selectcount(num),max(name)fromstudent--列出重復(fù)的記錄數(shù),并列出他的name屬性 groupbynum havingcount(num)>1--按num分組后找出表中num列重復(fù),即出現(xiàn)次數(shù)大于一次刪數(shù)據(jù): deletefromstudent groupbynum havingcount(num)>1 這樣的話就把所有重復(fù)的都刪除了。3.用distinct方法-對于小的表比較有用
3、createtabletable_newasselectdistinct*fromtable1minuxtruncatetabletable1;insertintotable1select*fromtable_new;查詢及刪除重復(fù)記錄的方法大全1、查找表中多余的重復(fù)記錄,重復(fù)記錄是根據(jù)單個(gè)字段(peopleId)來判斷select*frompeoplewherepeopleIdin(selectpeopleIdfrompeoplegroupbypeopleIdhavingcount(peopleId)>1)2、刪除表中多余的重復(fù)記錄,重復(fù)記錄是根
4、據(jù)單個(gè)字段(peopleId)來判斷,只留有rowid最小的記錄deletefrompeoplewherepeopleIdin(selectpeopleIdfrompeoplegroupbypeopleIdhavingcount(peopleId)>1)androwidnotin(selectmin(rowid)frompeoplegroupbypeopleIdhavingcount(peopleId)>1)3、查找表中多余的重復(fù)記錄(多個(gè)字段)select*fromvitaeawhere(a.peopleId,a.seq)in(selectpeo
5、pleId,seqfromvitaegroupbypeopleId,seqhavingcount(*)>1)4、刪除表中多余的重復(fù)記錄(多個(gè)字段),只留有rowid最小的記錄deletefromvitaeawhere(a.peopleId,a.seq)in(selectpeopleId,seqfromvitaegroupbypeopleId,seqhavingcount(*)>1)androwidnotin(selectmin(rowid)fromvitaegroupbypeopleId,seqhavingcount(*)>1)5、查找表中多余的重
6、復(fù)記錄(多個(gè)字段),不包含rowid最小的記錄select*fromvitaeawhere(a.peopleId,a.seq)in(selectpeopleId,seqfromvitaegroupbypeopleId,seqhavingcount(*)>1)androwidnotin(selectmin(rowid)fromvitaegroupbypeopleId,seqhavingcount(*)>1)(二)比方說在A表中存在一個(gè)字段“name”,而且不同記錄之間的“name”值有可能會(huì)相同,現(xiàn)在就是需要查詢出在該表中的各記錄之間,“name”值
7、存在重復(fù)的項(xiàng);SelectName,Count(*)FromAGroupByNameHavingCount(*)>1如果還查性別也相同大則如下:SelectName,sex,Count(*)FromAGroupByName,sexHavingCount(*)>1(三)方法一declare@maxinteger,@idintegerdeclarecur_rowscursorlocalforselect主字段,count(*)from表名groupby主字段havingcount(*)>;1opencur_rowsfetchcur_rowsinto@i
8、d,@maxwhile@@fetch_status=0beginselect@max=@max-1setrowcount@