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  • 删除重复数据

    一、重复记录根据单个字段来判断

    1、首先,查找表中多余的重复记录,重复记录是根据单个字段(FIELD_CODE)来判断

    select * from R_RESOURCE_DETAILS where FIELD_CODE in(select FIELD_CODE from R_RESOURCE_DETAILS group by FIELD_CODE having count(FIELD_CODE) >1)

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

    delete from R_RESOURCE_DETAILS where (FIELD_CODE) in (select FIELD_CODE from R_RESOURCE_DETAILS group by FIELD_CODE having count(FIELD_CODE) >1) and rowid not in (select min(rowid) from R_RESOURCE_DETAILS group by FIELD_CODE having count(*)>1)

    二、重复记录根据多个字段来判断

    1、查找表中多余的重复记录(多个字段)

    select * from R_RESOURCE_DETAILS a where (a.FIELD_CODE,a.DTA_ITEM_NAME) in(select FIELD_CODE,DTA_ITEM_NAME from R_RESOURCE_DETAILS group by FIELD_CODE,DTA_ITEM_NAME having count(*) > 1)

    2、删除表中多余的重复记录(多个字段),只留有rowid最小的记录

    delete from R_RESOURCE_DETAILS a where (a.FIELD_CODE,a.DTA_ITEM_NAME) in (select FIELD_CODE,DTA_ITEM_NAME from R_RESOURCE_DETAILS group by FIELD_CODE,DTA_ITEM_NAME having count(*) > 1) and rowid not in (select min(rowid) from R_RESOURCE_DETAILS group by FIELD_CODE,DTA_ITEM_NAME having count(*)>1)

    3、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 R_RESOURCE_DETAILS a where (a.FIELD_CODE,a.DTA_ITEM_NAME) in (select FIELD_CODE,DTA_ITEM_NAME from R_RESOURCE_DETAILS group by FIELD_CODE,DTA_ITEM_NAME having count(*) > 1) and rowid not in (select min(rowid) from R_RESOURCE_DETAILS group by FIELD_CODE,DTA_ITEM_NAME having count(*)>1)

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  • 原文地址:https://www.cnblogs.com/zhanglin123/p/14367175.html
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