Oracle查詢重復數據並刪除，只保留一條記錄

前言
 

項目中，在“資源目錄-在線編目”中，資源項子表存在多條重發數據，需要進行數據清理，刪除重發的數據，最終只保留一條相同的數據。

 

操作的表名：R_RESOURCE_DETAILS

 

操作步驟
 

一、重復記錄根據單個字段來判斷
 

1、首先，查找表中多余的重復記錄，重復記錄是根據單個字段（FIELD_CODE）來判斷

 

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、刪除表中多余的重復記錄，重復記錄是根據單個字段（FIELD_CODE）來判斷，只留有rowid最小的記錄

 

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、重復記錄根據多個字段來判斷
 

1、查找表中多余的重復記錄（多個字段）

 

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、刪除表中多余的重復記錄（多個字段），只留有rowid最小的記錄

 

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、查找表中多余的重復記錄（多個字段），不包含rowid最小的記錄

 

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)