Oracle查詢重複資料並刪除，只保留一條記錄____Oracle

 

             Oracle查詢重複資料並刪除，只保留一條記錄

 

  前言

 

項目中，在“資來源目錄-線上編目”中，資源項子表存在多條重發資料，需要進行資料清理，刪除重發的資料，最終只保留一條相同的資料。

 

操作的表名：R_RESOURCE_DETAILS

  操作步驟

  一、重複記錄根據單個欄位來判斷

 

1、首先，尋找表中多餘的重複記錄，重複記錄是根據單個欄位（FIELD_CODE）來判斷

 

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

 

2、刪除表中多餘的重複記錄，重複記錄是根據單個欄位（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、重複記錄根據多個欄位來判斷

 

1、尋找表中多餘的重複記錄（多個欄位）

 

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、刪除表中多餘的重複記錄（多個欄位），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、尋找表中多餘的重複記錄（多個欄位），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)