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)