Oracle CTE /子查询代销删除

Question

WITH RemoveDate As (
SELECT table.*, ROW_NUMBER() 
OVER (PARTITION BY id order by row_added_dttm) AS RowNumber 
FROM table 
WHERE (grp = '124') 
and row_added_dttm <= (SELECT MAX(row_added_dttm) from table 
where (grp = '124')) 
) 
delete from RemoveDate where RowNumber >1 

您好，我需要在Oracle SQL Developer上运行它，但它不起作用。我有重复，我需要删除一个和另一个必须仍然在数据库中。 Ofc不是全部都是重复的，它们也需要删除。我需要只有一个ID最新的行。

Answer 1

使用MERGE

SQL Fiddle

的Oracle 11g R2架构设置：

CREATE TABLE table_name (id, row_added_dttm) AS 
    SELECT 1, DATE '2017-09-20' FROM DUAL UNION ALL 
    SELECT 1, DATE '2017-09-19' FROM DUAL UNION ALL 
    SELECT 1, DATE '2017-09-18' FROM DUAL UNION ALL 
    SELECT 1, DATE '2017-09-17' FROM DUAL UNION ALL 
    SELECT 2, DATE '2017-09-20' FROM DUAL UNION ALL 
    SELECT 2, DATE '2017-09-18' FROM DUAL UNION ALL 
    SELECT 3, DATE '2017-09-15' FROM DUAL; 

MERGE INTO table_name t 
USING (
    SELECT ROW_NUMBER() OVER (PARTITION BY id ORDER BY row_added_dttm DESC) 
      AS RN, 
     ROWID AS rid 
    FROM table_name 
) m 
ON (t.ROWID = m.ROWID) 
WHEN MATCHED THEN 
    UPDATE SET id = id 
    DELETE WHERE m.RN > 1; 

查询1：

SELECT * 
FROM table_name 

Results：

| ID |  ROW_ADDED_DTTM | 
|----|----------------------| 
| 1 | 2017-09-20T00:00:00Z | 
| 2 | 2017-09-20T00:00:00Z | 
| 3 | 2017-09-15T00:00:00Z |