删除oracle中两列组合的重复项

Question

我有一个 table 例如：端口 Table

S No	A Port	B port
1	80	100
2	90	110
3	100	80
4	94	106

我要删除记录号。 3 因为它与记录号具有相同的组合。 1 如何在 Oracle 中执行此操作？

Answer 1

在 mysql 试过这个，做一些 test/scenarios

SELECT P1.* FROM port_tbl AS P1 
LEFT JOIN port_tbl AS P2 ON P1.port1 = P2.port2 OR P1.port2 = P2.port1 
WHERE P1.id < P2.id OR ISNULL(P2.id) 
ORDER BY P1.id;

Answer 2

您可以使用单个 MERGE 语句和 ROW_NUMBER 分析函数结合 GREATEST 和 LEAST 来查找和删除重复项：

MERGE INTO table_name dst
USING (
  SELECT ROWID rid,
         ROW_NUMBER() OVER (
           PARTITION BY LEAST(A_Port, B_Port), GREATEST(A_Port, B_Port)
           ORDER BY S_no
         ) AS rn
  FROM   table_name
) src
ON (dst.ROWID = src.rid AND src.rn > 1)
WHEN MATCHED THEN
  UPDATE SET A_port = NULL
  DELETE WHERE 1 = 1;

其中，对于您的样本数据：

CREATE TABLE table_name (S_No, A_Port, B_port) AS
SELECT 1,  80, 100 FROM DUAL UNION ALL
SELECT 2,  90, 110 FROM DUAL UNION ALL
SELECT 3, 100,  80 FROM DUAL UNION ALL
SELECT 4,  94, 106 FROM DUAL;

将删除第 3 行。

db<>fiddle here

删除oracle中两列组合的重复项

Deleting duplicates on combination of two columns in oracle

sql

oracle