查詢兩個表的重複值

Question

我有一個存儲過程，它將（或應該）記錄從一個表移動到另一個表。不過我現在要創建在「表B」

SELECT A.Num, B.Num 
FROM TableA AS A 
LEFT JOIN TableB AS B ON A.Num = B.Num 
WHERE B.Num IS NULL 

基本上，我想拉出任何數量的檢查數據「表A」對數據的過程，它是不是在「表B」，但在'TableA'，是一個LEFT JOIN的方式來做到這一點？到目前爲止，我一直未能找到丟失的文件，我已經刪除了一些文件以構成測試用例。

Answer 1

您可以使用not exists

SELECT * 
FROM TableA A 
WHERE NOT EXISTS (SELECT *  
        FROM TableB B 
        WHERE A.NUM = B.NUM); 

或not in：

SELECT * 
FROM TableA A 
WHERE A.NUM not in (SELECT B.NUM 
        FROM TableB B); 

Answer 2

SELECT Num from TableA 
EXCEPT 
SELECT Num from TableB 

Answer 3

select * from tableA 
where id not in (select id from tableB) 

或

select * from tableA a 
left join tableB b on a.id = b.id 
where b.id is null 

Answer 4

select * from tableA 
where id in (select id from tableB);