查找在一個表中沒有匹配的coulmn數據存在於另一個表中的記錄

Question

我需要查詢我的數據庫，其中一個表的唯一字段出現在另一個表中，並使用此我需要僅提取第二個表中的記錄表1中的記錄在錶行中沒有匹配的字段。

Answer 1

SELECT * FROM SECOND TABLE WHERE COLUMN_ID NOT IN(SELECT COLUMN_ID FROM FIRST TABLE); 

瞭解更多關於NOT IN來自：

http://www.w3schools.com/sql/sql_in.asp

Answer 2

試試這個：
在一個表中不存在查找記錄在另一臺之間或NOT IN 差異，LEFT JOIN和NOT存在。

SELECT a.i 
FROM tableA AS a 
WHERE a.i NOT IN (SELECT b.j FROM tableB AS b) OR a.i IS NULL 
----------OR There are at least three other ways to do this, which all are much more efficient! 
    SELECT a.i FROM tableA AS a 
     WHERE a.i NOT IN (SELECT b.j FROM tableB AS b) 
     UNION ALL 
     SELECT a.i 
     FROM tableA AS a 
     WHERE a.i IS NULL 
    ----------OR 
     SELECT a.i 
     FROM tableA AS a 
     LEFT JOIN tableB AS b ON b.j = a.i 
     WHERE b.j IS NULL 
    ----------OR  
     SELECT a.i 
     FROM tableA AS a 
     WHERE NOT EXISTS (SELECT * FROM tableB AS b WHERE b.j = a.i)