歷史表狀態中的SQL查詢

Question

我對sql查詢有一個簡單的邏輯問題。

有一些文章的歷史記錄表和文章與status_id有一排。一篇文章可以具有各種各樣的地位，我只想得到這些文章，從來沒有給定的地位。例如：

articlename | status_id 
article1 | 2 
article1 | 1 
article1 | 3 
article2 | 2 
article2 | 3 
article3 | 2 
article3 | 3 


SELECT * FROM article WHERE article.status_id != 2 GROUP BY article.id 

這只是錯誤的代碼，我得到「article1」，因爲它有2行適合此聲明。我認爲解決的辦法很簡單，但我不能在此刻得到提前

Answer 1

-.-

感謝您需要使用NOT IN刪除所有有過的「2」狀態的文章。

/* NOT IN BASED APPROACH */ 
SELECT * 
FROM article 
WHERE article.id NOT IN (
    SELECT article.id 
    FROM article 
    WHERE article.status_id = 2) 

/* NOT EXISTS BASED APPROACH */ 
SELECT * 
FROM article 
WHERE article.id NOT EXISTS (
    SELECT * 
    FROM article 
    WHERE article.status_id = 2) 

/* JOIN BASED APPROACH */ 
SELECT * 
FROM article a1 LEFT JOIN 
     article a2 
     ON a1.id = a2.id 
     AND a2.status_id = 2 
WHERE a2.id IS NULL