MySQL在一個簡單的數據庫上加入聲明

Question

我有一個包含用於移動運營商的流行設備和品牌的數據庫。

我想爲選擇最流行的MODELS for和account +品牌創建一個連接查詢;

SELECT m1.name FROM 
    models as m1 
    JOIN accounts_to_models as am1 
     ON m1.id = am1.FK_model_id 

    JOIN brands as br 
    on br.id = m1.FK_brand_id 

    JOIN accounts as ac 
    on ac.id = am1.FK_account_id 

    WHERE ac.name = "Operator" and b1.name = "HTC" 
    ORDER BY am1.priority desc limit 10 

Answer 1

我猜對brands連接是錯誤的，因爲是在accounts的加入。試試這個：

SELECT m1.name 
FROM models m1 JOIN 
    accounts_to_models am1 
    ON m1.id = am1.FK_model_id JOIN 
    brands as b1 
    ON b1.id = m1.FK_brand_id JOIN 
--------------------^ 
    accounts as ac 
    on ac.id = am1.FK_account_id 
-----------^ 
WHERE ac.name = 'Operator' and b1.name = 'HTC' 
ORDER BY am1.priority desc 
limit 10; 

Answer 2

你在第三加盟等同ac.name與am1.FK_account_id。所以。我認爲你需要寫：

ac.id = am1.FK_account_id