SQLiteDatabase從3個表

Question

我是新來的數據庫和我有三個表

PRODUCT_INFO| FOOD_ADDITIVE_TABLE |  SUPER_TABLE 
ID CODE | ID FOOD_ADDITIVE |  ID PRODUCT_ID FOOD_ADDITIVE_ID 
1 100  | 1  E621   |  1 1   3 
2 156  | 2  E523   |  2 1   2 
3 295  | 3  E211   |  3 3   1 

比如我有代碼100所以我需要從FOOD_ADDITIVE_TABLE因爲在我SUPER_TABLE PRODUCT_ID選擇E211和E523（1）與兩種食品添加劑（3和2）相關。 所以這裏我所做的

SELECT FOOD_ADDITIVE FROM FOOD_ADDITIVE_TABLE ....And now I need JOIN 

但問題在哪裏？我沒有任何額外的信息在FOOD_ADDITIVE_TABLE加入其他表。

Answer 1

您需要JOIN在公共列三個表，然後用WHERE條款，你只能用你想要的行：

SELECT aa.FOOD_ADDITIVE 
FROM FOOD_ADDITIVE_TABLE AS aa 
INNER JOIN SUPER_TABLE AS bb 
ON aa.ID = bb.FOOD_ADDITIVE_ID 
INNER JOIN PRODUCT_INFO AS cc 
ON bb.PRODUCT_ID = cc.ID 
WHERE cc.CODE = 100; 

也可以看看here約JOIN。