在“IN CLAUSE”mysql php中返回null或空字符串

Question

我有這個問題：

SELECT * from tbl WHERE id = 1 AND option IN (1,2,3) 

表：

+-------+---------+-------+
| id    | option  | votes |
+-------+---------+-------+
|   1   |    1    |  100  |
|   1   |    2    |  150  |
+-------+---------+-------+

由於選項no.3在表中尚不存在，我希望它返回null /空字符串，所以我可以在我的php代碼中將'votes'設置為0。

目前它只給出了我所期望的選項1和2的行。

Answer 1

SELECT * from tbl t1
RIGHT JOIN 
(SELECT 1 AS opt UNION ALL
 SELECT 2 AS opt UNION ALL
 SELECT 3 AS opt UNION ALL
) t2
ON t1.option = t2.opt
WHERE t1.id = 1