我有这个查询:
SELECT * from tbl WHERE id = 1 AND option IN (1,2,3)
桌子:
+-------+---------+-------+
| id | option | votes |
+-------+---------+-------+
| 1 | 1 | 100 |
| 1 | 2 | 150 |
+-------+---------+-------+
由于表中尚不存在选项 3,我希望它返回 null/空字符串,这样我就可以在我的 php 代码中将"votes"设置为 0。
目前,它只按预期为我提供了选项 1 和 2 行。
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