我有一个像这样的表my_table
+------------+--------+--------+
| product | type_1 | type_2 |
+------------+--------+--------+
| Banana | A1 | B1 |
| Banana | B1 | B2 |
| Watermelon | A | B3 |
| Orange | B | B4 |
+------------+--------+--------+
所以我想查询是否为香蕉产品,然后返回type_2,而另一个产品返回type_1
所以预期结果就是这样
+------------+------+
| product | type |
+------------+------+
| Banana | B1 |
| Banana | B2 |
| Watermelon | A |
| Orange | B |
+------------+------+
您可以使用CASE选择所需的列。
SELECT product, CASE produt
WHEN 'Banana' THEN type_2
ELSE type_1
END as type
FROM my_table