如何從兩列中獲得不同值的計數？

Question

我有一個如下表，我想從兩列（fruit1和fruit2）中計算出不同的值

+------+--------+--------+--------+------+
| s_id | s_name | fruit1 | fruit2 | rs   |
+------+--------+--------+--------+------+
|    1 | ram    | apple  | mango  |   20 |
|    2 | raj    | apple  | banana |   13 |
|    3 | aman   | orange | banana |    7 |
|    4 | mangal | orange | apple  |   16 |
|    5 | ravi   | apple  | banana |   17 |
|    6 | pawan  | apple  | apple  |    9 |
|    7 | shyam  | apple  | orange |   11 |
+------+--------+--------+--------+------+

我可以使用下面的命令在一列中執行此操作，但對於兩列則無法成功執行，但無法獲得實現方法。

選擇fruit1，count（*）作為s1的s_info組中的fruit1計數；

導致

+--------+-------+
| fruit1 | count |
+--------+-------+
| apple  |     5 |
| orange |     2 |
+--------+-------+

但是下面是我沒有得到的預期結果。

+--------+-------+
| fruits | count |
+--------+-------+
| apple  |     7 |
| orange |     3 |
| banana |     3 |
| mango  |     1 |
+--------+-------+

Answer 1

在進行最終聚合之前，請使用union all ：

select fruit, count(*)
from ((select fruit1 as fruit from s_info) union all
      (select fruit2 as fruit from s_info)
     ) i
group by fruit;