Question

我有一张包含以下内容的表：

Fruit_id     Fruit1            Fruit2
-------------------------------------
1            Apple             Orange
2            Orange            Orange
3            Orange            Orange
4            Banana            Banana
5            Apple             Orange

我想计算每个水果的总数，以便输出类似

Fruit            Frequency
---------------------------
Apple            2
Banana           2
Orange           6

我试过了

select distinct Fruit1, count(Fruit1 Fruit2) from Fruits group by Fruit1 order by count(Fruit1 Fruit2);

我也尝试过：

select distinct Fruit1, count(Fruit1 || Fruit2) from Fruits group by Fruit1 order by count(Fruit1 Fruit2);

我是oracle sql的新手所以请理解我的无知

Answer 1

您可以使用以下内容：

select fruits, count(*) as freq
  from (select fruit1 as fruits
          from tbl
        union all
        select fruit2 as fruits
          from tbl)
 group by fruits

Answer 2

您可以获取Fruit1和Fruit2列中每个不同水果值的计数，然后将这些值与SUM聚合一起添加。

“技巧”是使用内联视图将两个结果与UNION ALL集合运算符连接起来。

SELECT f.fruit, SUM(f.cnt) AS cnt
  FROM ( SELECT d.Fruit1 AS fruit, COUNT(1) AS cnt FROM Fruits d GROUP BY d.Fruit1 
          UNION ALL
         SELECT e.Fruit2 AS fruit, COUNT(1) AS cnt FROM Fruits e GROUP BY e.Fruit2
       ) f
 GROUP BY f.fruit
 ORDER BY f.fruit

从几列Oracle Sql中计算

2 个答案: