Question

我有一张这样的桌子：

Date       | Name  | Pick  | Amount
-----------+-------+-------+-------
2018-01-01 | Alice | Apple |      2
2018-01-01 | Alice | Grape |      3
2018-01-01 | Bob   | Apple |      4
2018-01-02 | Alice | Apple |      5
2018-01-02 | Bob   | Grape |      6

产生如下所示结果的SQL语句是什么？

Name  | Apple | Grape | Total
------+-------+-------+------
Alice |     7 |     3 |    10
Bob   |     4 |     6 |    10

Answer 1

使用CASE条件，这是可能的。

尝试一下：

select name
    ,sum(case when pick = 'Apple' then amount end)Apple
    ,sum(case when pick = 'Grape' then amount end)Grape
    ,sum(case when pick = 'Apple' then amount end)
        +sum(case when pick = 'Grape' then amount end)Total
from your_table
group by name

Answer 2

您需要条件聚合：

select name, 
       sum(case when pick = 'Apple' then amount else 0  end) Apple,
       sum(case when pick = 'Grape' then amount else 0  end) Grape,
       sum(case when pick in ('Apple', 'Grape') then amount else 0 end) Total
from table t
group by name;

Answer 3

这也是一种使用汇总函数和or

计算结果的方法

select name, 
           sum(case when pick = 'Apple' then amount else 0  end) Apple,
           sum(case when pick = 'Grape' then amount else 0  end) Grape,
           sum(case when pick in('Apple','Grape') then amount  else 0 end) Total
    from  tableA
    group by name

http://sqlfiddle.com/#!9/4c56c/4

Answer 4

SELECT Name, 
sum(if(Pick='Apple', Amount, 0)) as Apple, 
sum(if(Pick='Grape', amount, 0)) as Grape 
FROM table_name
GROUP BY Name;

Answer 5

您可以使用嵌套查询。一种用于计算葡萄和苹果，另一种用于计算总量。优点是您可以在单个位置上计算每一列的逻辑，并且总计的计算更加直观

SELECT 
    Name,
    Apple,
    Grape,
    Apple + Grape as Total
FROM (
  SELECT
      `name` as Name,
      SUM(IF(pick = 'Apple', amount, 0)) as Apple,
      SUM(IF(pick = 'Grape', amount, 0)) as Grape
  FROM test
  GROUP BY name
) AS t1

db-fiddle

基于其他列的MySQL Sum操作

5 个答案: