Tsql 分组依据，但包含“缺少”值

假设我有以下内容

select
  case
    when fcompany = 'Acme' then 'Red'
    when fcompany = 'Acme Rockets' then 'Blue'
    else 'Green'
  end
    Color
,sum(fann_sales)
FROM
  slcdpm
group by
  case
    when fcompany = 'Acme' then 'Red'
    when fcompany = 'Acme Rockets' then 'Blue'
    else 'Green'
  end

假设它通常只返回两种颜色。拉取所有三种颜色并为缺少的值包含0的最佳方法是什么

---

全联盟

是的，联合所有人可能是你最好的选择

SELECT 'red' AS Color, sum(fann_sales) FROM slcdpm WHERE fcompany = 'Acme' GROUP BY fcompany
UNION ALL
SELECT 'blue' AS Color, sum(fann_sales) FROM slcdpm WHERE fcompany = 'Acme Rockets' GROUP BY fcompany
UNION ALL
SELECT 'green' AS Color, sum(fann_sales) FROM slcdpm WHERE fcompany <> 'Acme' AND fcompany <> 'Acme Rockets' GROUP BY fcompany

试试这个：

SELECT  b.Color, 
                sum(fann_sales) 
 FROM   (
                SELECT  case
                                    when fcompany = 'Acme' then 'Red'
                                    when fcompany = 'Acme Rockets' then 'Blue'
                                    else 'Green'
                                end
                                Color,
                                fann_sales
                    FROM slcdpm
            ) a  RIGHT JOIN 
            (
                SELECT 'Red' AS Color
                UNION ALL
                SELECT 'Blue' AS Color
                UNION ALL
                SELECT 'Green' AS Color
            ) b
        ON a.Color = b.Color            
 GROUP BY  b.Color

---

如果必须显示所有颜色，为什么不将它们显示为列

SELECT
    (SELECT sum(fann_sales) FROM slcdpm WHERE fcompany = 'Acme') AS RedSum,
    (SELECT sum(fann_sales) FROM slcdpm WHERE fcompany = 'Acme Rockets') AS BlueSum,
    (SELECT sum(fann_sales) FROM slcdpm WHERE fcompany <> 'Acme' AND fcompany <> 'Acme Rockets') AS GreenSum

---

否则，只需使用@JohnK813 answer。

将组移动到包含更多列的条件和中

select
  sum(CASE WHEN fcompany = 'Acme'
                     THEN fann_sales ELSE 0 END) AS redsales,
  sum(CASE WHEN fcompany = 'Acme Rockets'
                     THEN fann_sales ELSE 0 END) AS bluesales
  sum(CASE WHEN fcompany NOT IN ('Acme Rockets', 'Acme')
                     THEN fann_sales ELSE 0 END) AS greensales
FROM
  slcdpm

---

这件事只需一次。其他答案中的UNION ALL或subquery方法将按子句触及表一次=稍微慢一点

@Andriy M:你是说简单对搜索的案子？如果没有，请正确计算每种颜色的总和？如果是，IN不能被清晰地表示，这是一致的是，简单vs搜索。你对IN的看法是对的，但是不必担心，因为你会用其他的东西来代替它。