在相同的select语句中的聚合查询

Question

我有一个select语句返回给我5列（并且需要1-2分钟） 其中一列是颜色（即只有三种颜色红色，蓝色和黄色）。现在我想在同一个选择语句中显示具有红色的行数，具有蓝色的行数和具有黄色的行数。

Select语句是这个

，我想这样的

任何帮助输出？

Answer 1

你想这（对于SQL Server 2005 +）：

SELECT *, SUM(CASE WHEN Color = 'RED' THEN 1 ELSE 0 END) OVER() [RED], 
     SUM(CASE WHEN Color = 'BLUE' THEN 1 ELSE 0 END) OVER() [BLUE], 
     SUM(CASE WHEN Color = 'Yellow' THEN 1 ELSE 0 END) OVER() [Yellow] 
FROM YourTable 

Answer 2

使用CTE（公共表表达式）：

; 
WITH cte AS 
(SELECT ... 
    ... your query here 
) 
WITH grp AS 
(SELECT 
     color 
     , COUNT(*) AS cnt 
    FROM 
     cte 
    GROUP BY 
     color 
) 
SELECT 
     cte.* 
    , (SELECT cnt FROM grp WHERE color = 'Red') AS Red 
    , (SELECT cnt FROM grp WHERE color = 'Blue') AS Blue 
    , (SELECT cnt FROM grp WHERE color = 'Yellow') AS Yellow 
FROM 
     cte