Question

我有一个SQL查询，我希望能够计算优先级总数，该优先级的值设置为低，中，高或未指定。

当前最多计数13行，我希望会有多列，例如... 2，4，0

代码：

 SELECT c.Name, COUNT(*) as Count_By_Priority, 
 CASE WHEN cb.Priority = 0 THEN "Unspecified" WHEN cb.Priority = 1 THEN "Low" WHEN cb.Priority = 2 THEN "Medium" WHEN cb.Priority = 3 THEN "High" END as PriorityNumber 
 FROM TABLE 1 cb 
 LEFT JOIN Co c ON c.Id = cb.Id 
 WHERE c.Name LIKE %Name%" 
 GROUP BY c.Id;

当我期望较低或其他选择时，似乎会为优先级键打印“未指定”。

Answer 1

我很确定您可以将group by子句更改为c.Id，然后再PriorityNumber：

SELECT 
    c.Name,
    COUNT(*) as Count_By_Priority,
    CASE 
        WHEN cb.Priority = 0 THEN "Unspecified"
        WHEN cb.Priority = 1 THEN "Low"
        WHEN cb.Priority = 2 THEN "Medium"
        WHEN cb.Priority = 3 THEN "High" 
    END as PriorityNumber
FROM TABLE 1 cb 
LEFT JOIN Co c 
ON c.Id = cb.Id
WHERE c.Name LIKE %Name%"
GROUP BY c.Id, PriorityNumber;

Answer 2

尝试一下

SELECT c.Name, COUNT(*) as Count_By_Priority,
CASE WHEN cb.Priority = 0 THEN "Unspecified" 
WHEN cb.Priority = 1 THEN "Low" 
WHEN cb.Priority = 2 THEN "Medium" 
WHEN cb.Priority = 3 THEN "High" END as PriorityNumber 

FROM TABLE 1 cb LEFT JOIN Co c ON c.Id = cb.Id 

WHERE c.Name LIKE %Name%" 

GROUP BY c.Name,PriorityNumber ;

Answer 3

您正在使用聚合，但是您的SELECT与GROUP BY不一致。我认为您打算这样做：

SELECT c.Name, COUNT(*) as Count_By_Priority, 
       (CASE WHEN MAX(cb.Priority) = 0 THEN 'Unspecified'
             WHEN MAX(cb.Priority) = 1 THEN 'Low'
             WHEN MAX(cb.Priority) = 2 THEN 'Medium'
             WHEN MAX(cb.Priority) = 3 THEN 'High'
        END) as PriorityNumber 
FROM TABLE 1 cb LEFT JOIN
     Co c
     ON c.Id = cb.Id 
WHERE c.Name LIKE '%Name%'
GROUP BY c.Id;

我不确定您是否想要MAX()或MIN()，但MAX()对我来说有意义。

Answer 4

如果要在单独的列中计算每个优先级，请使用条件聚合。

SELECT c.Name, 
 sum(CASE WHEN cb.Priority = 0 THEN 1 else 0 end) as "Unspecified" 
 sum(case WHEN cb.Priority = 1 THEN 1 else 0 end) as "Low" 
 sum(case WHEN cb.Priority = 2 THEN 1 else 0 end) as "Medium" 
 sum(case WHEN cb.Priority = 3 THEN 1 else 0 end) as "High"  
 FROM TABLE 1 cb 
 LEFT JOIN Co c ON c.Id = cb.Id 
 WHERE c.Name LIKE %Name%" 
 GROUP BY c.name;

SQL为每个值计算数字

4 个答案: