将行数据显示为列智慧

Question

我想将行数据显示到列中。假设如果行类型增加，那么列数也会增加。信息如下：

Please see picture to get idea

Answer 1

您可以将COUNT与CASE WHEN：

一起使用

SELECT t.Name AS Type,
       COUNT(*) AS NumberOfCase,
       COUNT(CASE WHEN s.Name = 'Resolved' THEN 1 END) AS Resolved,
       COUNT(CASE WHEN s.Name = 'Pending' THEN 1 END) AS Pending,
       COUNT(CASE WHEN s.Name = 'Waiting' THEN 1 END) AS Waiting
FROM Type t
LEFT JOIN "Case" c
  ON c.CaseType = t.TypeId
LEFT JOIN "Status" s
  ON c.CaseStatus = s.StatusId
GROUP BY t.Name;

的 SqlFiddleDemo