将多个查询转换为单行

Question

我有一个报告，我想基于单个 SQL 语句。问题是数据是基于几个 SQL 语句的。例如。

SELECT COUNT(*) as 'Cases Opened' 
FROM tblCases 
WHERE DateAssigned BETWEEN @StartDate AND @EndDate

SELECT COUNT(*) as 'Cases Closed' 
FROM tblCases 
WHERE ClosedDate BETWEEN @StartDate AND @EndDate

SELECT COUNT(*) as 'Tickets Issued' 
FROM tblTicket 
WHERE DateIssued BETWEEN @StartDate AND @EndDate

SELECT COUNT(*) as 'Warnings Issued' 
FROM tblWarning 
WHERE DateIssued BETWEEN @StartDate AND @EndDate

有没有办法将这四个单独的 SQL 语句转换为单个 SQL 语句，以便将每个结果列为一列？例如..

Cases Opened        Cases Closed       Tickets Issued        Warnings Issued
******************************************************************************
   256         |      165          |        56           |          165

编辑我使用的是 SQL Server，表之间没有关系。

Answer 1

如果您在 SQLServer 中运行，请查看 pivot 语句

Answer 2

您可以联合和旋转数据，如下所示：

SELECT SUM(CASE WHEN FieldName='Cases Opened' THEN Value ELSE 0 END) AS Cases_Opened,
       SUM(CASE WHEN FieldName='Cases Closed' THEN Value ELSE 0 END AS Cases_Closed,
       SUM(CASE WHEN FieldName='Warning Issued' THEN Value ELSE 0 END) AS Warnings_Issued,
       SUM(CASE WHEN FieldName='Tickets Issued' THEN Value ELSE 0 END) AS Tickets_Issued
FROM 
(
SELECT COUNT(*) as Value, 'Cases Opened' as FieldName
FROM tblCases 
WHERE DateAssigned BETWEEN @StartDate AND @EndDate

UNION

SELECT COUNT(*) as Value, 'Cases Closed' as FieldName
FROM tblCases 
WHERE ClosedDate BETWEEN @StartDate AND @EndDate

UNION

SELECT COUNT(*) as Value, 'Tickets Issued' as FieldName
FROM tblTicket 
WHERE DateIssued BETWEEN @StartDate AND @EndDate

UNION

SELECT COUNT(*) as Value, 'Warnings Issued' as FieldName
FROM tblWarning 
WHERE DateIssued BETWEEN @StartDate AND @EndDate
)

Answer 3

select 
 (
 SELECT COUNT(*)  
 FROM tblCases 
 WHERE DateAssigned BETWEEN @StartDate AND @EndDate
 ) as 'Cases Opened' ,
 (SELECT COUNT(*)  
 FROM tblCases 
 WHERE ClosedDate BETWEEN @StartDate AND @EndDate
 ) as 'Cases Closed' ,
 (SELECT COUNT(*)  
 FROM tblTicket 
 WHERE DateIssued BETWEEN @StartDate AND @EndDate
 ) as 'Tickets Issued' ,
 (SELECT COUNT(*) 
 FROM tblWarning 
 WHERE DateIssued BETWEEN @StartDate AND @EndDate
 )  as 'Warnings Issued'
from dual

在 oracle 中需要 from dual，mysql 支持但不是必需的，我不确定 sqlserver，因为我面前没有。