SQL Server CE：如何将两个查询的结果合并为一行？

Question

我有两个查询，它们从不同的表返回一个值（并且不以任何方式通过关系连接），并且我试图将两个查询的输出合并到单个行中，但是却遇到语法错误。 这是我正在尝试的：

SELECT
    (SELECT Timestamp As StartDate 
     FROM Events 
     WHERE Description = 'Inserted') AS StartDate,
    (SELECT TOP (1) Timestamp As EndDate 
     FROM DataStore 
     ORDER BY Timestamp DESC) AS EndDate

这就是我要返回的内容：

解析查询时出错。 [令牌行号= 2，令牌行偏移量= 2，令牌错误= SELECT]

查询1自行返回：“ 2015-06-10 11：43：34.000”，查询2返回：“ 2015-06-11 13：59：47.000”

我想返回包含两列的一行，查询1的输出作为“ StartDate”列，查询2的输出作为“ EndDate”列。

Answer 1

与第二个查询不同，第一个查询可能返回2个或多个值。 尝试在第一个查询中也放入TOP (1) ，因为我认为您只是在争取最好的结果。

SELECT
(SELECT TOP (1) Timestamp As StartDate FROM Events WHERE Description = 'Inserted') AS StartDate,
(SELECT TOP (1) Timestamp As EndDate FROM DataStore Order by Timestamp DESC) AS EndDate

请参阅此SQL Fiddle链接以获得我所做的测试。

Answer 2

declare @q1 as varchar(max)
declare @q2 as varchar(max)
SELECT @q1= Timestamp FROM Events WHERE Description = 'Inserted' 
SELECT TOP (1) @q2= Timestamp FROM DataStore Order by Timestamp DESC
select @q1 as StartDate, @q2 as EndDate

Answer 3

SQL CE不支持这种嵌套SELECT语句，因此您必须使用两个SELECT语句并使用UNION或两次调用ExecuteNonQuery。

Answer 4

尝试这个：

SELECT StartDate.StartDate, EndDate.EndDate
FROM
(SELECT Timestamp As StartDate FROM Events WHERE Description = 'Inserted') AS StartDate
CROSS JOIN
(SELECT TOP (1) Timestamp As EndDate FROM DataStore Order by Timestamp DESC) AS EndDate