SQL查询主键INSIDE case case error

Question

下面的代码看起来应该可以工作，但是我得到了Only one expression can be specified in the select list when the subquery is not introduced with EXISTS。我认为这是关于testrgstr_testname上avg（testResults）的关键。

我有一张桌子上充满了一天中不同时间的测试结果。我想把日期范围内的所有污泥，灰尘和颗粒物测试结果，并将它们平均排列在一行上。

这导致了使用数据透视。唯一的问题是测试名称会根据从JAMES到FRANK的其他名称的一年中的时间而变化，这导致使用case语句来允许不同的测试名称，从而允许在关键点之后的不同列。

道歉的任何错误，因为这是剥离我的生产代码版本，我无法测试它。

 SELECT [JDTD JAMES Cutting Sludge AT] as s_at, [JDTD JAMES Cutting Sludge AO] as s_ao, 
       [JDTD JAMES Dust AT] as d_at, [JDTD JAMES Dust AO)] as d_ao, 
       [JDTD JAMES Particle_AT] as p_at, [JDTD JAMES Particle_AO] p_ao 
     ... 

返回结果集，而不是一个单一的值：

WITH 
TestData as (
     SELECT TestName, CONVERT(DECIMAL(10,2),result) as TestResult 
    FROM TestReg 
WHERE ResultDate BETWEEN @pFromDate AND @pToDate 
    and (testrgstr_testname like '%Sludge%' 
    or testrgstr_testname like '%Dust%' 
    or testrgstr_testname like '%Particle%') 
) 

SELECT CASE 
    WHEN @pCampType = 'JAMES' THEN 
     (
      SELECT [JDTD JAMES Cutting Sludge AT] as s_at, [JDTD JAMES Cutting Sludge AO] as s_ao, 
        [JDTD JAMES Dust AT] as d_at, [JDTD JAMES Dust AO)] as d_ao, 
        [JDTD JAMES Particle_AT] as p_at, [JDTD JAMES Particle_AO] p_ao 
      FROM TestData 
      PIVOT 
      ( 
       avg(TestResult) 
       FOR testrgstr_testname 
       IN ([JDTD JAMES Cutting Sludge AT],[JDTD JAMES Cutting Sludge AO], 
        [JDTD JAMES Dust AT, [JDTD JAMES Dust AO], 
        [JDTD JAMES Particle_AT],[JDTD JAMES Particle_AO]) 
      ) as pvt 
     ) 
    WHEN @pCampType = 'FRANK' THEN 
     (
      SELECT [JDTD FRANK Cutting Sludge AT] as s_at, [JDTD JAMES FRANK Sludge AO] as s_ao, 
        [JDTD FRANK Dust AT] as d_at, [JDTD FRANK Dust AO)] as d_ao, 
        [JDTD FRANK Particle_AT] as p_at, [JDTD FRANK Particle_AO] as p_ao 
      FROM TestData 
      PIVOT 
      ( 
       avg(TestResult) 
       FOR testrgstr_testname 
       IN ([JDTD JAMES Cutting Sludge AT],[JDTD JAMES Cutting Sludge AO], 
        [JDTD JAMES Dust AT, [JDTD JAMES Dust AO], 
        [JDTD JAMES Particle_AT],[JDTD JAMES Particle_AO]) 
      ) as pvt 
     ) 
    ELSE 
     (
      SELECT 'ERROR' 
     ) 
    END 

Answer 1

的问题是事实，你应该然后返回一个标量造成的。

您可以使用IF语句，并为每个案件进行陈述 - @pCampType = 'JAMES'/@pCampType = 'FRANK'或使用动态SQL：

DECLARE @SQL NVARCHAR(MAX) = ' 
    WITH 
    TestData as (
      SELECT TestName, CONVERT(DECIMAL(10,2),result) as TestResult 
     FROM TestReg 
    WHERE ResultDate BETWEEN @pFromDate AND @pToDate 
     and (testrgstr_testname like ''%Sludge%'' 
     or testrgstr_testname like ''%Dust%'' 
     or testrgstr_testname like ''%Particle%'') 
    )' 

DECLARE @InnerSelectSQL NVARCHAR(MAX) = N'' 

IF (@pCampType = 'JAMES') 
    @InnerSelectSQL = N' 
      SELECT [JDTD JAMES Cutting Sludge AT] as s_at, [JDTD JAMES Cutting Sludge AO] as s_ao, 
        [JDTD JAMES Dust AT] as d_at, [JDTD JAMES Dust AO)] as d_ao, 
        [JDTD JAMES Particle_AT] as p_at, [JDTD JAMES Particle_AO] p_ao ' 
ELSE IF (@pCampType = 'FRANK') 
    @InnerSelectSQL = N' 
      SELECT [JDTD FRANK Cutting Sludge AT] as s_at, [JDTD JAMES FRANK Sludge AO] as s_ao, 
        [JDTD FRANK Dust AT] as d_at, [JDTD FRANK Dust AO)] as d_ao, 
        [JDTD FRANK Particle_AT] as p_at, [JDTD FRANK Particle_AO] as p_ao ' 

SET @SQL = @SQL + CHAR(13) + CHAR(10) + InnerSelectSQL + CHAR(13) + CHAR(10) + N' 
    FROM TestData 
      PIVOT 
      ( 
       avg(TestResult) 
       FOR testrgstr_testname 
       IN ([JDTD JAMES Cutting Sludge AT],[JDTD JAMES Cutting Sludge AO], 
        [JDTD JAMES Dust AT, [JDTD JAMES Dust AO], 
        [JDTD JAMES Particle_AT],[JDTD JAMES Particle_AO]) 
      ) as pvt' 

Dynamic SQL is uglier, but you avoid repetition.