Jak mogę uzyskać wyniki wielu wyborów i połączyć w jeden wiersz?

Question

Mam tabelę, która zawiera informacje dla 4 generatorów elektrycznych Chciałbym mieć wyniki z czterech kwerend w jednym wierszu. Ktokolwiek ma jakieś sugestie. Dzięki

SELECT avg(KW) as GEN_101_AVG 
FROM   genset WHERE  (GenSetName like 'GEA3519') and GenDate >= '1 jan 2003 00:00:00' and GenDate < '1 feb 2003 00:00:00' 

    SELECT avg(KW) as GEN_201_AVG 
FROM   genset WHERE  (GenSetName like 'GEA3520') and GenDate >= '1 jan 2003 00:00:00' and GenDate < '1 feb 2003 00:00:00' 

SELECT avg(KW) as GEN_301_AVG 
FROM   genset WHERE  (GenSetName like 'GEA3521') and GenDate >= '1 jan 2003 00:00:00' and GenDate < '1 feb 2003 00:00:00' 

SELECT avg(KW) as GEN_401_AVG 
FROM   genset WHERE  (GenSetName like 'GEA3522') and GenDate >= '1 jan 2003 00:00:00' and GenDate < '1 feb 2003 00:00:00' 

MS-SQL

Answer 1

SELECT (
     SELECT avg(KW) 
     FROM genset 
     WHERE (GenSetName like 'GEA3519') 
       and GenDate >= '1 jan 2003 00:00:00' 
       and GenDate < '1 feb 2003 00:00:00' 
     ) AS avg_GEA3519, 
     (
     SELECT avg(KW) 
     FROM genset 
     WHERE (GenSetName like 'GEA3520') 
       and GenDate >= '1 jan 2003 00:00:00' 
       and GenDate < '1 feb 2003 00:00:00' 
     ) AS avg_GEA3520, 
     (
     SELECT avg(KW) 
     FROM genset 
     WHERE (GenSetName like 'GEA3521') 
       and GenDate >= '1 jan 2003 00:00:00' 
       and GenDate < '1 feb 2003 00:00:00' 
     ) AS avg_GEA3521, 
     (
     SELECT avg(KW) 
     FROM genset 
     WHERE (GenSetName like 'GEA3522') 
       and GenDate >= '1 jan 2003 00:00:00' 
       and GenDate < '1 feb 2003 00:00:00' 
     ) AS avg_GEA3522 

lub w SQL Server 2005+, to:

SELECT [GEA3519], [GEA3520], [GEA3521], [GEA3522] 
FROM (
     SELECT GenSetName, KW 
     FROM genset 
     WHERE GenDate >= '1 Jan 2003 00:00:00' 
       AND GenDate < '1 Feb 2003 00:00:00' 
     ) AS q 
PIVOT 
(
     AVG(KW) 
     FOR GenSetName IN (['GEA3519'], ['GEA3520'], ['GEA3521'], ['GEA3522'] 
) 

Answer 2

Ponieważ liczba wybiera jest ograniczona do czterech, jeden rozwiązaniem byłoby wybrać się zmienne, a następnie dokonaj ostatecznego wyboru. Jak następuje:

declare @var1 <TYPE> 
declare @var2 <TYPE> 
declare @var3 <TYPE> 
declare @var4 <TYPE> 

select @var1 = SELECT avg(...) ... 
select @var2 = ... 
select @var3 = ... 
select @var4 = ... 

select @var1 as ..., @var2 as ..., @var3 as ..., @var4 as ... 

Answer 3

Kolejna opcja:

SELECT 
    AVG(GEN_101.kw) AS GEN_101_AVG, 
    AVG(GEN_201.kw) AS GEN_201_AVG, 
    AVG(GEN_301.kw) AS GEN_301_AVG, 
    AVG(GEN_401.kw) AS GEN_401_AVG 
FROM 
    Genset GEN_101 
INNER JOIN Genset GEN_201 ON 
    GEN_201.GenSetName = 'GEA3520' AND 
    GEN_201.GenDate >= '1 jan 2003 00:00:00' AND 
    GEN_201.GenDate < '1 feb 2003 00:00:00' 
INNER JOIN Genset GEN_101 ON 
    GEN_301.GenSetName = 'GEA3521' AND 
    GEN_301.GenDate >= '1 jan 2003 00:00:00' AND 
    GEN_301.GenDate < '1 feb 2003 00:00:00' 
INNER JOIN Genset GEN_101 ON 
    GEN_401.GenSetName = 'GEA3522' AND 
    GEN_401.GenDate >= '1 jan 2003 00:00:00' AND 
    GEN_401.GenDate < '1 feb 2003 00:00:00' 
WHERE 
    GEN_101.GenSetName = 'GEA3519' AND 
    GEN_101.GenDate >= '1 jan 2003 00:00:00' AND 
    GEN_101.GenDate < '1 feb 2003 00:00:00'