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Question

我有一個表tblPersonaldata和tblStudentsadmitted

tblPersonalData 

UID Name Gender 
------------------------ 
E1 xyz M 
E2 pqr M 
E3 mno M 

tblStudentsadmitted 

UID Status Stage 
---------------------- 
E1  Y  1 
E2  Y  2 
E3  Y  1 

現在我想是這樣的數據：

Gender Stage1 Stage2 
M  2  1 

但在這種情況下，我沒有得到的數據女性性別。我想對女性性別的數據，即使它是空

我已經試過這樣：

select 
    case 
     when gender='M' then 'Male' 
     when gender='F' then 'Female' 
    end as Gender, 
    sum(case when Stage=1 then 1 else 0) end as Stage1, 
    sum(case when Stage=2 then 1 else 0) end as Stage2 
from tblPersonaldata A inner join 
     tblStudentsadmitted B on A.UID=B.UID 
where B.Status='Y' 
group by Gender 

Answer 1

SELECT CASE WHEN a.Gender = 'M' THEN 'Male' ELSE 'FEMALE' END Gender, 
     SUM(CASE WHEN Stage = 1 THEN 1 ELSE 0 END) Stage1, 
     SUM(CASE WHEN Stage = 2 THEN 1 ELSE 0 END) Stage2 
FROM personal a 
     LEFT JOIN studentadmitted b 
      ON a.UID = b.UID AND b.Status = 'Y' 
GROUP BY a.Gender 

• SQLFiddle Demo

SELECT CASE WHEN c.Gender = 'M' THEN 'Male' ELSE 'Female' END Gender, 
     SUM(CASE WHEN Stage = 1 THEN 1 ELSE 0 END) Stage1, 
     SUM(CASE WHEN Stage = 2 THEN 1 ELSE 0 END) Stage2 
FROM (SELECT 'F' Gender UNION SELECT 'M' Gender) c 
     LEFT JOIN personal a 
      ON a.Gender = c.Gender 
     LEFT JOIN studentadmitted b 
      ON a.UID = b.UID AND b.Status = 'Y' 
GROUP BY c.Gender 

• SQLFiddle Demo

輸出

╔════════╦════════╦════════╗ 
║ GENDER ║ STAGE1 ║ STAGE2 ║ 
╠════════╬════════╬════════╣ 
║ Female ║  0 ║  0 ║ 
║ Male ║  2 ║  1 ║ 
╚════════╩════════╩════════╝ 

Answer 2

在SQL Server中，你可以使用PIVOT函數生成的結果：

select gender, 
    Stage1, 
    Stage2 
from 
(
    select 
    c.gender, 
    'Stage'+cast(stage as varchar(10)) Stage 
    from (values ('F'),('M')) c (gender) 
    left join tblpersonaldata p 
    on c.gender = p.gender 
    left join tblStudentsadmitted s 
    on p.uid = s.uid 
    and s.Status='Y' 
)src 
pivot 
(
    count(stage) 
    for stage in (Stage1, Stage2) 
) piv 

見SQL Fiddle with Demo。

由於您使用的是SQL Server 2008的這個查詢使用VALUES通過其他表使用LEFT JOIN最終的結果產生你在最終結果中想要的性別的設置列表

from (values ('F'),('M')) c (gender) 

然後將爲M和F值返回一行。

這也可以使用UNION ALL產生性別的名單寫：

select gender, 
    Stage1, 
    Stage2 
from 
(
    select 
    c.gender, 
    'Stage'+cast(stage as varchar(10)) Stage 
    from 
    (
    select 'F' gender union all 
    select 'M' gender 
) c 
    left join tblpersonaldata p 
    on c.gender = p.gender 
    left join tblStudentsadmitted s 
    on p.uid = s.uid 
    and s.Status='Y' 
)src 
pivot 
(
    count(stage) 
    for stage in (Stage1, Stage2) 
) piv 

見SQL Fiddle with Demo

共同作用的結果是：

| GENDER | STAGE1 | STAGE2 | 
---------------------------- 
|  F |  0 |  0 | 
|  M |  2 |  1 | 

Answer 3

這也是工作。使用Left joins與新表（表中有兩個性別記錄M & F）。

Fiddle demo

select t.g Gender, 
     isnull(sum(case when Stage = 1 then 1 end),0) Stage1, 
     isnull(sum(case when Stage = 2 then 1 end),0) Stage2 
from (values ('M'),('F')) t(g) 
      left join personal a on t.g = a.gender 
      left join studentadmitted b on a.uid = b.uid and b.Status = 'Y' 
group by t.g 
order by t.g 

| GENDER | STAGE1 | STAGE2 | 
---------------------------- 
|  F |  0 |  0 | 
|  M |  2 |  1 | 

Answer 4

SELECT性別，0 AS 'STAGE 0'，1 AS 'STAGE 1'，2 AS 'STAGE 2'
FROM （ SELECT P.ID，性別， CASE WHEN STAGE IS NULL THEN ELSE 0 END STAGE STAGE FROM tblPersonaldata P LEFT JOIN tblStudentsadmitted S ON P.UID = S.UID ），爲 PIVOT （ COUNT（ID）FOR階段（[0]，[ 1]，[ 2]） ）P