如何在同一张表中组合多个查询

Question

我有下表：

CREATE TABLE studenttest 
(
    YEAR INT,
    DEPT VARCHAR(5),
    SEM INT,
    REGNO INT,
    NAME VARCHAR(20),
    ENGLISH VARCHAR(2),
    MATHS VARCHAR(2),
    PHYSICS VARCHAR(2),
    CHEMISTRY VARCHAR(2),
    EG VARCHAR(2),
    FOC VARCHAR(2),
    LAB1 VARCHAR(2),
    LAB2 VARCHAR(2),
    LAB3 VARCHAR(2)
)

有以下数据：

INSERT INTO studenttest 
 values
 (2010,'cse',3,1,'saravaanan','a','b','c','d','ra','f','g','h','i'),   
 (2010,'cse',3,2,'raja','ra','b','c','d','e','f','g','h','i'),
 (2010,'cse',3,3,'selvam','a','b','c','d','e','f','g','h','i')

我想查询这个数据来得到所有在任何科目中成绩不为“ra”的学生的结果集。

Answer 1

SELECT *
FROM studenttest
WHERE ENGLISH + ',' + MATHS + ',' + PHYSICS + ',' + CHEMISTRY + ',' + EG + ',' + FOC + ',' + LAB1 + ',' + LAB2 + ',' + LAB3 NOT LIKE '%ra%'

SQLFiddle上的演示

Answer 2

另一种方式：

SELECT * 
FROM studenttest
WHERE 'ra' NOT IN 
      (ENGLISH, MATHS, PHYSICS, CHEMISTRY, EG, FOC, LAB1, LAB2, LAB3) ;

Answer 3

只是@Mahmoud's version 的替代品UNPIVOT 和CTE，也可以使用UNION ALL 来完成：

SELECT Name
FROM
(
  SELECT Name, ENGLISH grade, 'English' subject
  from studenttest
  union all
  SELECT Name, MATHS grade, 'MATHS' subject
  from studenttest
  union all
  SELECT Name, PHYSICS grade, 'PHYSICS' subject
  from studenttest
  union all
  SELECT Name, CHEMISTRY grade, 'CHEMISTRY' subject
  from studenttest
  union all
  SELECT Name, EG grade, 'EG' subject
  from studenttest
  union all
  SELECT Name, FOC grade, 'FOC' subject
  from studenttest
  union all
  SELECT Name, LAB1 grade, 'LAB1' subject
  from studenttest
  union all
  SELECT Name, LAB2 grade, 'LAB2' subject
  from studenttest
  union all
  SELECT Name, LAB3 grade, 'LAB3' subject
  from studenttest
) un
where grade <> 'ra'
group by name
having count(grade) = 9

UNPIVOT 执行与UNION ALL 相同的步骤，但代码更少。当您的数据不像您的表那样规范化时，这些查询非常有用。

如果您想要所有数据（不仅仅是名称），您可以再次将上述查询重新加入到表中：

select *
from studenttest t
inner join
(
  SELECT Name
  FROM
  (
    SELECT Name, ENGLISH grade, 'English' subject
    from studenttest
    union all
    SELECT Name, MATHS grade, 'MATHS' subject
    from studenttest
    union all
    SELECT Name, PHYSICS grade, 'PHYSICS' subject
    from studenttest
    union all
    SELECT Name, CHEMISTRY grade, 'CHEMISTRY' subject
    from studenttest
    union all
    SELECT Name, EG grade, 'EG' subject
    from studenttest
    union all
    SELECT Name, FOC grade, 'FOC' subject
    from studenttest
    union all
    SELECT Name, LAB1 grade, 'LAB1' subject
    from studenttest
    union all
    SELECT Name, LAB2 grade, 'LAB2' subject
    from studenttest
    union all
    SELECT Name, LAB3 grade, 'LAB3' subject
    from studenttest
  ) un
  where grade <> 'ra'
  group by name
  having count(grade) = 9
) t2
  on t.name = t2.name

见SQL Fiddle with Demo

Answer 4

你是这个意思吗？

SELECT * 
FROM studenttest
WHERE 
    ENGLISH <> 'ra' AND
    MATHS <> 'ra' AND
    PHYSICS <> 'ra' AND
    CHEMISTRY    <> 'ra' AND
    EG  <> 'ra' AND   
    FOC <> 'ra' AND   
    LAB1 <> 'ra' AND  
    LAB2 <> 'ra' AND
    LAB3 <> 'ra'

Answer 5

你可以这样做：

WITH AllSubjectsGrades
AS
(
  SELECT Name, Grade
  FROM
  (
    SELECT 
      Name, 
      ENGLISH, MATHS, PHYSICS,  CHEMISTRY,
      EG,  FOC, LAB1, LAB2, LAB3
    FROM studenttest
  ) t
  UNPIVOT
  (
    grade
    FOR Subject IN(ENGLISH, MATHS, PHYSICS, CHEMISTRY,
                   EG,  FOC, LAB1, LAB2, LAB3)
  ) u
)
SELECT Name
FROM AllSubjectsGrades
WHERE GRADE <> 'ra'
GROUP BY Name
HAVING COUNT(GRADE) = 9;

SQL Fiddle Demo

这将只给您学生selvam，因为saravaanan 在EG 中具有“ra”，而raja 在英语中具有“ra”。但是selvam 从来没有在任何主题中得到ra。就是这样

GROUP BY Name
HAVING COUNT(GRADE) = 9;

做。

Answer 6

SELECT  a.*
FROM    studenttest a
        LEFT JOIN
        (
          SELECT regno, name
          FROM studenttest
          WHERE ENGLISH = 'ra' OR
                MATHS = 'ra' OR
                PHYSICS = 'ra' OR
                CHEMISTRY    = 'ra' OR
                EG  = 'ra' OR   
                FOC = 'ra' OR   
                LAB1 = 'ra' OR  
                LAB2 = 'ra' OR  
                LAB3 = 'ra'
        ) b ON a.regno = b.regno 
               AND a.Name = b.Name   -- this line is OPTIONAL
WHERE   b.regno IS NULL

• SQLFiddle Demo Link