sql - 如何在同一个表中组合多个查询

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)
)

使用以下数据:

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')

我想查询此数据以获取在任何科目中都没有“ra”成绩的所有学生的结果集。

Answer 1

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

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