は、私はあなたが私に助けてくださいますMySQLでこのクエリを書きたい

Question

私のクエリです：（部屋115に会う5人の以上の学生が在籍していどちらかのすべてのクラスの名前を検索します。）

CREATE TABLE STUDENT (
    sid NUMERIC(6) NOT NULL, 
    sname VARCHAR(15), 
    major VARCHAR(20), 
    level VARCHAR(2), 
    sage NUMERIC(2) NOT NULL, 
    PRIMARY KEY (sid) 
    ); 
CREATE TABLE CLASS(
    cnum VARCHAR(6), 
    meets_at TIME, 
    room VARCHAR(6), 
    fid NUMERIC(6) , 
    PRIMARY KEY (cnum), 
    FOREIGN KEY (fid) 
    references FACULTY (fid)  
    ); 
CREATE TABLE ENROLLED ( 
    cnum VARCHAR(6), 
    sid NUMERIC(6) NOT NULL, 
    PRIMARY KEY (cnum,sid), 
    FOREIGN KEY (sid) 
     REFERENCES STUDENT (sid), 
     FOREIGN KEY (sid) 
     REFERENCES FACULTY (fid), 
     FOREIGN KEY (cnum) 
     REFERENCES CLASS (cnum)   
    ); 
    alter table ENROLLED 
    add foreign key (sid) 
    references STUDENT (sid); 

Answer 1

SELECT `sid`, `cid` 
FROM (`STUDENT` INNER JOIN `ENROLLED` ON `STUDENT`.`sid` = `ENROLLED`.`sid`) 
    INNER JOIN `CLASS` ON `ENROLLED`.`cnum` = `CLASS`.`cnum` 
GROUP BY `ENROLLED`.`cid` 
HAVING 
    `CLASS`.`room` = '115' OR 
    COUNT(DISTINCT `STUDENT`.`sid`) >= 5 

Answer 2

たぶんこのような何か：

SELECT 
    * 
FROM 
    CLASS 
WHERE 
    CLASS.room='115' 
    OR 
    (
     SELECT 
      COUNT(*) 
     FROM 
      ENROLLED 
      JOIN STUDENT 
       ON ENROLLED.sid=STUDENT.sid 
     WHERE 
      ENROLLED.cnum=CLASS.cnum 
    )>=5