Oracle sql MINUS 帮助：显示教授特定课程但没有资格教授特定课程的教师

Question

第一 table

CREATE TABLE qualified (
    facultyid integer NOT NULL,
    courseid character varying(16) NOT NULL,
    datequalified character varying(16),
    dq2 date,
    CONSTRAINT qualified_pkey PRIMARY KEY (facultyid, courseid)
);

INSERT INTO qualified VALUES (3467, 'ISM 4212', to_date('9/1995', 'MM/YYYY'), date '1995-09-01');
INSERT INTO qualified VALUES (4756, 'ISM 3112', to_date('9/1991', 'MM/YYYY'), date '1991-09-01');
INSERT INTO qualified VALUES (2143, 'ISM 3113', to_date('9/1988', 'MM/YYYY'), date '1988-09-01');
INSERT INTO qualified VALUES (4756, 'ISM 3113', to_date('9/1991', 'MM/YYYY'), date '1991-09-01');
INSERT INTO qualified VALUES (2143, 'ISM 3112', to_date('9/1988', 'MM/YYYY'), date '1988-09-01');
INSERT INTO qualified VALUES (3467, 'ISM 4930', to_date('9/1996', 'MM/YYYY'), date '1996-09-01');

第 2 table:

CREATE TABLE faculty (
    facultyid integer NOT NULL,
    facultyname character varying(25),
    CONSTRAINT faculty_pkey PRIMARY KEY (facultyid)
);

INSERT INTO faculty VALUES (2143, 'Birkin');
INSERT INTO faculty VALUES (3467, 'Berndt');
INSERT INTO faculty VALUES (4756, 'Collins');

查询：是否有教师有资格教授 ISM 4212 而没有资格教授 ISM 4930？

我试过的查询：

SELECT q.facultyid, facultyname, q.courseid
FROM qualified q, faculty fa
WHERE q.facultyid = fa.facultyid AND courseid = 'ISM 4212'
MINUS
SELECT q.facultyid, facultyname, q.courseid
FROM qualified q, faculty fa
WHERE q.facultyid = fa.facultyid AND courseid = 'ISM 4930';

显示：3467 Berndt ISM 4212

而不是：NOTHING/No 结果。

Answer 1

从 select 子句中删除以下内容解决了问题：

q.courseid

Oracle sql MINUS 帮助：显示教授特定课程但没有资格教授特定课程的教师

Oracle sql MINUS help: Show faculty that teaches a specific AND not qualified to teach a specific course

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