복잡한 검색 연습 문서의 문제 3 풀이 코드다.

-- 실행: docker exec -i vault-pg psql -U postgres -v ON_ERROR_STOP=1 -q -f - < 이 파일
-- 70.복잡한 검색 연습 p3 (Q3-1, Q3-2, Q3-3)
-- PostgreSQL 16에서 실행한다. 모든 단언을 통과하면 마지막 줄에 ALL CHECKS PASSED가 나온다.
SET client_min_messages TO WARNING;
DROP SCHEMA IF EXISTS complex_retrieval_practice_p3 CASCADE;
CREATE SCHEMA complex_retrieval_practice_p3;
SET search_path TO complex_retrieval_practice_p3;

-- COMPANY 스키마와 상태 (Elmasri 그림 5.5~5.7).
-- WORKS_ON.Hours에는 NOT NULL을 걸지 않았다. 상태에 (888665555, 20, NULL)이 있다.
-- 서로 가리키는 외래 키(EMPLOYEE.Dno <-> DEPARTMENT.Mgr_ssn)는 커밋할 때 검사하도록 미뤘다.
CREATE TABLE EMPLOYEE (Fname VARCHAR(15) NOT NULL, Minit CHAR, Lname VARCHAR(15) NOT NULL, Ssn CHAR(9) NOT NULL,
  Bdate DATE, Address VARCHAR(30), Sex CHAR, Salary DECIMAL(10,2), Super_ssn CHAR(9), Dno INT NOT NULL,
  PRIMARY KEY (Ssn), FOREIGN KEY (Super_ssn) REFERENCES EMPLOYEE(Ssn) DEFERRABLE INITIALLY DEFERRED);
CREATE TABLE DEPARTMENT (Dname VARCHAR(15) NOT NULL, Dnumber INT NOT NULL, Mgr_ssn CHAR(9) NOT NULL, Mgr_start_date DATE,
  PRIMARY KEY (Dnumber), UNIQUE (Dname),
  FOREIGN KEY (Mgr_ssn) REFERENCES EMPLOYEE(Ssn) DEFERRABLE INITIALLY DEFERRED);
ALTER TABLE EMPLOYEE ADD FOREIGN KEY (Dno) REFERENCES DEPARTMENT(Dnumber) DEFERRABLE INITIALLY DEFERRED;
CREATE TABLE DEPT_LOCATIONS (Dnumber INT NOT NULL, Dlocation VARCHAR(15) NOT NULL,
  PRIMARY KEY (Dnumber, Dlocation), FOREIGN KEY (Dnumber) REFERENCES DEPARTMENT(Dnumber));
CREATE TABLE PROJECT (Pname VARCHAR(15) NOT NULL, Pnumber INT NOT NULL, Plocation VARCHAR(15), Dnum INT NOT NULL,
  PRIMARY KEY (Pnumber), UNIQUE (Pname), FOREIGN KEY (Dnum) REFERENCES DEPARTMENT(Dnumber));
CREATE TABLE WORKS_ON (Essn CHAR(9) NOT NULL, Pno INT NOT NULL, Hours DECIMAL(3,1),
  PRIMARY KEY (Essn, Pno), FOREIGN KEY (Essn) REFERENCES EMPLOYEE(Ssn), FOREIGN KEY (Pno) REFERENCES PROJECT(Pnumber));
CREATE TABLE DEPENDENT (Essn CHAR(9) NOT NULL, Dependent_name VARCHAR(15) NOT NULL, Sex CHAR, Bdate DATE,
  Relationship VARCHAR(8),
  PRIMARY KEY (Essn, Dependent_name), FOREIGN KEY (Essn) REFERENCES EMPLOYEE(Ssn));
BEGIN;
INSERT INTO EMPLOYEE VALUES
 ('John','B','Smith','123456789','1965-01-09','731 Fondren, Houston, TX','M',30000,'333445555',5),
 ('Franklin','T','Wong','333445555','1955-12-08','638 Voss, Houston, TX','M',40000,'888665555',5),
 ('Alicia','J','Zelaya','999887777','1968-01-19','3321 Castle, Spring, TX','F',25000,'987654321',4),
 ('Jennifer','S','Wallace','987654321','1941-06-20','291 Berry, Bellaire, TX','F',43000,'888665555',4),
 ('Ramesh','K','Narayan','666884444','1962-09-15','975 Fire Oak, Humble, TX','M',38000,'333445555',5),
 ('Joyce','A','English','453453453','1972-07-31','5631 Rice, Houston, TX','F',25000,'333445555',5),
 ('Ahmad','V','Jabbar','987987987','1969-03-29','980 Dallas, Houston, TX','M',25000,'987654321',4),
 ('James','E','Borg','888665555','1937-11-10','450 Stone, Houston, TX','M',55000,NULL,1);
INSERT INTO DEPARTMENT VALUES ('Research',5,'333445555','1988-05-22'),
 ('Administration',4,'987654321','1995-01-01'), ('Headquarters',1,'888665555','1981-06-19');
INSERT INTO DEPT_LOCATIONS VALUES (1,'Houston'),(4,'Stafford'),(5,'Bellaire'),(5,'Sugarland'),(5,'Houston');
INSERT INTO PROJECT VALUES ('ProductX',1,'Bellaire',5),('ProductY',2,'Sugarland',5),('ProductZ',3,'Houston',5),
 ('Computerization',10,'Stafford',4),('Reorganization',20,'Houston',1),('Newbenefits',30,'Stafford',4);
INSERT INTO WORKS_ON VALUES ('123456789',1,32.5),('123456789',2,7.5),('666884444',3,40.0),('453453453',1,20.0),
 ('453453453',2,20.0),('333445555',2,10.0),('333445555',3,10.0),('333445555',10,10.0),('333445555',20,10.0),
 ('999887777',30,30.0),('999887777',10,10.0),('987987987',10,35.0),('987987987',30,5.0),('987654321',30,20.0),
 ('987654321',20,15.0),('888665555',20,NULL);
INSERT INTO DEPENDENT VALUES ('333445555','Alice','F','1986-04-05','Daughter'),
 ('333445555','Theodore','M','1983-10-25','Son'),('333445555','Joy','F','1958-05-03','Spouse'),
 ('987654321','Abner','M','1942-02-28','Spouse'),('123456789','Michael','M','1988-01-04','Son'),
 ('123456789','Alice','F','1988-12-30','Daughter'),('123456789','Elizabeth','F','1967-05-05','Spouse');
COMMIT;

-- Q3-1
DO $$ BEGIN
  ASSERT (SELECT string_agg(Fname || ' ' || Minit || ' ' || Lname, ',') FROM EMPLOYEE
          WHERE Dno = (SELECT Dno FROM EMPLOYEE WHERE Salary = (SELECT MAX(Salary) FROM EMPLOYEE))) = 'James E Borg',
         'Q3-1이 James E Borg가 아니다';
END $$;

-- Q3-2 틀리기 쉬운 판: = 뒤의 안쪽 질의가 2행이라 PostgreSQL 16은 오류를 낸다 (SQLite는 첫 행만 써서 3명)
DO $$ DECLARE ok boolean := false; BEGIN
  BEGIN
    EXECUTE $q$ SELECT Fname, Minit, Lname FROM EMPLOYEE
                WHERE Super_ssn = (SELECT Ssn FROM EMPLOYEE WHERE Super_ssn = '888665555') $q$;
  EXCEPTION WHEN cardinality_violation THEN ok := true;   -- more than one row returned by a subquery used as an expression
  END;
  ASSERT ok, 'Q3-2 = 판이 오류를 내지 않았다';
END $$;

-- 고친 판: IN, 그리고 자기 조인
DO $$ BEGIN
  ASSERT (SELECT string_agg(Lname, ',' ORDER BY Lname) FROM EMPLOYEE
          WHERE Super_ssn IN (SELECT Ssn FROM EMPLOYEE WHERE Super_ssn = '888665555'))
         = 'English,Jabbar,Narayan,Smith,Zelaya', 'Q3-2 IN 판이 5명이 아니다';
  ASSERT (SELECT string_agg(E.Lname, ',' ORDER BY E.Lname)
          FROM EMPLOYEE AS E JOIN EMPLOYEE AS S ON E.Super_ssn = S.Ssn
          WHERE S.Super_ssn = '888665555') = 'English,Jabbar,Narayan,Smith,Zelaya', 'Q3-2 자기 조인 판이 5명이 아니다';
  ASSERT (SELECT COUNT(*) FROM EMPLOYEE
          WHERE Super_ssn IN (SELECT Ssn FROM EMPLOYEE WHERE Super_ssn = '88866555')) = 0, '8자리 Ssn 판이 0행이 아니다';
END $$;

-- Q3-3
DO $$ BEGIN
  ASSERT (SELECT string_agg(Lname, ',' ORDER BY Lname) FROM EMPLOYEE
          WHERE Salary - 10000 >= (SELECT MIN(Salary) FROM EMPLOYEE)) = 'Borg,Narayan,Wallace,Wong',
         'Q3-3이 Borg, Narayan, Wallace, Wong이 아니다';
END $$;

SELECT 'ALL CHECKS PASSED';