Print multiple rows in some order as different columns - sql

Question

/* Note: on update/delete, no action (restriction) is
the default. (SQL Server & Oracle) */
CREATE TABLE Faculty (
FacNo CHAR(11) NOT NULL,
FacFirstName VARCHAR(30) NOT NULL,
FacLastName VARCHAR(30) NOT NULL,
FacCity VARCHAR(30) NOT NULL,
FacState CHAR(2) NOT NULL,
FacDept CHAR(6) NULL,
FacRank CHAR(4) NULL,
FacSalary DECIMAL(10,2) NULL,
FacSupervisor CHAR(11) NULL,
FacHireDate DATETIME NULL,
FacZipCode CHAR(10) NOT NULL,
CONSTRAINT FacultyPK PRIMARY KEY (FacNo),
CONSTRAINT SupervisorFK FOREIGN KEY (FacSupervisor) REFERENCES Faculty )
go
/* Note: on update cascade for FacSupervisor caused the following error
in SQL Server 2004:
Introducing FOREIGN KEY CONSTRAINT 'SupervisorFK' on table 'Faculty'
may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION
or ON UPDATE NO ACTION, or modify other FOREIGN KEY CONSTRAINTs.
*/
CREATE TABLE Course (
CourseNo CHAR(6) NOT NULL,
CrsDesc VARCHAR(50) NOT NULL,
CrsUnits INTEGER NULL,
CONSTRAINT CoursePK PRIMARY KEY (CourseNo) )
go
CREATE TABLE Offering (
OfferNo INTEGER NOT NULL,
CourseNo CHAR(6) NOT NULL,
OffTerm CHAR(6) NOT NULL,
OffYear INTEGER NOT NULL,
OffLocation VARCHAR(30) NULL,
OffTime VARCHAR(10) NULL,
FacNo CHAR(11) NULL,
OffDays CHAR(4) NULL,
CONSTRAINT OfferingPK PRIMARY KEY (OfferNo),
CONSTRAINT CourseFK FOREIGN KEY (CourseNo) REFERENCES Course,
CONSTRAINT FacultyFK FOREIGN KEY (FacNo) REFERENCES Faculty )
go
CREATE TABLE Student (
StdNo CHAR(11) NOT NULL,
StdFirstName VARCHAR(30) NOT NULL,
StdLastName VARCHAR(30) NOT NULL,
StdCity VARCHAR(30) NOT NULL,
StdState CHAR(2) NOT NULL,
StdZip CHAR(10) NOT NULL,
StdMajor CHAR(6) NULL,
StdClass CHAR(2) NULL,
StdGPA DECIMAL(3,2) NULL,
CONSTRAINT StudentPk PRIMARY KEY (StdNo) )
go
CREATE TABLE Enrollment (
OfferNo INTEGER NOT NULL,
StdNo CHAR(11) NOT NULL,
EnrGrade DECIMAL(3,2) NULL,
CONSTRAINT EnrollmentPK PRIMARY KEY (OfferNo, StdNo),
CONSTRAINT OfferingFK FOREIGN KEY (OfferNo) REFERENCES Offering
ON DELETE CASCADE
ON UPDATE CASCADE,
CONSTRAINT StudentFK FOREIGN KEY (StdNo) REFERENCES Student
ON DELETE CASCADE
ON UPDATE CASCADE )
go
INSERT INTO Faculty
VALUES ('543210987','VICTORIA','EMMANUEL','BOTHELL','WA','MS','PROF',120000.00,NULL,'4/15/2005','98011-2242')
go
INSERT INTO Faculty
VALUES ('765432109','NICKI','MACON','BELLEVUE','WA','FIN','PROF',65000.00,NULL,'4/11/2006','98015-9945')
go
INSERT INTO Faculty
VALUES ('654321098','LEONARD','FIBON','SEATTLE','WA','MS','ASSC',70000.00,'543210987','5/1/2003','98121-0094')
go
INSERT INTO Faculty
VALUES ('098765432','LEONARD','VINCE','SEATTLE','WA','MS','ASST',35000.00,'654321098','4/10/2004','98111-9921')
go
INSERT INTO Faculty
VALUES ('876543210','CRISTOPHER','COLAN','SEATTLE','WA','MS','ASST',40000.00,'654321098','3/1/2008','98114-1332')
go
INSERT INTO Faculty
VALUES ('987654321','JULIA','MILLS','SEATTLE','WA','FIN','ASSC',75000.00,'765432109','3/15/2009','98114-9954')
go
INSERT INTO Course
VALUES ('FIN300','FUNDAMENTALS OF FINANCE',4)
go
INSERT INTO Course
VALUES ('FIN450','PRINCIPLES OF INVESTMENTS',4)
go
INSERT INTO Course
VALUES ('FIN480','CORPORATE FINANCE',4)
go
INSERT INTO Course
VALUES ('IS320','FUNDAMENTALS OF BUSINESS PROGRAMMING',4)
go
INSERT INTO Course
VALUES ('IS460','SYSTEMS ANALYSIS',4)
go
INSERT INTO Course
VALUES ('IS470','BUSINESS DATA COMMUNICATIONS',4)
go
INSERT INTO Course
VALUES ('IS480','FUNDAMENTALS OF DATABASE MANAGEMENT',4)
go
INSERT INTO Offering
VALUES (1111,'IS320','SUMMER',2017,'BLM302','10:30:00',NULL,'MW')
go
INSERT INTO Offering
VALUES (1234,'IS320','FALL',2016,'BLM302','10:30:00','098765432','MW')
go
INSERT INTO Offering
VALUES (2222,'IS460','SUMMER',2016,'BLM412','13:30:00',NULL,'TTH')
go
INSERT INTO Offering
VALUES (3333,'IS320','SPRING',2017,'BLM214','8:30:00','098765432','MW')
go
INSERT INTO Offering
VALUES (4321,'IS320','FALL',2016,'BLM214','15:30:00','098765432','TTH')
go
INSERT INTO Offering
VALUES (4444,'IS320','WINTER',2017,'BLM302','15:30:00','543210987','TTH')
go
INSERT INTO Offering
VALUES (5555,'FIN300','WINTER',2017,'BLM207','8:30:00','765432109','MW')
go
INSERT INTO Offering
VALUES (5678,'IS480','WINTER',2017,'BLM302','10:30:00','987654321','MW')
go
INSERT INTO Offering
VALUES (5679,'IS480','SPRING',2017,'BLM412','15:30:00','876543210','TTH')
go
INSERT INTO Offering
VALUES (6666,'FIN450','WINTER',2017,'BLM212','10:30:00','987654321','TTH')
go
INSERT INTO Offering
VALUES (7777,'FIN480','SPRING',2017,'BLM305','13:30:00','765432109','MW')
go
INSERT INTO Offering
VALUES (8888,'IS320','SUMMER',2017,'BLM405','13:30:00','654321098','MW')
go
INSERT INTO Offering
VALUES (9876,'IS460','SPRING',2017,'BLM307','13:30:00','654321098','TTH')
go
INSERT INTO Student
VALUES ('123456789','HOMER','WELLS','SEATTLE','WA','98121-1111','IS','FR',3.00)
go
INSERT INTO Student
VALUES ('124567890','BOB','NORBERT','BOTHELL','WA','98011-2121','FIN','JR',2.70)
go
INSERT INTO Student
VALUES ('234567890','CANDY','KENDALL','TACOMA','WA','99042-3321','ACCT','JR',3.50)
go
INSERT INTO Student
VALUES ('345678901','WALLY','KENDALL','SEATTLE','WA','98123-1141','IS','SR',2.80)
go
INSERT INTO Student
VALUES ('456789012','JOE','ESTRADA','SEATTLE','WA','98121-2333','FIN','SR',3.20)
go
INSERT INTO Student
VALUES ('567890123','MARIAH','DODGE','SEATTLE','WA','98114-0021','IS','JR',3.60)
go
INSERT INTO Student
VALUES ('678901234','TESS','DODGE','REDMOND','WA','98116-2344','ACCT','SO',3.30)
go
INSERT INTO Student
VALUES ('789012345','ROBERTO','MORALES','SEATTLE','WA','98121-2212','FIN','JR',2.50)
go
INSERT INTO Student
VALUES ('876543210','CRISTOPHER','COLAN','SEATTLE','WA','98114-1332','IS','SR',4.00)
go
INSERT INTO Student
VALUES ('890123456','LUKE','BRAZZI','SEATTLE','WA','98116-0021','IS','SR',2.20)
go
INSERT INTO Student
VALUES ('901234567','WILLIAM','PILGRIM','BOTHELL','WA','98113-1885','IS','SO',3.80)
go
INSERT INTO Enrollment
VALUES (1234,'123456789',3.30)
go
INSERT INTO Enrollment
VALUES (1234,'234567890',3.50)
go
INSERT INTO Enrollment
VALUES (1234,'345678901',3.20)
go
INSERT INTO Enrollment
VALUES (1234,'456789012',3.10)
go
INSERT INTO Enrollment
VALUES (1234,'567890123',3.80)
go
INSERT INTO Enrollment
VALUES (1234,'678901234',3.40)
go
INSERT INTO Enrollment
VALUES (4321,'123456789',3.50)
go
INSERT INTO Enrollment
VALUES (4321,'124567890',3.20)
go
INSERT INTO Enrollment
VALUES (4321,'789012345',3.50)
go
INSERT INTO Enrollment
VALUES (4321,'876543210',3.10)
go
INSERT INTO Enrollment
VALUES (4321,'890123456',3.40)
go
INSERT INTO Enrollment
VALUES (4321,'901234567',3.10)
go
INSERT INTO Enrollment
VALUES (5555,'123456789',3.20)
go
INSERT INTO Enrollment
VALUES (5555,'124567890',2.70)
go
INSERT INTO Enrollment
VALUES (5678,'123456789',3.20)
go
INSERT INTO Enrollment
VALUES (5678,'234567890',2.80)
go
INSERT INTO Enrollment
VALUES (5678,'345678901',3.30)
go
INSERT INTO Enrollment
VALUES (5678,'456789012',3.40)
go
INSERT INTO Enrollment
VALUES (5678,'567890123',2.60)
go
INSERT INTO Enrollment
VALUES (5679,'123456789',2.00)
go
INSERT INTO Enrollment
VALUES (5679,'124567890',3.70)
go
INSERT INTO Enrollment
VALUES (5679,'678901234',3.30)
go
INSERT INTO Enrollment
VALUES (5679,'789012345',3.80)
go
INSERT INTO Enrollment
VALUES (5679,'890123456',2.90)
go
INSERT INTO Enrollment
VALUES (5679,'901234567',3.10)
go
INSERT INTO Enrollment
VALUES (6666,'234567890',3.10)
go
INSERT INTO Enrollment
VALUES (6666,'567890123',3.60)
go
INSERT INTO Enrollment
VALUES (7777,'876543210',3.40)
go
INSERT INTO Enrollment
VALUES (7777,'890123456',3.70)
go
INSERT INTO Enrollment
VALUES (7777,'901234567',3.40)
go
INSERT INTO Enrollment
VALUES (9876,'124567890',3.50)
go
INSERT INTO Enrollment
VALUES (9876,'234567890',3.20)
go
INSERT INTO Enrollment
VALUES (9876,'345678901',3.20)
go
INSERT INTO Enrollment
VALUES (9876,'456789012',3.40)
go
INSERT INTO Enrollment
VALUES (9876,'567890123',2.60)
go
INSERT INTO Enrollment
VALUES (9876,'678901234',3.30)
go
INSERT INTO Enrollment
VALUES (9876,'901234567',4.00)
go
Schema for example.
Get all the faculty numbers (FacNo) and last names (FacLastName) of two different faculty who offered courses in the same offering year (OffYear). There must be no duplicates in the output.
*Note: For instance, if both P1 Smith and P2 Peters offered courses in 2021, then [P1, Smith, P2, Peters] (or [P2, Peters, P1, Smith], but not both) must be selected. So, the output must look like this:
FacNo FacLastName FacNo FacLastName
===== =========== ===== ===========
P1 Smith P2 Peters
... ... ... ...
===== =========== ===== ===========*
I am trying to do something like this and I can't even think where to start? How do I approach this problem?
I tried something like this
SELECT f1.FacNo, f1.FacLastName
FROM Offering o1
INNER JOIN Faculty f1 on o1.FacNo = f1.FacNo
INNER JOIN Offering o2 on o1.OffYear = o2.OffYear

Answer 1

You are on the right track. Joining the Offering table twice on the OffYear correctly gets you the combinations of courses in the same year. Since you want the names of the two faculty members, you also need to join the Faculty table twice:
SELECT f1.FacNo, f1.FacLastName, f2.FacNo, f2.FacLastName
FROM Offering o1
INNER JOIN Faculty f1
on o1.FacNo = f1.FacNo
INNER JOIN Offering o2
on o2.OffYear = o1.Offyea
INNER JOIN Faculty f2
on o2.FacNo = f2.FacNo
This will however include exact duplicate rows (e.g. when two faculty members had two courses in the same year), combinations of faculty members with themselves and duplicate combinations of names in reverse order (both [P1, Smith, P2, Peters] and [P2, Peters, P1, Smith]).
To get rid of the exact duplicates, use SELECT DISTINCT instead of SELECT. The other two problems can be easily fixed with one WHERE condition: By limiting results so that the first member's FacNo is smaller than the other's, unwanted combinations are filtered out.
SELECT DISTINCT f1.FacNo, f1.FacLastName, f2.FacNo, f2.FacLastName
FROM Offering o1
INNER JOIN Faculty f1
on o1.FacNo = f1.FacNo
INNER JOIN Offering o2
on o2.OffYear = o1.Offyear
INNER JOIN Faculty f2
on o2.FacNo = f2.FacNo
WHERE f1.FacNo < f2.FacNo
See this dB<>fiddle.