Related
I have 2 tables that look like this where I want to query how many scholarships (from Tuition table) each department (from Student table) has distributed:
I am thinking a join is necessary but am not sure how to do so.
Create tables
create table students (
sid int auto_increment primary key,
name varchar(100),
email varchar(100),
department varchar(100)
);
create table tutions (
id int auto_increment primary key,
sid int,
cost int,
scholarships int,
duedate timestamp default current_timestamp
);
Sample data
insert into students (name, email, department)
values
('John Doe', 'john#abc.xyz', 'B'),
('Jane Doe', 'jane#abc.xyz', 'A'),
('Jack Doe', 'jack#abc.xyz', 'C'),
('Jill Doe', 'jill#abc.xyz', 'B');
insert into tutions (sid, cost, scholarships)
values
(1, 1000, 2),
(2, 1000, 1),
(3, 1000, 7),
(4, 1000, 2);
Query (department-wise total scholarships)
SELECT department, sum(scholarships) as scholarships
FROM students s
JOIN tutions t ON s.sid = t.sid
GROUP BY department
Output
Running SQL Fiddle
Not sure It's something you want? And not sure scholarships is a number or name of scholarship? So I doubt it's a name as varchar string type.
### dummy record
CREATE TABLE students (
psu_id INTEGER PRIMARY KEY,
firstname VARCHAR NOT NULL,
lastname VARCHAR NOT NULL,
email VARCHAR NOT NULL,
department VARCHAR NOT NULL
);
CREATE TABLE tuition (
tuition_id INTEGER PRIMARY KEY,
student_id INTEGER NOT NULL,
semeter_cost INTEGER NOT NULL,
scholarships VARCHAR NOT NULL,
due_date DATE NOT NULL
);
INSERT INTO students VALUES (1, 'John', 'Hello', 'Jonh#email.com', 'Engineering');
INSERT INTO students VALUES (2, 'Bella', 'Fuzz', 'Bella#email.com', 'Computer');
INSERT INTO students VALUES (3, 'Sunny', 'World', 'Sunny#email.com', 'Science');
INSERT INTO tuition VALUES (1, 1, 4000, 'first_class_en', '2022-05-09' );
INSERT INTO tuition VALUES (2, 2, 3000, 'nobel', '2022-05-09' );
INSERT INTO tuition VALUES (3, 3, 5000, 'hackathon', '2022-05-09' );
INSERT INTO tuition VALUES (4, 1, 4500, 'second_class_en', '2022-05-09' );
-----------------
### query
SELECT s.department, count(t.scholarships)
FROM students s
JOIN tuition t
ON s.psu_id = t.student_id
GROUP BY s.department
### output
department, total_scholarships
Computer|1
Engineering|2
Science|1
I am trying to figure out a query for this question: for each major, list the number of students, minimum GPA, maximum GPA, average GPA, minimum age, maximum age, and average age. (Show GPA with 2 decimal points, age with no decimal points. You may find it useful to create a view with one of the previous queries for this one.)
This is the script to create the table for SQL!
REM drop all the tables. Note that you need to drop the
REM dependent table first before dropping the base tables.
drop table Reg;
drop table Student;
drop table Course;
REM Now create all the tables.
create table Student
(
sid char(10) primary key,
sname varchar(20) not null,
gpa float,
major char(10),
dob DATE
);
create table Course
(
cno char(10) primary key,
cname varchar(20) not null,
credits int,
dept char(10)
);
create table Reg
(
sid references Student(sid) on delete cascade,
cno references Course(cno) on delete cascade,
grade char(2),
primary key (sid, cno)
);
REM Now insert all the rows.
insert into Student values ('111', 'Joe', 3.5 , 'MIS', '01-AUG-2000');
insert into Student values ('222', 'Jack', 3.4 , 'MIS', '12-JAN-1999');
insert into Student values ('333', 'Jill', 3.2 , 'CS', '15-MAY-1998');
insert into Student values ('444', 'Mary', 3.7 , 'CS', '17-DEC-2001');
insert into Student values ('555', 'Peter', 3.8 , 'CS', '19-MAR-1999');
insert into Student values ('666', 'Pat', 3.9, 'Math', '31-MAY-2000');
insert into Student values ('777', 'Tracy', 4.0, 'Math', '18-JUL-1997');
insert into Course values ('c101', 'intro', 3 , 'CS');
insert into Course values ('m415', 'database', 4 , 'Bus');
insert into Course values ('m215', 'programming', 4 , 'Bus');
insert into Course values ('a444', 'calculus', 3 , 'Math');
insert into Reg values ('111', 'c101', 'A');
insert into Reg values ('111', 'm215', 'B');
insert into Reg values ('111', 'm415', 'A');
insert into Reg values ('222', 'm215', 'A');
insert into Reg values ('222', 'm415', 'B');
insert into Reg values ('333', 'c101', 'A');
insert into Reg values ('444', 'm215', 'C');
insert into Reg values ('444', 'm415', 'B');
insert into Reg values ('555', 'c101', 'B');
insert into Reg values ('555', 'm215', 'A');
insert into Reg values ('555', 'm415', 'A');
insert into Reg values ('666', 'c101', 'A');
This is what I have so far:
SELECT major,
count(distinct SID) as students,
round(min(gpa), 2),
round(max(gpa), 2),
round(avg(gpa), 2),
trunc(min(sysdate - dob)/365) as min_age,
trunc(max(sysdate - dob)/365) as max_age,
trunc(avg(sysdate - dob)/365) as avg_age,
FROM Student
GROUP BY MAJOR;
According to your input I've made a query that I belive will show you the results. (It was kind hard to read the tables the way you posted it). The syntax may differ according to your DBMS (SQL Server, MySQL, REdshift, Postgres, etc)
Here is the query:
SELECT major,
COUNT(*) as students,
ROUND(MIN(gpa), 2) as min_gpa,
ROUND(MAX(gpa), 2) as max_gpa,
ROUND(AVG(gpa), 2) as avg_gpa,
MIN(DATEDIFF(year, current_date, dob)) as min_age,
MAX(DATEDIFF(year, current_date, dob)) as max_age,
AVG(DATEDIFF(year, current_date, dob)) as avg_date
FROM students st left join Course co on co.dept = st.major
GROUP BY major
Your query is completely fine (just remove comma(,) after avg_age.
SELECT major,
count(distinct SID) as students,
round(min(gpa), 2) as MinGPA,
round(max(gpa), 2) as MaxGPA,
round(avg(gpa), 2) as AvgGPA,
round(min(sysdate - dob)/365,0) as min_age,
round(max(sysdate - dob)/365,0) as max_age,
round(avg(sysdate - dob)/365,0) as avg_age
FROM Student
GROUP BY MAJOR;
You can also use months_between() with floor() to get the same result:
select * from student;
SELECT major,
count(distinct SID) as students,
round(min(gpa), 2) as MinGPA,
round(max(gpa), 2) as MaxGPA,
round(avg(gpa), 2) as AvgGPA,
floor(min(months_between(trunc((sysdate)), dob)) /12) as min_age,
floor(max(months_between(trunc((sysdate)), dob)) /12) as max_age,
floor(avg(months_between(trunc((sysdate)), dob)) /12) as avg_age
FROM Student
GROUP BY MAJOR;
So I'm working on a SQL and I keep getting errors and I have triple checked it and still haven't come up with a reason as to why the queries aren't showing up correctly. I'm using Microsoft SQL Server. These are the errors that I'm currently getting:
Msg 1767, Level 16, State 0, Line 2
Foreign key 'FK_PatientID' references invalid table 'Patient'.
Msg 1750, Level 16, State 0, Line 2
Could not create constraint. See previous errors.
Msg 208, Level 16, State 1, Line 2
Invalid object name 'TreatmentDetails'.
Code:
IF EXISTS (SELECT name FROM sys.databases WHERE name = N'Hospital')
DROP DATABASE [Hospital]
GO
CREATE DATABASE [Hospital]
GO
USE Hospital
GO
CREATE TABLE [dbo].[Physician]
(
PhysicianID INTEGER NOT NULL,
FirstName VARCHAR(30) NOT NULL,
LastName VARCHAR(30) NOT NULL,
Specialty VARCHAR(30) NOT NULL,
GraduationDate DATE NOT NULL,
CONSTRAINT [PK_PhysicianID] PRIMARY KEY (PhysicianID)
);
GO
CREATE TABLE [dbo].[TreatmentDetails]
(
TreatmentID INTEGER NOT NULL,
PhysicianID INTEGER NOT NULL,
PatientID INTEGER NOT NULL,
StartDateTime DATE NOT NULL,
EndDateTime DATE NULL,
Results VARCHAR(30),
CONSTRAINT [PK_TreatmentID] PRIMARY KEY (TreatmentID),
CONSTRAINT [FK_PhysicianID] FOREIGN KEY (PhysicianID) REFERENCES Physician(PhysicianID),
CONSTRAINT [FK_PatientID] FOREIGN KEY (PatientID) REFERENCES Patient(PatientID),
);
GO
CREATE TABLE [dbo].[Patient]
(
PatientID INTEGER NOT NULL,
FirstName VARCHAR(30) NOT NULL,
LastName VARCHAR(30) NOT NULL,
DateOfBirth DATE NOT NULL,
CONSTRAINT [PK_PatientID] PRIMARY KEY (PatientID),
);
GO
CREATE TABLE [dbo].[AdmissionDate]
(
AdmissionID INTEGER NOT NULL,
PhysicianID INTEGER NOT NULL,
PatientID INTEGER NOT NULL,
AdmissionDate DATE NOT NULL,
DischargeDate DATE NULL,
CONSTRAINT [PK_AdmissionID] PRIMARY KEY (AdmissionID),
CONSTRAINT [FK_PhysicianID] FOREIGN KEY (PhysicianID) REFERENCES Physician(PhysicianID),
CONSTRAINT [FK_PatientID] FOREIGN KEY (PatientID) REFERENCES Patient(PatientID),
);
GO
INSERT INTO TreatmentDetails VALUES (1, 12345, 1234, '2014-4-5', NULL, 'NOT DONE')
INSERT INTO TreatmentDetails VALUES (2, 12346, 1235, '2013-5-6', NULL, 'NOT DONE')
INSERT INTO TreatmentDetails VALUES (3, 12347, 1236, '2012-7-8', '2014-9-10', 'Patient finished')
INSERT INTO TreatmentDetails VALUES (4, 12348, 1237, '2011-9-10', '2013-11-12', 'Patient finished')
INSERT INTO TreatmentDetails VALUES (5, 12349, 1238, '2010-11-12', NULL, 'NOT DONE')
INSERT INTO Physician VALUES (12345, 'Will', 'Smith', 'Surgeon', '2014-5-9');
INSERT INTO Physician VALUES (12346, 'Jim', 'Carey', 'Pediatrictian', '2013-2-4');
INSERT INTO Physician VALUES (12347, 'Adam', 'Sandler', 'Immunologist', '2012-6-12');
INSERT INTO Physician VALUES (12348, 'Seth', 'Rogan', 'Neurologist', '2010-9-19');
INSERT INTO Physician VALUES (12349, 'James', 'Bond', 'Dermatologist', '2011-5-2');
INSERT INTO Patient VALUES (1234, 'Christopher', 'Thompson', '1989-7-9');
INSERT INTO Patient VALUES (1235, 'Mac', 'Miller', '1970-9-5');
INSERT INTO Patient VALUES (1236, 'Abraham', 'Lincoln', '1988-1-22');
INSERT INTO Patient VALUES (1237, 'George', 'Washington', '1965-2-8');
INSERT INTO Patient VALUES (1238, 'Franklin', 'Roosevelt', '1992-5-19');
INSERT INTO AdmissionDate VALUES (001, 12345, 1234,'2014-2-9', NULL);
INSERT INTO AdmissionDate VALUES (002, 12346, 1235, '2014-12-8', '2014-15-9');
INSERT INTO AdmissionDate VALUES (003, 12347, 1236,'2014-3-7', '2014-4-9');
INSERT INTO AdmissionDate VALUES (004, 12348, 1237, '2014-8-6', NULL);
INSERT INTO AdmissionDate VALUES (005, 12349, 1238, '2014-5-5', NULL);
GO
USE Hospital
SELECT * FROM Physician
SELECT * FROM Patient
SELECT * FROM AdmissionDate
SELECT * FROM TreatmentDetails
SELECT Patient.PatientID, Patient.FirstName, Patient.LastName, Patient.DateOfBirth, AdmissionDate.AdmissionDate, AdmissionDate.DischargeDate, Physician.Specialty
FROM Patient, AdmissionDate, Physician
WHERE AdmissionDate IS NOT NULL
ORDER BY Patient.LastName, Patient.FirstName, AdmissionDate.AdmissionDate
SELECT Physician.PhysicianID, Physician.FirstName, Physician.LastName, Patient.PatientID, Patient.FirstName, Patient.LastName, TreatmentDetails.TreatmentID, TreatmentDetails.StartDateTime, TreatmentDetails.EndDateTime, TreatmentDetails.Results
FROM Physician, Patient, TreatmentDetails
WHERE TreatmentDetails.EndDateTime IS NULL
ORDER BY TreatmentDetails.StartDateTime, Physician.LastName, Patient.LastName
SELECT Physician.PhysicianID, Physician.FirstName, Physician.LastName, Patient.PatientID, Patient.FirstName, Patient.LastName, TreatmentDetails.TreatmentID, TreatmentDetails.StartDateTime, TreatmentDetails.EndDateTime, TreatmentDetails.Results
FROM Physician, Patient, TreatmentDetails
WHERE TreatmentDetails.EndDateTime IS NOT NULL
ORDER BY TreatmentDetails.StartDateTime, Physician.LastName, Patient.LastName
You have incorrect order of creating tables.
You are creating foreign keys with same name in different tables.
You are inserting data in tables in incorrect order.
You have provided incorrect date format. Default format is YYYY-MM-DD
and you provide INSERT INTO AdmissionDate VALUES (002, 12346, 1235, '2014-12-8', '2014-15-9'); 2014-15-9 this is to change.
Here is working script:
USE master
IF EXISTS (SELECT name FROM sys.databases WHERE name = N'Hospital')
DROP DATABASE [Hospital]
GO
CREATE DATABASE [Hospital]
GO
USE Hospital
GO
CREATE TABLE [dbo].[Physician]
(
PhysicianID INTEGER NOT NULL,
FirstName VARCHAR(30) NOT NULL,
LastName VARCHAR(30) NOT NULL,
Specialty VARCHAR(30) NOT NULL,
GraduationDate DATE NOT NULL,
CONSTRAINT [PK_PhysicianID] PRIMARY KEY (PhysicianID)
);
GO
CREATE TABLE [dbo].[Patient]
(
PatientID INTEGER NOT NULL,
FirstName VARCHAR(30) NOT NULL,
LastName VARCHAR(30) NOT NULL,
DateOfBirth DATE NOT NULL,
CONSTRAINT [PK_PatientID] PRIMARY KEY (PatientID),
);
GO
CREATE TABLE [dbo].[TreatmentDetails]
(
TreatmentID INTEGER NOT NULL,
PhysicianID INTEGER NOT NULL,
PatientID INTEGER NOT NULL,
StartDateTime DATE NOT NULL,
EndDateTime DATE NULL,
Results VARCHAR(30),
CONSTRAINT [PK_TreatmentDetails_TreatmentID] PRIMARY KEY (TreatmentID),
CONSTRAINT [FK_TreatmentDetails_PhysicianID] FOREIGN KEY (PhysicianID) REFERENCES Physician(PhysicianID),
CONSTRAINT [FK_TreatmentDetails_PatientID] FOREIGN KEY (PatientID) REFERENCES Patient(PatientID),
);
GO
CREATE TABLE [dbo].[AdmissionDate]
(
AdmissionID INTEGER NOT NULL,
PhysicianID INTEGER NOT NULL,
PatientID INTEGER NOT NULL,
AdmissionDate DATE NOT NULL,
DischargeDate DATE NULL,
CONSTRAINT [PK_AdmissionDate_AdmissionID] PRIMARY KEY (AdmissionID),
CONSTRAINT [FK_AdmissionDate_PhysicianID] FOREIGN KEY (PhysicianID) REFERENCES Physician(PhysicianID),
CONSTRAINT [FK_AdmissionDate_PatientID] FOREIGN KEY (PatientID) REFERENCES Patient(PatientID),
);
GO
INSERT INTO Physician VALUES (12345, 'Will', 'Smith', 'Surgeon', '2014-5-9');
INSERT INTO Physician VALUES (12346, 'Jim', 'Carey', 'Pediatrictian', '2013-2-4');
INSERT INTO Physician VALUES (12347, 'Adam', 'Sandler', 'Immunologist', '2012-6-12');
INSERT INTO Physician VALUES (12348, 'Seth', 'Rogan', 'Neurologist', '2010-9-19');
INSERT INTO Physician VALUES (12349, 'James', 'Bond', 'Dermatologist', '2011-5-2');
INSERT INTO Patient VALUES (1234, 'Christopher', 'Thompson', '1989-7-9');
INSERT INTO Patient VALUES (1235, 'Mac', 'Miller', '1970-9-5');
INSERT INTO Patient VALUES (1236, 'Abraham', 'Lincoln', '1988-1-22');
INSERT INTO Patient VALUES (1237, 'George', 'Washington', '1965-2-8');
INSERT INTO Patient VALUES (1238, 'Franklin', 'Roosevelt', '1992-5-19');
INSERT INTO TreatmentDetails VALUES (1, 12345, 1234, '2014-4-5', NULL, 'NOT DONE')
INSERT INTO TreatmentDetails VALUES (2, 12346, 1235, '2013-5-6', NULL, 'NOT DONE')
INSERT INTO TreatmentDetails VALUES (3, 12347, 1236, '2012-7-8', '2014-9-10', 'Patient finished')
INSERT INTO TreatmentDetails VALUES (4, 12348, 1237, '2011-9-10', '2013-11-12', 'Patient finished')
INSERT INTO TreatmentDetails VALUES (5, 12349, 1238, '2010-11-12', NULL, 'NOT DONE')
INSERT INTO AdmissionDate VALUES (001, 12345, 1234,'2014-2-9', NULL);
INSERT INTO AdmissionDate VALUES (002, 12346, 1235, '2014-12-8', '2014-9-15');
INSERT INTO AdmissionDate VALUES (003, 12347, 1236,'2014-3-7', '2014-4-9');
INSERT INTO AdmissionDate VALUES (004, 12348, 1237, '2014-8-6', NULL);
INSERT INTO AdmissionDate VALUES (005, 12349, 1238, '2014-5-5', NULL);
GO
USE Hospital
SELECT * FROM Physician
SELECT * FROM Patient
SELECT * FROM AdmissionDate
SELECT * FROM TreatmentDetails
SELECT Patient.PatientID, Patient.FirstName, Patient.LastName, Patient.DateOfBirth, AdmissionDate.AdmissionDate, AdmissionDate.DischargeDate, Physician.Specialty
FROM Patient, AdmissionDate, Physician
WHERE AdmissionDate IS NOT NULL
ORDER BY Patient.LastName, Patient.FirstName, AdmissionDate.AdmissionDate
SELECT Physician.PhysicianID, Physician.FirstName, Physician.LastName, Patient.PatientID, Patient.FirstName, Patient.LastName, TreatmentDetails.TreatmentID, TreatmentDetails.StartDateTime, TreatmentDetails.EndDateTime, TreatmentDetails.Results
FROM Physician, Patient, TreatmentDetails
WHERE TreatmentDetails.EndDateTime IS NULL
ORDER BY TreatmentDetails.StartDateTime, Physician.LastName, Patient.LastName
SELECT Physician.PhysicianID, Physician.FirstName, Physician.LastName, Patient.PatientID, Patient.FirstName, Patient.LastName, TreatmentDetails.TreatmentID, TreatmentDetails.StartDateTime, TreatmentDetails.EndDateTime, TreatmentDetails.Results
FROM Physician, Patient, TreatmentDetails
WHERE TreatmentDetails.EndDateTime IS NOT NULL
ORDER BY TreatmentDetails.StartDateTime, Physician.LastName, Patient.LastName
Using Table aliases, list the first name, last name and start date of students enrolled on the java fundamentals module:
I am having some trouble when running the query below.
SELECT stu.StudFName, stu.StudLName, enrol.StartDate
From Student stu
INNER JOIN Enrolment enrol
ON stu.StudID = enrol.StudID
INNER JOIN Module mod
ON enrol.ModCode = mod.ModCode
WHERE mod.ModName = 'Java Fundamentals'
Structure:
CREATE TABLE Student
(StudID INTEGER PRIMARY KEY,
StudFName VARCHAR(10) NOT NULL,
StudLName VARCHAR(10) NOT NULL,
DoB DATE NOT NULL,
Sex CHAR(1) NOT NULL CHECK (Sex IN ('M', 'F')),
Email VARCHAR(30) UNIQUE);
CREATE TABLE Staff
(StaffID INTEGER PRIMARY KEY,
Title VARCHAR(4) CHECK (Title IN ('Prof', 'Dr', 'Mr', 'Mrs', 'Miss')),
StaffFName VARCHAR(10) NOT NULL,
StaffLName VARCHAR(10) NOT NULL,
Email VARCHAR(30) UNIQUE,
Department VARCHAR(25) DEFAULT 'Not Assigned',
Extension INTEGER CHECK (Extension BETWEEN 0001 AND 9999));
CREATE TABLE Module
(ModCode CHAR(4) PRIMARY KEY,
ModName VARCHAR(25) NOT NULL,
ModCredits INTEGER NOT NULL CHECK (ModCredits IN (15, 30, 45, 60)),
ModLevel CHAR(3) NOT NULL CHECK (ModLevel IN ('UG1', 'UG2', 'UG3', 'MSc')),
ModLeader INTEGER NOT NULL,
Foreign Key (ModLeader) REFERENCES Staff (StaffID));
CREATE TABLE Enrolment
(ModCode CHAR(4) NOT NULL,
StudID INTEGER NOT NULL,
StartDate DATE NOT NULL,
PRIMARY KEY (ModCode, StudID),
Foreign Key (StudID) REFERENCES Student (StudID),
Foreign Key (ModCode) REFERENCES Module (ModCode));
The answer is... there is no trouble with your query.
It works just fine.
Check here
INSERT INTO Student (StudID, StudFName, StudLName, DoB, Sex, Email) VALUES
(1, 'Jack', 'Black', TO_DATE('2015/01/01', 'yyyy/mm/dd'), 'M', 'jack#email.com');
INSERT INTO Student (StudID, StudFName, StudLName, DoB, Sex, Email) VALUES
(2, 'Andrew', 'Wiggin', TO_DATE('2015/01/01', 'yyyy/mm/dd'), 'M', 'andrew#email.com');
INSERT INTO Student (StudID, StudFName, StudLName, DoB, Sex, Email) VALUES
(3, 'Bob', 'Marley', TO_DATE('2015/01/01', 'yyyy/mm/dd'), 'M', 'bob#email.com');
INSERT INTO Staff (StaffID, Title, StaffFName, StaffLName, Email, Extension) VALUES
(1, 'Prof', 'Joe', 'Smith', 'stuff#emal.com', 0001);
INSERT INTO Module (ModCode, ModName, ModCredits, ModLevel, ModLeader) VALUES
(1, 'Java Fundamentals', 30, 'UG1', 1);
INSERT INTO Module (ModCode, ModName, ModCredits, ModLevel, ModLeader) VALUES
(2, 'C# Fundamentals', 15, 'UG2', 1);
INSERT INTO Enrolment (ModCode, StudID, StartDate) VALUES
(1, 1, TO_DATE('2015/01/01', 'yyyy/mm/dd'));
INSERT INTO Enrolment (ModCode, StudID, StartDate) VALUES
(1, 2, TO_DATE('2015/01/02', 'yyyy/mm/dd'));
INSERT INTO Enrolment (ModCode, StudID, StartDate) VALUES
(2, 3, TO_DATE('2015/01/03', 'yyyy/mm/dd'));
-------------------------------------------------------------
SELECT stu.StudFName, stu.StudLName, enrol.StartDate
From Student stu
INNER JOIN Enrolment enrol ON stu.StudID = enrol.StudID
INNER JOIN Module mod ON enrol.ModCode = mod.ModCode
WHERE mod.ModName = 'Java Fundamentals'
Result
STUDFNAME STUDLNAME STARTDATE
----------------------------------------
Jack Black January, 01 2015
Andrew Wiggin January, 02 2015
Here are my tables and insert values:
create table student (
LastName varchar(40),
FirstName varchar(40),
SID number(5),
SSN number(9),
Career varchar(4),
Program varchar(10),
City varchar(40),
Started number(4),
primary key (SID),
unique(SSN)
);
create table enrolled (
StudentID number(5),
CourseID number(4),
Quarter varchar(6),
Year number(4),
primary key (StudentID, CourseID),
foreign key (StudentID) references student(SID),
foreign key (CourseID) references course(CID)
);
insert into student
values ( 'Brennigan', 'Marcus', 90421, 987654321, 'UGRD', 'COMP-GPH', 'Evanston', 2001 );
insert into student
values ( 'Patel', 'Deepa', 14662, null, 'GRD', 'COMP-SCI', 'Evanston', 2003 );
insert into student
values ( 'Snowdon', 'Jonathan', 08871, 123123123, 'GRD', 'INFO-SYS', 'Springfield', 2005 );
insert into student
values ( 'Starck', 'Jason', 19992, 789789789, 'UGRD', 'INFO-SYS', 'Springfield', 2003 );
insert into student
values ( 'Johnson', 'Peter', 32105, 123456789, 'UGRD', 'COMP-SCI', 'Chicago', 2004 );
insert into student
values ( 'Winter', 'Abigail', 11035, 111111111, 'GRD', 'PHD', 'Chicago', 2003 );
insert into student
values ( 'Patel', 'Prakash', 75234, null, 'UGRD', 'COMP-SCI', 'Chicago', 2001 );
insert into student
values ( 'Snowdon', 'Jennifer', 93321, 321321321, 'GRD', 'COMP-SCI', 'Springfield', 2004 );
insert into enrolled
values (11035, 1020, 'Fall', 2005);
insert into enrolled
values (11035, 1092, 'Fall', 2005);
insert into enrolled
values (11035, 8772, 'Spring', 2006);
insert into enrolled
values (75234, 3201, 'Winter', 2006);
insert into enrolled
values (08871, 1092, 'Fall', 2005);
insert into enrolled
values (90421, 8772, 'Spring', 2006);
insert into enrolled
values (90421, 2987, 'Spring', 2006);
I have the following query:
SELECT e.studentid
FROM enrolled e
FULL OUTER JOIN student s ON e.studentid = s.sid
WHERE ((e.quarter = 'Fall') OR (e.quarter = 'Spring'))
GROUP BY e.studentid
HAVING count(e.studentid) = 1;
But this only returns
8871
This should return
8871
90421
The goal of this query is: List students who were enrolled in at least one course in Fall quarter or at least one course in the Spring quarter, but not both. You will have to add a couple of rows to test your query.
Any help would be appreciated it. Thanks.
give this a try,
SELECT a.SID
FROM student a
INNER JOIN enrolled b
ON a.SID = b.StudentID
WHERE b.quarter IN ('Fall', 'Spring')
GROUP BY a.SID
HAVING COUNT(DISTINCT b.quarter) = 1
SELECT e.studentid
FROM enrolled e
WHERE e.quarter IN ('Spring', 'Fall')
GROUP BY
e.studentid
HAVING COUNT(DISTINCT quarter) = 1;
90421 is enrolled in two different courses during spring, that's why your original query counted it twice.
You need to count seasons, not enrollments.
There are two records for the student id - 90421 hence count will return 2