Chapter 5 SQL
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Chapter 5
SQL
Agenda
• Data Manipulation Language (DML)– SELECT– Union compatible operations– Update database
SQL DML - SELECT
• SELECT [DISTINCT|ALL] {* | [col-expr [AS newname]][,...]
FROM table-name [alias] [,...] [WHERE condition] [GROUP BY colm [, colm] [HAVING condition]] ORDER BY colm [, colm]
SQL DML - SELECT
• SELECT attributes (or calculations: +, -, /, *)
FROM relation
• SELECT DISTINCT attributes FROM relation
Examples
• SELECT stunameFROM student;
• SELECT stuid, stuname, creditFROM student;
• SELECT stuid, stuname, credit+10FROM student;
• SELECT DISTINCT majorFROM student;
SQL DML - SELECT
• SELECT attributes (or * wild card) FROM relation WHERE condition
Examples
• SELECT *FROM student;
• SELECT stuname, major, creditFROM student
WHERE stuid = ‘S114’;
• SELECT *FROM faculty
WHERE dept = ‘MIS’;
SELECT - WHERE condition
• AND OR• NOT IN• NOT IN BETWEEN• IS NULL IS NOT NULL• SOME ALL• LIKE '%' multiple characters • LIKE ‘_’ single character
Examples• SELECT *
FROM facultyWHERE dept = ‘MIS’
AND rank = ‘full professor’;
• SELECT *FROM faculty
WHERE dept = ‘MIS’ OR rank = ‘full professor’;
• SELECT *FROM faculty
WHERE dept = ‘MIS’ NOT rank = ‘full professor’;
• SELECT *FROM class
WHERE room LIKE ‘B_S%’;
• SELECT *FROM class
WHERE room NOT LIKE ‘BUS%’;
• SELECT productid, productnameFROM inventory
WHERE onhand BETWEEN 50 and 100;
• SELECT companyid, companynameFROM companyWHERE companyname BETWEEN
‘G’ AND ‘K’;
• SELECT productid, productnameFROM inventoryWHERE onhand NOT BETWEEN
50 and 100;
• SELECT companyid, companynameFROM companyWHERE companyname NOT
BETWEEN ‘G’ AND ‘K’;
• SELECT facnameFROM facultyWHERE dept IN (‘MIS’, ‘ACT’);
• SELECT facnameFROM facultyWHERE rank NOT IN (‘assistant’, ‘lecture’);
• SELECT customernameFROM customerWHERE emailadd IS NOT NULL;
• SELECT customernameFROM customer
WHERE creditlimit IS NULL;
SELECT - aggregate functions
• COUNT (*)• COUNT• SUM• AVG• MIN• MAX
Examples
• SELECT COUNT(*)FROM student;
• SELECT COUNT(major)FROM student;
• SELECT COUNT(DISTINCT major)FROM student;
• SELECT COUNT(stuid), SUM(credit), AVG(credit), MAX(credit),
MIN(credit)FROM student;
• How many different guests have made bookings for August 2004?
• Hotel (hotelno, hotelname, city)
• Room (roomno, hotelno, type, price)
• Booking (hotelno, guestno, datefrom, dateto, roomno)
• Guest (guestno, guestname, guestaddress)
• How many different guests have made bookings for August 2004?
•
• SELECT COUNT(DISTINCT guestno)
• FROM booking
• WHERE (datefrom <= ‘8/31/04’) AND
• (dateto >= ‘8/1/04’);
SELECT - GROUP
• GROUP BY• HAVING
Examples
• SELECT major, AVG(credit)FROM student
GROUP BY major
• SELECT course#, COUNT(stuid)FROM enrollment
GROUP BY course#
Examples
• SELECT major, AVG(credit)FROM studentGROUP BY major
HAVING COUNT(*) > 2;• SELECT course#, COUNT(stuid)
FROM enrollmentGROUP BY course#
HAVING COUNT(*) > 2;
• SELECT major, AVG(credit)FROM student
WHERE major IN (‘mis’, ‘act’) GROUP BY major
HAVING COUNT(*) > 2;
SELECT - ORDER BY
• ORDER BY• ORDER BY ... DESC
Examples
• SELECT facname, rank FROM faculty
ORDER BY facname;
• SELECT facname, rank FROM faculty
ORDER BY rank DESC, facname;
SELECT - JOIN Tables
• Multiple tables in FROM clause• MUST have join conditions!!!
Examples
• SELECT stuname, gradeFROM student, enrollmentWHERE student.stuid =
enrollment.stuid;
• SELECT enrollment.course#, stuname, major
FROM class, enrollment, studentWHERE class.course# =
enrollment.course#AND enrollment.stuid = student.stuidAND facid = ‘F114’
ORDER BY enrollment.course#;
OUTER JOINS
• RIGHT JOIN• LEFT JOIN• FULL JOIN• Appending (+) to the optional column
(null) in the join condition (Oracle)
Examples
• SELECT f.facid, f.facname, c.course# FROM class c, faculty fWHERE c.facid (+) = f.facid
ORDER BY f.facname; (rightouterjoin)
• SELECT s.stuname, major, gradeFROM student s, enrollment eWHERE s.stuid = e.stuid (+)
ORDER BY s.stuname; (leftouterjoin)
• SELECT f.facid, f.facname, c.course# FROM class c RIGHT JOIN faculty fON c.facid = f.facid
ORDER BY f.facname; (rightouterjoin)• SELECT s.stuname, major, grade
FROM student s LEFT JOIN enrollment e
ON s.stuid = e.stuid
ORDER BY s.stuname; (leftouterjoin)
• SELECT f.facid, f.facname, c.course#, c.room
FROM class c, faculty fWHERE c.facid (+) =
f.facid (+) ORDER BY f.facname; (fullouterjoin)
• SELECT f.facid, f.facname, c.course#, c.room
FROM class c FULL JOIN faculty f ON c.facid = f.facid
ORDER BY f.facname; (fullouterjoin)
Example
• List the number of room in each hotel in London.
• Hotel (hotelno, hotelname, city)
• Room (roomno, hotelno, type, price)
• Booking (hotelno, guestno, datefrom, dateto, roomno)
• Guest (guestno, guestname, guestaddress)
Example
• List the number of room in each hotel in London.
• SELECT r.hotelno, COUNT(roomno)• FROM room r, hotel h• WHERE r.hotelno=h.hotelno AND• city = ‘London'• GROUP BY hotelno;
Union Compatible Operations
• UNION
• MINUS or EXCEPT
• INTERSECT
• Union compatible operator [ALL] [CORRESPONGIND][BY column,..] (ALL includes duplicated rows in the result)
• Used between SELECT commands
Examples
• SELECT stuid, stunameFROM sacstudent
UNIONSELECT stuid, stuname
FROM chicostudent;• SELECT *• FROM sacstudentUNION CORRESPONGIND BY stuid, stuname
SELECT *FROM chicostudent;
• SELECT stuid, stunameFROM sacstudent
EXCEPT
SELECT stuid, stunameFROM chicostudent;
• (SELECT stuid, stunameFROM sacstudent)
INTERSECT
(SELECT stuid, stunameFROM chicostudent)ORDER BY 2;
Column Alias
• SELECT prodid, prodname,(salesprice - goodofcost) profit
FROM productORDER BY prodid;
• SELECT prodid, prodname,(salesprice - goodofcost) AS
profit FROM productORDER BY prodid;
SUBQUERY
• SELECT stuid, stuname, credit
• FROM student
• WHERE credit > (SELECT AVG(credit)
• FROM student);
• SELECT stuid, stuname, major
• FROM student
• WHERE stuid IN (SELECT stuid
• FROM enrollment);
• SELECT stuid, stuname, major
• FROM student
• WHERE stuid NOT IN (SELECT stuid
• FROM enrollment)
Example
• What is the most commonly booked room type for all hotels in London?
• Hotel (hotelno, hotelname, city)• Room (roomno, hotelno, type, price)• Booking (hotelno, guestno, datefrom,
dateto, roomno)• Guest (guestno, guestname, guestaddress)
• What is the most commonly booked room type for all hotels in London?
• • SELECT type, MAX(y)• FROM• (SELECT type, COUNT(type) AS y • FROM booking b, hotel h, room r• WHERE r.roomno = b.roomno AND r.hotelno = b.hotelno AND• b.hotelno = h.hotelno AND • city = 'London' • GROUP BY type)• GROUP BY type;
EXIST
• SELECT s.stuname, majorFROM student s
WHERE EXIST(SELECT *
FROM enrollment e WHERE
s.stuid = e.stuid);
NOT EXIST
• SELECT s.stuname, majorFROM student s
WHERE NOT EXIST(SELECT *
FROM enrollment e WHERE
s.stuid = e.stuid);
SOME
• SELECT stuid, stuname, major, credit
• FROM student
• WHERE credit > SOME (SELECT credit
• FROM student
• WHERE major=‘mis’);
ANY
• SELECT stuid, stuname, major, credit
• FROM student
• WHERE credit > ANY (SELECT credit
• FROM student
• WHERE major=‘mis’);
ALL
• SELECT stuid, stuname, major, credit
• FROM student
• WHERE credit > ALL (SELECT credit
• FROM student
• WHERE major=‘mis’);
• What is the lost income from unoccupied rooms at the Grosvenor Hotel today?
• Hotel (hotelno, hotelname, city)• Room (roomno, hotelno, type, price)• Booking (hotelno, guestno, datefrom, dateto, roomno)
• Guest (guestno, guestname, guestaddress)
• What is the lost income from unoccupied rooms at the Grosvenor Hotel today?
• SELECT SUM(price)• FROM room r, hotel h• WHERE r.hotelno = h.hotelno AND• h.hotelname = 'Grosvenor’ AND• r.roomno NOT IN• (SELECT roomno FROM booking b, hotel h• WHERE b.hotelno = h.hotelno AND• (datefrom <= ‘SYSTEM DATE’• AND dateto >= ‘SYSTEM DATE’) AND• h.hotelname = 'Grosvenor');
• What is the lost income from unoccupied rooms at each hotel today?
• Hotel (hotelno, hotelname, city)• Room (roomno, hotelno, type, price)• Booking (hotelno, guestno, datefrom,
dateto, roomno)• Guest (guestno, guestname, guestaddress)
• What is the lost income from unoccupied rooms at each hotel today?
• SELECT h.hotelno, SUM(price)• FROM room r• WHERE roomno NOT EXIST• (SELECT *• FROM booking b, hotel h, room r• WHERE b.hotelno = h.hotelno AND• r.roomno = b.roomno AND• r.hotelno = b.hotelno AND• datefrom <= ‘SYSTEM DATE’ AND• dateto >= ‘SYSTEM DATE’ )• GROUP BY hotelno;
SQL DML - UPDATE, INSERT, DELETE
• INSERT INTO table-name [(colm [, colm])] VALUES (const [, const] )
• UPDATE table-name SET colm = expr [colm = expr] ... [WHERE condition]
• DELETE FROM table-name [WHERE condition]
Examples
• INSERT INTO student
(stuid, stuname, major, credit)
VALUES (‘S114’, ‘Grace’, ‘MIS’, 60);
• UPDATE student
SET major = ‘Database’, credit = 100
WHERE stuid = ‘S114’;
• UPDATE student
SET major = ‘MIS’;
• DELETE FROM student
WHERE stuid = ‘S114’;
• DELETE FROM student;
Points To Remember
• Data Manipulation Language (DML)– SELECT– Union compatible operations– Update database
Assignment
• Review chapter 1 – 5, appendix C
• Read chapter 6
• Homework Assignment– 5.7 – 5.28 (not 5.18)– Due date:
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