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SQL Workshop
University of California, Berkeley
School of Information
IS 257: Database Management
IS 257 – Fall 2015
2015-09-10 SLIDE 1
Announcements
IS 257 – Fall 2015
2015-09-10 SLIDE 2
Lecture Outline
• Review
– The Relational Model Revisited
– Introduction to SQL
• How to Connect to MySQL
– Via phpMyAdmin
– Via Terminal and MySQL program
• Installing the Diveshop Database
• Running queries
– Via phpMyAdmin
– Via MySQL on Terminal
IS 257 – Fall 2015
2015-09-10 SLIDE 3
SQL
• Structured Query Language
• Used for both Database Definition,
Modification and Querying
• Basic language is standardized across
relational DBMS’s. Each system may
have proprietary extensions to standard.
• Relational Calculus combines Restrict,
Project and Join operations in a single
command. SELECT.
IS 257 – Fall 2015
2015-09-10 SLIDE 4
SELECT
• Syntax:
SELECT [DISTINCT] attr1, attr2,…, attr3
FROM rel1 r1, rel2 r2,… rel3 r3 WHERE
condition1 {AND | OR} condition2 ORDER
BY attr1 [DESC], attr3 [DESC]
IS 257 – Fall 2015
2015-09-10 SLIDE 5
SELECT
• Syntax:
SELECT a.`Author Name`, b.Title FROM
authors a, books b WHERE a.Authorid =
b.Authorid ORDER BY a.`Author name` ;
authors
pubid
1
2
3
4
books
Book ID
1
2
3
4
5
IS 257 – Fall 2015
Title
pubid
Introductio
The history
New stuff ab
Another title
And yet more
2
4
3
2
1
Author id
1
2
3
4
5
Book ID
pubname
Harper
Addison
Oxford
Que
Authorid
1
2
3
4
5
Author name
Smith
Wynar
Jones
Duncan
Applegate
Subid
1
2
3
4
4
2
1
3
2
3
Subid
Subject
1 cataloging
2 history
3 stuff
2015-09-10 SLIDE 6
SELECT Conditions
•
•
•
•
•
•
= equal to a particular value
>= greater than or equal to a particular value
> greater than a particular value
<= less than or equal to a particular value
<> not equal to a particular value
LIKE “%term%” (may be other wild cards in
other systems)
• IN (“opt1”, “opt2”,…,”optn”)
• BETWEEN val1 AND val2
• IS NULL
IS 257 – Fall 2015
2015-09-10 SLIDE 7
Relational Algebra Restrict using SELECT
• Syntax:
SELECT * WHERE condition1 {AND | OR}
condition2;
IS 257 – Fall 2015
2015-09-10 SLIDE 8
Relational Algebra Projection using SELECT
• Syntax:
SELECT [DISTINCT] attr1, attr2,…, attr3
FROM rel1 r1;
IS 257 – Fall 2015
2015-09-10 SLIDE 9
Relational Algebra Join using SELECT
• Syntax:
SELECT * FROM rel1 r1, rel2 r2 WHERE
r1.linkattr = r2.linkattr ;
A1 B1
A2 B1
A3 B2
IS 257 – Fall 2015
B1 C1
B2 C2
B3 C3
(Natural
or Inner)
Join
A1 B1 C1
A2 B1 C1
A3 B2 C2
2015-09-10 SLIDE 10
DiveShop ER Diagram
Customer
No
DiveCust
1
Destination
Name
Destination
no
Customer
No
ShipVia
n
Dest
n
1
DiveOrds
n
1
ShipVia
ShipVia
1
Destination
no
Site No
1
n
Site No
BioSite
Species
No
1
Destination
n
Sites
Order
No
n
1
1/n
ShipWrck
Order
No
DiveItem
n
Item
No
n
Site No
1
Species
No
BioLife
IS 257 – Fall 2015
1
DiveStok
Item
No
2015-09-10 SLIDE 11
Sorting
• SELECT BIOLIFE.Common_Name,
BIOLIFE.Length_cm
FROM BIOLIFE
ORDER BY BIOLIFE.Length_cm DESC;
IS 257 – Fall 2015
2015-09-10 SLIDE 12
Subqueries
• SELECT SITES.Site_Name,
SITES.Destination_no FROM SITES
WHERE sites.Destination_no
IN (SELECT Destination_no from DEST
where Avg_Temp_F >= 78);
• Can be used as a form of JOIN
IS 257 – Fall 2015
2015-09-10 SLIDE 13
Aggregate Functions
•
•
•
•
•
•
Count
Avg
SUM
MAX
MIN
Many others are available in different
systems
IS 257 – Fall 2015
2015-09-10 SLIDE 14
Using Aggregate functions
• SELECT attr1, Sum(attr2) AS name
FROM tab1, tab2 ...
GROUP BY attr1, attr3 HAVING condition;
IS 257 – Fall 2015
2015-09-10 SLIDE 15
Using an Aggregate Function
Implied Joins
• SELECT DIVECUST.Name,
Sum(Rental_Price*Qty) AS Total
FROM DIVECUST, DIVEORDS, DIVEITEM,
DIVESTOK WHERE DIVECUST.Customer_No =
DIVEORDS.Customer_No AND
DIVEORDS.Order_No = DIVEITEM.Order_No
AND DIVEITEM.Item_No = DIVESTOK.Item_No
GROUP BY DIVECUST.Name
HAVING ((DIVECUST.Name) LIKE
‘%Jazdzewski%’);
IS 257 – Fall 2015
2015-09-10 SLIDE 16
Using an Aggregate Function
Explicit Join statements
• SELECT DIVECUST.Name,
Sum(Rental_Price*Qty) AS Total
FROM (DIVECUST INNER JOIN DIVEORDS ON
DIVECUST.Customer_No =
DIVEORDS.Customer_No) INNER JOIN
DIVEITEM ON DIVEORDS.Order_No =
DIVEITEM.Order_No INNER JOIN DIVESTOK ON
DIVEITEM.Item_No = DIVESTOK.Item_No
GROUP BY DIVECUST.Name
HAVING ((DIVECUST.Name) LIKE
‘%Jazdzewski%’);
IS 257 – Fall 2015
2015-09-10 SLIDE 17
GROUP BY
• SELECT DEST.Destination_Name,
Count(*) AS Expr1
FROM DEST INNER JOIN DIVEORDS
ON DEST.Destination_Name =
DIVEORDS.Destination
GROUP BY DEST.Destination_Name
HAVING ((Count(*))>1);
• Provides a list of Destinations with the
number of orders going to that destination
IS 257 – Fall 2015
2015-09-10 SLIDE 18
Connecting to phpMyAdmin
• We will step through Kevin Heard’s
phpMyAdmin tutorial (there is a link from
the Assignment 1 page)
• Follow along on your laptop…
• Note: phpMyAdmin has changed versions
since the tutorial was originally written, but
most things should work about the same
IS 257 – Fall 2015
2015-09-10 SLIDE 19