Disclaimer:

• All images such as logos, photos, etc. used in this presentation are the property of their respective copyright owners and are used

here for educational purposes only

• Some material adapted from: Sorger, Stephan. “Marketing Analytics: Strategic Models and Metrics. Admiral Press. 2013.

Introduction to

Data Science and Analytics

Stephan Sorger www.StephanSorger.com

Unit 6A. SQL: Overview and Coding SQL Commands

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 1

Outline/ Learning Objectives

Topic Description

Introduction Languages to query (get data from) databases

Vendors Top 3 vendors in market

RDBMS Relational Database Management Systems

Commands Litany of various SQL Commands, with examples

Resources Learning more about SQL

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 2

Database Query: Introduction

Category Description

SQL Structured Query Language (for this class: ANSI SQL)

Programming language for accessing RDBMS

RDBMS Relational Database Management System

Two Parts Data Definition Language: Syntax for defining data structures

Data Manipulation Language: Syntax for selecting, inserting

deleting, and updating data in databases

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 3

Structured Query Language

Data Definition Language Data Manipulation Language

Category Description

Top 3 Top 3 Database engines

Oracle Target market: Fortune 500 Corporations

Oracle Database, Enterprise Edition, $10,450

Microsoft Target market: Small – Mid Sized Businesses

Microsoft SQL Server, Enterprise Edition, $14,256

MySQL Target market: Small – Mid-Sized Businesses; Education

Open Source, Free

Available for Mac and PC

Others… Sybase, MS Access, Ingres, etc.

Database Query: Introduction

Oracle price list, Oct. 2015: http://www.oracle.com/us/corporate/pricing/technology-price-list-070617.pdf

Microsoft price list, Dec. 2015: http://www.microsoft.com/en-us/server-cloud/products/sql-server/purchasing.aspx

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 4

RDBMS Database Example

Row: Record

Primary Key: Column with 100% unique entries

similar to Social Security Number (‘Engine’ column will not work; duplicate entries)

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 5

Table: Jazzstars

last first id age city state

Armstrong Louis 11111 70 New Orleans Louisiana

Baker Chet 11112 58 Yale Oklahoma

Basie Count 11113 80 Red Bank New Jersey

Blakey Art 11114 32 Pittsburgh Pennsylvania

Brown Clifford 11115 25 Wilmington Delaware

Brubeck Dave 11116 91 Concord California

Calloway Cab 11117 86 Rochester New York

Carter Benny 11118 96 New York New York

Cole NatKing 11119 45 Montgomery Alabama

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 6

Sample Table: Jazzstars

SELECT

Topic Description

SELECT Used to query database and retrieve chosen data

Syntax SELECT “column1” [, “column2”, etc ] [ optional ]

FROM “tablename” [ WHERE “condition” ] ;

Conditionals = Equal

> Greater than; < Less than

>= Greater than or equal; <= Less than or equal

<> Not equal to

LIKE pattern matching operator…startswith%, %endswith

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 7

SELECT

Topic Description

SELECT Used to query database and retrieve chosen data

Syntax SELECT “column1” [, “column2”, etc ] [ optional ]

FROM “tablename” [ WHERE “condition” ] ;

Conditionals = Equal

> Greater than; < Less than

>= Greater than or equal; <= Less than or equal

<> Not equal to

LIKE pattern matching operator…startswith%, %endswith

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 8

SELECT age FROM Jazzstars; Returns age column

SELECT * FROM Jazzstars WHERE first=‘Count’; Returns Count Basie ( * = wildcard )

SELECT first, last FROM Jazzstars WHERE first LIKE ‘Ba%’; Returns Chet Baker, Count Basie

SELECT first, last FROM Jazzstars WHERE last LIKE ‘%k’; Returns Dave Brubeck

Format at Most Companies

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 9

SELECT age FROM Jazzstars;

Command in CAPS

Database element in lowercase Database name in Mixed/ lower

Format at Most Companies

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 10

WARNING:

Not following format can be

instantly-fireable offense

at some companies

CODING HAZARD

Troubleshooting nightmare

Similar to leaving hammer

on top of ladder in construction

SAFETY HAZARD

Enforcement nightmare

CREATE TABLE

Topic Description

CREATE TABLE Used to create a new table

Syntax CREATE TABLE “tablename”

(“column1” “datatype” [constraint], “column2”…); [ ] = optional

Datatype char(size) Fixed-length character string

varchar(size) Variable-length character string

number(size) Numerical value, integer

number(size,d) Numerical value, real, with d digits in decimal

date Date value

Constraint Rule associated with column: “Not null”; “Primary key”

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 11

CREATE TABLE

Topic Description

CREATE TABLE Used to create a new table

Syntax CREATE TABLE “tablename”

(“column1” “datatype” [constraint], “column2”…); [ ] = optional

Datatype char(size) Fixed-length character string

varchar(size) Variable-length character string

number(size) Numerical value, integer

number(size,d) Numerical value, real, with d digits in decimal

date Date value

Constraint Rule associated with column: “Not null”; “Primary key”

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 12

CREATE TABLE Jazzstars (last varchar(15), first varchar(15), id number (10),

age number (3), city varchar (20), state varchar (20));

INSERT INTO (table)

Topic Description

INSERT INTO Insert a row of data into existing table

Syntax INSERT INTO “tablename” (columnlist)

VALUES (‘valuestoinsert’);

Purpose Adding a new record into table, using same structure

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 13

INSERT INTO Jazzstars (last, first, id, age, city, state)

VALUES (‘Davis’, ‘Miles’; ‘11120’, ’65’, ‘Alton’, ‘Illinois’);

Table: Jazzstars

last first id age city state

Armstrong Louis 11111 70 New Orleans Louisiana

Baker Chet 11112 58 Yale Oklahoma

Basie Count 11113 80 Red Bank New Jersey

Blakey Art 11114 32 Pittsburgh Pennsylvania

Brown Clifford 11115 25 Wilmington Delaware

Brubeck Dave 11116 91 Concord California

Calloway Cab 11117 86 Rochester New York

Carter Benny 11118 96 New York New York

Cole NatKing 11119 45 Montgomery Alabama

Davis Miles 11120 65 Alton Illinois

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 14

New record

UPDATE

Topic Description

UPDATE Change records matching specified criteria

Syntax UPDATE “tablename”

SET “columnname” = “newvalue” [, “nextcolumn” = “newvalue2”]

WHERE “columnname”

AND|OR “value” [AND|OR “column” AND|OR “value”];

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 15

UPDATE SFPeninsula_Phonebook SET zipcode = 94028 WHERE prefix = 851;

UPDATE SFPeninsula_Phonebook SET lastname = ‘Marriedname’, prefix=555, suffix=1212

WHERE lastname = ‘Maidenname’;

UPDATE employeedatabase SET age=age+1

WHERE lastname= ‘Boy’ AND firstname = ‘Birthday’;

DELETE FROM

Topic Description

DELETE FROM Eliminate records (rows) from tables

Syntax DELETE FROM “tablename”

AND|OR “value” [AND|OR “column” AND|OR “value”];

[ ] = optional

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 16

DELETE FROM Jazzstars;

Table: Jazzstars

Last First ID Age City State

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 17

Oops; Just deleted everything; I hope I made a backup

Never mind, I hope I keep my job

DELETE FROM

Topic Description

DELETE FROM Eliminate records (rows) from tables

Syntax DELETE FROM “tablename”

AND|OR “value” [AND|OR “column” AND|OR “value”];

[ ] = optional

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 18

DELETE FROM Jazzstars WHERE last = ‘Davis’; Just got rid of Miles Davis

DELETE FROM Jazzstars WHERE first = ‘Chet’ AND last = ‘Baker’; Baker is common name

DROP TABLE

Topic Description

DROP TABLE Delete table and all rows in the table

Syntax DROP TABLE “tablename”

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 19

DROP TABLE Jazzstars Table now gone

Table Joins

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 20

One-Table Database

id last first address city state item purchased price paid

1111 Able Adam 123 Main Maple MA X-1000 $45.00

1111 Able Adam 123 Main Mapli MA X-2000 $55.00

1112 Baker James 456 Main Maple MA X-master 1 $55.00

Topic Description

Table Joins Select rows from another table Linking data from tables

Syntax SELECT “list-of-columns” FROM Table1, Table2

WHERE “search_conditions”;

Structure One-Table Database; aka Flat Table, before RDBMS invented

Problem 1: Huge table with lots of redundant data

Problem 2: Redundant data prone to errors (see table below)

Table Joins

Topic Description

Table Joins Select rows from another table Linking data from tables

Syntax SELECT “list-of-columns” FROM Table1, Table2

WHERE “search_conditions”;

Structure RDBMS Database structure can now include 2 tables

1. Customer table for keeping track of customers

2. Purchase table for keeping track of purchases

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 21

Customers Table: “Customers”

id last first address city state zip

1111 Able Adam 123 Main Maple MA 00001

1112 Baker James 456 Main Maple MA 00001

Purchase Table: “Purchases”

id date item price

1111 1/1/2016 X-1000 $45.00

1112 2/1/2016 X-2000 $55.00

Both tables have common ID column

Table Joins

Topic Description

Table Joins Select rows from another table Linking data from tables

Syntax SELECT “list-of-columns” FROM Table1, Table2

WHERE “search_conditions”;

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 22

Example: Select customer’s name and items they purchased:

SELECT Customers.last, Customers.first, Purchases.item FROM Customers, Purchases

WHERE Customers.id = Purchases.id;

Purchase Table: “Purchases”

id date item price

1111 1/1/2016 X-1000 $45.00

1112 2/1/2016 X-2000 $55.00

Customers Table: “Customers”

id last first address city state zip

1111 Able Adam 123 Main Maple MA 00001

1112 Baker James 456 Main Maple MA 00001

SQL Resources: Learning More About SQL: Print Books

Learning SQL

By Alan Beaulieu

Published by O’Reilly Media

SQL in 10 Minutes, Sams Teach Yourself

By Ben Forta

Published by Sams Publishing

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 23

SQL Resources: Learning More About SQL: Online

sqlcourse.com

sqlzoo.net

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 24

SQL Resources: Learning More About SQL: Video

lynda.com/SQL

SQL Essential Training

YouTube.com

SQL basics

Microsoft SQL Server

Oracle RDBMS

Other

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 25

Outline/ Learning Objectives

Topic Description

Introduction Languages to query (get data from) databases

Vendors Top 3 vendors in market

RDBMS Relational Database Management Systems

Commands Litany of various SQL Commands, with examples

Resources Learning more about SQL

© Stephan Sorger 2016; www.StephanSorger.com; SQL: Commands 26