The Language of SQL- P2 pps

About the Author
Larry Rockoff has been involved with SQL and Business Intelligence (BI) de-
velopment for many years. His main area of expertise is with data warehouse
systems and reporting tools. He recently developed a suite of BI tools for ASA P
Software, a subsidiary of Dell Inc. He holds an MBA from the University of
Chicago, with a specialization in Management Science.
For more information on his current activities or to contact the author, please
visit LarryRockoff.com.
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Contents
Introduction . . xii
Chapter 1 Relational Databases and SQL 1
Language and Logic 1
SQL Defined. . . 3
Microsoft SQL Server, Oracle, and MySQL 3
Other Databases 5
Relational Databases 6
Primary and Foreign Keys . . 7
Datatypes 8
NULL Values. . . 10
The Significance of SQL 10
Looking Ahead 11
Chapter 2 Basic Data Retrieval 13
A Simple SELECT 13
Syntax Notes . . 15
Specifying Columns 16
Column Names with Embedded Spaces . . 17
Looking Ahead 18
Chapter 3 Calculations and Aliases 19
Calculated Fields 19
Literal Values . . 20

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Arithmetic Calculations 22
Concatenating Fields 23
Column Aliases . 24
Table Aliases . . . 26
Looking Ahead . 27
Chapter 4 Using Functions 29
The Function of Functions . . . 29
Character Functions 30
Composite Functions 36
Date/Time Functions 37
Numeric Functions 40
Conversion Functions 41
Looking Ahead . 44
Chapter 5 Sorting Data 47
Adding a Sort . . 47
Sorting in Ascending Order. . 48
Sorting in Descending Order . 49
Sorting by Multiple Columns. 50
Sorting by a Calculated Field. 51
More on Sort Sequences 52
Looking Ahead . 55
Chapter 6 Column-Based Logic . 57
IF-THEN-ELSE Logic 57
The Simple Format 58
The Searched Format 60
Looking Ahead . 62
Chapter 7 Row-Based Logic 63
Applying Selection Criteria . . 63
WHERE Clause Operators 65

Limiting Rows . . 66
Limiting Rows with a Sort . . . 68
Looking Ahead . 70
Chapter 8 Boolean Logic 71
Complex Logical Conditions . 71
Contents vii
The AND Operator 72
The OR Operator 73
Using Parentheses 73
Multiple Sets of Parentheses 75
The NOT Operator 76
The BETWEEN Operator 79
The IN Operator 80
Boolean Logic and NULL Values 82
Looking Ahead 84
Chapter 9 Inexact Matches . . . 85
Pattern Matching 85
Wildcards 88
Matching by Sound 91
Looking Ahead 93
Chapter 10 Summarizing Data . 95
Eliminating Duplicates 95
Aggregate Functions 97
The COUNT Function 99
Grouping Data 101
Multiple Columns and Sorting 103
Selection Criteria on Aggregates 105
Looking Ahead 107
Chapter 11 Combining Tables with an Inner Join 109
Joining Two Tables 110

The Inner Join . 112
Table Order in Inner Joins . . 114
Alternate Specification of Inner Joins . . . 114
Table Aliases Revisited 115
Looking Ahead 116
Chapter 12 Combining Tables with an Outer Join 119
The Outer Join. 119
Left Joins 122
Testing for NULL Values 124
Right Joins 125
Table Order in Outer Joins. . 125
Contentsviii
Full Joins 126
Looking Ahead . 128
Chapter 13 Self Joins and Views . 131
Self Joins 131
Creating Views . 134
Referencing Views 136
Benefits of Views 137
Modifying and Deleting Views 138
Looking Ahead . 139
Chapter 14 Subqueries 141
Types of Subqueries 141
Using a Subquery as a Data Source 142
Using a Subquery in Selection Criteria 145
Correlated Subqueries 147
The EXISTS Operator 149
Using a Subquery as a Calculated Column. . 150
Looking Ahead . 151
Chapter 15 Set Logic 153

Using the UNION Operator . . 154
Distinct and Non-Distinct Unions 157
Intersecting Queries 158
Looking Ahead . 160
Chapter 16 Stored Procedures and Parameters . . 163
Creating Stored Procedures. . 164
Parameters in Stored Procedures 166
Executing Stored Procedures. 168
Modifying and Deleting Stored Procedures 169
Functions Revisited 170
Looking Ahead . 171
Chapter 17 Modifying Data 173
Modification Strategies 173
Inserting Data . . 174
Deleting Data . . 178
Updating Data. . 180
Contents ix