Informix Guide to SQL: Tutorial Composing SELECT Statements

In This Chapter

Introducing the SELECT Statement

Some Basic Concepts

Privileges

Relational Operations

Selection and Projection

Joining

The Forms of SELECT

Special Data Types

Single-Table SELECT Statements

Selecting All Columns and Rows

Using the Asterisk Symbol (*)

Reordering the Columns

Sorting the Rows

Selecting Specific Columns

Selecting Substrings

ORDER BY and Non-English Data

Using the WHERE Clause

Creating a Comparison Condition

Including Rows

Excluding Rows

Specifying A Range of Rows

Excluding a Range of Rows

Using a WHERE Clause to Find a Subset of Values

Identifying Null Values

Forming Compound Conditions

Using Exact-Text Comparisons

Using Variable-Text Searches

Using a Single-Character Wildcard

MATCHES and Non-English Data

Protecting Special Characters

Using Subscripting in a WHERE Clause

Using a FIRST Clause to Select Specific Rows

FIRST Clause Without an ORDER BY Clause

FIRST Clause with an ORDER BY Clause

FIRST Clause in a Union Query

Expressions and Derived Values

Arithmetic Expressions

CASE Expressions

Sorting on Derived Columns

Using Rowid Values In SELECT Statements

Using Rowid Values with the USER Function

Using Rowid Values with the DBSERVERNAME Function

Multiple-Table SELECT Statements

Creating a Cartesian Product

Creating a Join

Equi-Join

Natural Join

Multiple-Table Join

Some Query Shortcuts

Using Aliases

The INTO TEMP Clause

Selecting Tables from a Database Other Than the Current Database

Summary