SQL Database Language

3.

Basic Data Retrieval with SELECT

3.1.

SELECT Statement Fundamentals

3.1.1.

Basic Syntax Structure

3.1.2.

Execution Order Concepts

3.1.3.

Query Processing Flow

3.2.

Selecting Columns

3.2.1.

All Columns Selection

3.2.1.1.

Asterisk Wildcard

3.2.1.2.

Performance Considerations

3.2.1.3.

3.2.2.

Specific Column Selection

3.2.2.1.

Column Name Specification

3.2.2.2.

Column Order Control

3.2.2.3.

Non-Existent Column Handling

3.2.3.

Calculated Columns

3.2.3.1.

Arithmetic Expressions

3.2.3.2.

String Concatenation

3.2.3.3.

Function Applications

3.2.4.

3.2.4.1.

AS Keyword Usage

3.2.4.2.

Alias Naming Rules

3.2.4.3.

3.2.4.4.

3.3.

DISTINCT Keyword

3.3.1.

Duplicate Elimination

3.3.2.

Performance Impact

3.3.3.

Multiple Column DISTINCT

3.3.4.

DISTINCT vs GROUP BY

3.4.

FROM Clause Essentials

3.4.1.

Table Specification

3.4.2.

Schema Qualification

3.4.3.

3.4.3.1.

Alias Definition

3.4.3.2.

Alias Usage Benefits

3.4.3.3.

Correlation Names

3.5.

WHERE Clause Filtering

3.5.1.

Basic Filtering Concepts

3.5.2.

Filter Condition Structure

3.5.3.

Comparison Operators

3.5.3.1.

3.5.3.2.

3.5.3.3.

3.5.3.4.

3.5.3.5.

Greater Than or Equal

3.5.3.6.

Less Than or Equal

3.5.4.

Logical Operators

3.5.4.1.

3.5.4.1.1.

Multiple Conditions

3.5.4.1.2.

Operator Precedence

3.5.4.2.

3.5.4.2.1.

Alternative Conditions

3.5.4.2.2.

Parentheses Usage

3.5.4.3.

3.5.4.3.1.

3.5.4.3.2.

De Morgan's Laws

3.5.5.

Range and Set Operators

3.5.5.1.

BETWEEN Operator

3.5.5.1.1.

Inclusive Range Testing

3.5.5.1.2.

Date Range Queries

3.5.5.1.3.

Numeric Range Queries

3.5.5.2.

3.5.5.2.1.

Value List Testing

3.5.5.2.2.

Subquery Integration

3.5.5.2.3.

Performance Characteristics

3.5.5.3.

NOT IN Considerations

3.5.5.3.1.

NULL Value Handling

3.5.5.3.2.

Unexpected Results

3.5.6.

Pattern Matching

3.5.6.1.

3.5.6.1.1.

Wildcard Characters

3.5.6.1.2.

Percent Sign Usage

3.5.6.1.3.

Underscore Usage

3.5.6.1.4.

Escape Characters

3.5.6.2.

Case Sensitivity in Patterns

3.5.6.3.

Regular Expressions

3.5.7.

NULL Value Handling

3.5.7.1.

IS NULL Testing

3.5.7.2.

IS NOT NULL Testing

3.5.7.3.

NULL Comparison Pitfalls

3.5.7.4.

Three-Valued Logic

3.6.

Sorting Results

3.6.1.

ORDER BY Clause

3.6.1.1.

Basic Sorting Syntax

3.6.1.2.

Default Sort Order

3.6.2.

Sort Directions

3.6.2.1.

Ascending Order

3.6.2.2.

Descending Order

3.6.2.3.

Mixed Sort Orders

3.6.3.

Multi-Column Sorting

3.6.3.1.

3.6.3.2.

Secondary Sort Criteria

3.6.4.

Sorting by Expressions

3.6.4.1.

Calculated Field Sorting

3.6.4.2.

Function-Based Sorting

3.6.5.

NULL Value Sorting

3.6.5.1.

3.6.5.2.

3.6.5.3.

Default NULL Handling

3.7.

Limiting Result Sets

3.7.1.

Row Limitation Concepts

3.7.2.

3.7.2.1.

3.7.2.2.

PostgreSQL Syntax

3.7.2.3.

Row Count Specification

3.7.3.

3.7.3.1.

Skip Row Functionality

3.7.3.2.

Pagination Implementation

3.7.4.

3.7.4.1.

SQL Server Syntax

3.7.4.2.

Percentage Options

3.7.5.

3.7.5.1.

Standard SQL Syntax

3.7.5.2.

FIRST and NEXT Options

3.7.6.

Performance Considerations

3.7.6.1.

3.7.6.2.

Large Result Set Handling

Previous

2. SQL Fundamentals and Syntax

Go to top

Next

4. Data Manipulation Operations