SQL Database Language

  1. Basic Data Retrieval with SELECT
    1. SELECT Statement Fundamentals
      1. Basic Syntax Structure
        1. Execution Order Concepts
          1. Query Processing Flow
          2. Selecting Columns
            1. All Columns Selection
              1. Asterisk Wildcard
                1. Performance Considerations
                  1. Best Practices
                  2. Specific Column Selection
                    1. Column Name Specification
                      1. Column Order Control
                        1. Non-Existent Column Handling
                        2. Calculated Columns
                          1. Arithmetic Expressions
                            1. String Concatenation
                              1. Function Applications
                              2. Column Aliases
                                1. AS Keyword Usage
                                  1. Alias Naming Rules
                                    1. Quoted Aliases
                                      1. Alias Scope
                                    2. DISTINCT Keyword
                                      1. Duplicate Elimination
                                        1. Performance Impact
                                          1. Multiple Column DISTINCT
                                            1. DISTINCT vs GROUP BY
                                            2. FROM Clause Essentials
                                              1. Table Specification
                                                1. Schema Qualification
                                                  1. Table Aliases
                                                    1. Alias Definition
                                                      1. Alias Usage Benefits
                                                        1. Correlation Names
                                                      2. WHERE Clause Filtering
                                                        1. Basic Filtering Concepts
                                                          1. Filter Condition Structure
                                                            1. Comparison Operators
                                                              1. Equal To
                                                                1. Not Equal To
                                                                  1. Greater Than
                                                                    1. Less Than
                                                                      1. Greater Than or Equal
                                                                        1. Less Than or Equal
                                                                        2. Logical Operators
                                                                          1. AND Operator
                                                                            1. Multiple Conditions
                                                                              1. Operator Precedence
                                                                              2. OR Operator
                                                                                1. Alternative Conditions
                                                                                  1. Parentheses Usage
                                                                                  2. NOT Operator
                                                                                    1. Negation Logic
                                                                                      1. De Morgan's Laws
                                                                                    2. Range and Set Operators
                                                                                      1. BETWEEN Operator
                                                                                        1. Inclusive Range Testing
                                                                                          1. Date Range Queries
                                                                                            1. Numeric Range Queries
                                                                                            2. IN Operator
                                                                                              1. Value List Testing
                                                                                                1. Subquery Integration
                                                                                                  1. Performance Characteristics
                                                                                                  2. NOT IN Considerations
                                                                                                    1. NULL Value Handling
                                                                                                      1. Unexpected Results
                                                                                                    2. Pattern Matching
                                                                                                      1. LIKE Operator
                                                                                                        1. Wildcard Characters
                                                                                                          1. Percent Sign Usage
                                                                                                            1. Underscore Usage
                                                                                                              1. Escape Characters
                                                                                                              2. Case Sensitivity in Patterns
                                                                                                                1. Regular Expressions
                                                                                                                2. NULL Value Handling
                                                                                                                  1. IS NULL Testing
                                                                                                                    1. IS NOT NULL Testing
                                                                                                                      1. NULL Comparison Pitfalls
                                                                                                                        1. Three-Valued Logic
                                                                                                                      2. Sorting Results
                                                                                                                        1. ORDER BY Clause
                                                                                                                          1. Basic Sorting Syntax
                                                                                                                            1. Default Sort Order
                                                                                                                            2. Sort Directions
                                                                                                                              1. Ascending Order
                                                                                                                                1. Descending Order
                                                                                                                                  1. Mixed Sort Orders
                                                                                                                                  2. Multi-Column Sorting
                                                                                                                                    1. Sort Priority
                                                                                                                                      1. Secondary Sort Criteria
                                                                                                                                      2. Sorting by Expressions
                                                                                                                                        1. Calculated Field Sorting
                                                                                                                                          1. Function-Based Sorting
                                                                                                                                          2. NULL Value Sorting
                                                                                                                                            1. NULLS FIRST
                                                                                                                                              1. NULLS LAST
                                                                                                                                                1. Default NULL Handling
                                                                                                                                              2. Limiting Result Sets
                                                                                                                                                1. Row Limitation Concepts
                                                                                                                                                  1. LIMIT Clause
                                                                                                                                                    1. MySQL Syntax
                                                                                                                                                      1. PostgreSQL Syntax
                                                                                                                                                        1. Row Count Specification
                                                                                                                                                        2. OFFSET Clause
                                                                                                                                                          1. Skip Row Functionality
                                                                                                                                                            1. Pagination Implementation
                                                                                                                                                            2. TOP Clause
                                                                                                                                                              1. SQL Server Syntax
                                                                                                                                                                1. Percentage Options
                                                                                                                                                                2. FETCH Clause
                                                                                                                                                                  1. Standard SQL Syntax
                                                                                                                                                                    1. FIRST and NEXT Options
                                                                                                                                                                    2. Performance Considerations
                                                                                                                                                                      1. Index Usage
                                                                                                                                                                        1. Large Result Set Handling