SQL ORDER BY clause tutorial: sort results ascending or descending, sort by several columns, by expressions and aliases, handle NULLs, and see each result.
Tag: SQL for Beginners
SQL AND, OR, NOT Operators: Combine Multiple Conditions
SQL AND, OR and NOT operators let you combine several WHERE conditions. Learn precedence, parentheses, worked examples with results and the mistakes to avoid.
SQL WHERE Clause: Filter Rows with Conditions (Examples)
SQL WHERE clause tutorial: filter rows with =, <>, >, <, BETWEEN, LIKE and IN, quote text correctly, use WHERE in UPDATE and DELETE, plus common mistakes.
SQL SELECT DISTINCT: Remove Duplicate Rows from Results
SQL SELECT DISTINCT returns only unique values. Learn the syntax, DISTINCT on one or several columns, COUNT(DISTINCT), NULL handling and common mistakes.
SQL SELECT Statement: Retrieve Data from a Table (Examples)
SQL SELECT statement tutorial: select all columns or specific columns, use expressions and calculated columns, and see the exact output of each query.
SQL Syntax: Rules, Statement Structure and Clause Order
SQL syntax explained: how statements, clauses and keywords fit together, the clause order rule, case sensitivity, semicolons, quotes, comments and errors.
SQL Quiz: 75 Practice Questions with Instant Answers (Free)
Free SQL quiz with 75 questions on SELECT, WHERE, joins, GROUP BY, subqueries and window functions. 20 random questions per attempt, with instant feedback.
SQL Introduction: What Is SQL and How Databases Use It
SQL introduction for beginners: what SQL is, what a relational database is, the main SQL commands, which databases use it, and how to run your first query.