SQL UNION vs UNION ALL
Learn SQL UNION and UNION ALL with examples. Understand the difference, performance impact, and when to use UNION vs UNION ALL.
SQL Joins
Master SQL Joins with real-world examples. Learn INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL OUTER JOIN, CROSS JOIN, and Self Join in one guide.
SQL Subqueries
Learn SQL Subqueries with examples: single-row, multi-row, and correlated subqueries for advanced data retrieval.
SQL HAVING Clause
Learn SQL HAVING clause with examples to filter grouped records after using GROUP BY.
GROUP BY Clause
Learn SQL GROUP BY clause with examples for grouping data by columns and using aggregate functions.
SQL Aggregate Functions – COUNT, SUM, AVG, MIN, MAX
Learn SQL aggregate functions with examples: COUNT, SUM, AVG, MIN, MAX for summarizing data.
SQL Comments
Learn how to use SQL comments to document queries using single-line (–) and multi-line (/* … */) comments with examples.
SQL Aliases
Learn SQL aliases using AS to rename columns or tables for better readability. Step-by-step examples included.
SQL Basic Functions
Learn SQL basic functions like UPPER, LOWER, ROUND, NOW(), and DATE functions. Step-by-step examples for string, number, and date operations.
SQL LIMIT & FETCH FIRST
Learn SQL LIMIT and FETCH FIRST for row limiting. Step-by-step guide with syntax, examples, and practice queries for MySQL, PostgreSQL, and SQL Server.