Comprehensive Guide to SQL Syntax, Queries, and Database Operations

This article provides an extensive overview of relational database concepts and SQL syntax, covering basic terminology, clause structures, and the main language categories DDL, DML, TCL, and DCL.

It explains how to write and format SQL statements for creating, altering, and dropping databases and tables, inserting, updating, deleting, and selecting data, as well as using subqueries, joins, unions, grouping, ordering, and aggregate functions.

Additional sections cover functions for text, date/time, and numeric processing, transaction control with SAVEPOINT and COMMIT, user privilege management with GRANT and REVOKE, and advanced features such as stored procedures, cursors, and triggers, each illustrated with SQL code examples.

CREATE DATABASE test;

INSERT INTO user (id, username, password, email) VALUES (1, 'root', 'root', '[email protected]');

SELECT prod_name, prod_price FROM products WHERE vend_id IN ('DLL01', 'BRS01') ORDER BY prod_price DESC;

DELIMITER $$
CREATE PROCEDURE proc_adder(IN a INT, IN b INT, OUT sum INT)
BEGIN
    SET sum = a + b;
END$$
DELIMITER ;