Introduction
SQL stands for Structured Query Language. SQL is composed of three subsets which are Data Definition Language (DDL), Data Manipulation Language (DML), and Data Control Language (DCL). SQL is the conventional language used to interact with a relational database through activities such as data insertion, data update, data deletion, and data retrieval. SQL makes it simpler for a programmer to interact with a relational database by abstracting most of the logic underlying how data is manipulated hence allowing the programmer to focus on their data.
SQL supports comments like most programming languages. Comments make an application easier to understand and maintain. SQL comments are formatted statements that do not interfere with the execution of SQL statements. SQL supports both single line comments and block comments that span multiple lines. A block SQL comment must start with a forward slash followed by an asterisk (/*) and end with an asterisk followed by a forward slash (*/). A single line SQL comment can either be placed within /* comment */ or start with two successive hyphens (--).