SQL commands
There are three groups of commands in SQL:
1. Data Definition
2. Data Manipulation and
3. Transaction Control
Characteristics of SQL commands
Here you can see that SQL commands follow a number of basic rules:
• SQL keywords are not normally case sensitive, though this in this tutorial all commands (SELECT, UPDATE etc) are upper-cased.
• Variable and parameter names are displayed here as lower-case.
• New-line characters are ignored in SQL, so a command may be all on one line or broken up across a number of lines for the sake of clarity.
• Many DBMS systems expect to have SQL commands terminated with a semi-colon character.