Important Concepts in SQL

In this section you will find Important concepts related to SQL.
The concepts are divided in three parts:

Standard SQL - Important Concepts

There are four main categories which one usually divide Standard SQL into, which are:
- Data Query Language (DQL)
  - Perform queries towards the underlying data, which includes a SELECT clause
  - Examples: SELECT Country FROM Geography
- Data Definition Language (DDL)
  - Perform Operations on a specific database
  - Examples: CREATE, DROP, ALTER, TRUNCATE
- Data Manipulation Language (DML)
  - Perform Manipulation of data in a database
  - Examples: INSERT, UPDATE, DELETE
- Data Control Language (DCL)
  - Deals with rights and permission to specific data
  - Examples: GRANT, REVOKE
- RDBMS stands for Relational DataBase Management System
- DBMS stands for DataBase Management System
- DBMS is the overall term
- RDBMS is a subset of a DBMS which stores data in a specific way with different rules set on the relation between the different Relations in the DBMS.
Some of the most common clauses in the SELECT statement are:
- FROM
- JOIN
- WHERE
- GROUP BY
- ORDER BY