SQL?
SQL  stands for 
Structured Query Language. SQL is used to communicate with a database. 
According to ANSI (American National Standards Institute), it is the 
standard language for relational database management systems. SQL 
statements are used to perform tasks such as update data on a database, 
or retrieve data from a database. Some common relational database 
management systems that use SQL are: Oracle, Sybase, Microsoft SQL 
Server, Access, Ingres, etc. Although most database systems use SQL, 
most of them also have their own additional proprietary extensions that 
are usually only used on their system. However, the standard SQL 
commands such as "Select", "Insert", "Update", "Delete", "Create", and 
"Drop" can be used to accomplish almost everything that one needs to do 
with a database. This tutorial will provide you with the instruction on 
the basics of each of these commands as well as allow you to put them to
 practice using the SQL Interpreter.
 SQL queries
The SQL queries are the most common and essential SQL operations. Via an
 SQL query, one can search the database for the information needed. SQL 
queries are executed with the “SELECT” statement. An SQL query can be 
more specific, with the help of several clauses:
- FROM - it indicates the table where the search will be made.
 
- WHERE - it's used to define the rows, in which the search will be 
carried. All rows, for which the WHERE clause is not true, will be 
excluded.
 
- ORDER BY - this is the only way to sort the results in SQL. Otherwise, they will be returned in a random order.  
 
 Simple Exampl Of SQL  
Sql Example