SQL Guid

SQL-structured query language

SQL is a standard computer language for accessing and processing databases.

Common database management systems: MySQL, SQL Server, Access, Oracle, Sybase, and DB2

For those who want to store and obtain data in a database, the knowledge of SQL is of immeasurable value.

What is SQL?

• SQL refers to structured query language ( S Tructured Q Uery L Anguage)

• SQL gives us the ability to access the database

• SQL is a standard computer language of ANSI.

• SQL executes queries against the database

• SQL can retrieve data from the database

• SQL can insert new records in the database

• SQL can delete records from the database

• SQL is easy to learn.

SQL database table

A database usually contains one or more tables. Each table is identified by a name (such as “customer” or “order”). The table contains records (rows) with data.

The following example is a table named “Persons”:

The above table contains three records (each for a person) and four columns (last name, first name, address, and city).

SQL query program

With SQL, we can query a database and get a result set returned.

The query program looks like this:

SELECT LastName FROM Persons

The result set looks like this:

How to learn SQL?

Visit our complete SQL tutorial