SQL (Structured Query Language) is used to modify and access data or information from a storage area called database. This beginner online training SQL tutorial website teaches you the basics of SQL code and trains you how to write & program SQL queries. I will be sharing my database knowledge on SQL and help you learn programming SQL better.
The concepts discussed in this SQL tutorial can be applied to most of the database systems. The SQL syntax used to explain the tutorial concepts is similar to the one used in Oracle database.
What is SQL? SQL stands for “Structured Query Language” and can be pronounced as “SQL” or “sequel – (Structured English Query Language)”. Defined, SQL is a query language used for accessing and modifying information in one or more data tables and rows of a database.
IBM first developed SQL in the 1970s. Also, it is an ANSI/ISO standard. It has become a Standard Universal Language used by most of the relational database management systems (RDBMS). Some of the RDBMS systems are Oracle, Microsoft SQL Server, Sybase etc.
Most of these have provided their own implementation extensions, thus enhancing their RDBMS system features and making it a powerful tool. These RDBMS systems, all use the popular SQL commands SELECT, UPDATE, DELETE, INSERT, WHERE in a similar format.
SQL database is constructed of a number of tables. In a business, SQL tables would be used to divide and simplify the different areas of the operation: Table for Customers, one for Vendors, Employees and so on.
Each SQL table is made up of a number of columns, referred to as fields and run along the top of the table. SQL columns or fields have their content (object/data/info) defined into character types; such as text, date, numeric, integer, length to name a few.
Each SQL table row, referred to a record, is located in the left column of the table. SQL record row will contain a string of data containing data matching up to each column field across the top. So, in a “Customer table” each “customer record” would consist of one row with data for the customer ID number, customer name, address, phone …email and so on.
Few of the SQL commands used in SQL code programming are: SELECT Statement, UPDATE Statement, INSERT INTO Statement, DELETE Statement, WHERE Clause, ORDER BY Clause, SQL GROUP BY Clause, Subquery Clauses, Joins, Views, GROUP Functions, Indexes etc.
In a simple manner, SQL is a non-procedural, English-like language that processes data in groups of records rather than one record at a time. Few SQL functions are:
Source: SQL Tutorial, Tutorials SQL