SQL Tutorial

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Introduction to SQL

What is SQL

  • SQL stands for Structured Query Language and is a standard term for such purposes
  • SQL lets you access and manipulate databases (read and modify)
  • SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987
  • SQL is generally a very plain and self-explanatory English expression or statement

With SQL, one can

  • Read data from a database (SELECT)
  • Insert new data or rows in a database (INSERT)
  • Update/modify existing rows in a database (UPDATE)
  • Delete rows from a database (DELETE)
  • Create new databases
  • Create new tables in database
  • Create view, procedures and other types of objects in a database
  • Change the structure of tables/indexes/other objects (ALTER)
  • Set permissions on tables/procedures/views and other objects

Syntax of a basic SELECT SQL statement:

SELECT field1, field2,...fieldN
[FROM table_name1, table_name2...]
[WHERE Clause]

SQL statements are run against a database and few or all columns are selected from a table stored in database files.
We will study more about database and database management systems in this series.