SQL

What is SQL?

–When a user wants to get some information from a database file, he can issue a query

–A query is a user–request to retrieve data or information with a certain condition.

–SQL is a query language that allows user to specify the conditions. (instead of algorithms)

Concept of SQL

–The user specifies a certain condition.

–The program will go through all the records in the

  database file and select those records that satisfy the

  condition.(searching).

–Statistical information of the data.

–The result of the query will then be stored in form of a

   table.