whatisSQLandwheredoesitcome from?

what is SQL and where does it come from?

Structured Query Language (SQL) is a language that provides an interface to relational database systems. The proper pronunciation of SQL, and the preferred pronunciation within Oracle Corp, is "sequel" and not "ess cue ell".
SQL was developed by IBM in the 1970s for use in System R, and is a de facto standard, as well as an ISO and ANSI standard.
In common usage SQL also encompasses DML (Data Manipulation Language), for INSERTs, UPDATEs, DELETEs and DDL (Data Definition Language), used for creating and modifying tables and other database structures.
The development of SQL is governed by standards. A major revision to the SQL standard was completed in 1992, called SQL2. SQL3 support object extensions and are (partially?) implemented in Oracle8 and 9i.
Example SQL statements:

CREATE TABLE table1 (column1 NUMBER, column2 VARCHAR2(30));

INSERT INTO table1 VALUES (1, 'XYZ');

SELECT * FROM table1 WHERE column2 = 'XYZ';