SQL

SQL

1. Some of The Most Important SQL Commands

   • SELECT - extracts data from a database
   • UPDATE - updates data in a database
   • DELETE - deletes data from a database
   • INSERT INTO - inserts new data into a database
   • CREATE DATABASE - creates a new database
   • ALTER DATABASE - modifies a database
   • CREATE TABLE - creates a new table
   • ALTER TABLE - modifies a table
   • DROP TABLE - deletes a table
   • CREATE INDEX - creates an index (search key)
   • DROP INDEX - deletes an index
   • WHERE - extracts only those records that fulfill a specified criterion
     • SELECT column_name,column_name FROM table_name WHERE column_name operator value;

2. Operator

   • BETWEEN - Between an inclusive range
   • LIKE - Search for a pattern
   • IN - To specify multiple possible values for a column
   • <> or != - means not equal