This post talks about SQL: SQL stands for Structured Query Language, the name itself states that this language is used to query the existing database with certain operations and with SQL we can create tables so on. SQL commands are categorized into 4 categories. They are 1) DDL (Data Definition Language) : It is used to define the database structure and schema. Commands used in the DDL are - CREATE (this command is used to create new table, table from existing table, index, function, views, store procedure and triggers) Syntax: - ALTER (this command is used to change the structure of existing database) - DROP (this command is used to delete an object from database) - TRUNCATE (this command is used to remove all records from a table, including all spaces allocated for the records are removed) - COMMENT (this command is used to add comments to the data dictionary) - RENAME (this command is used to rename an object existing in the database) 2) DML (Data Manipulation Language) : These are