Basic Notes

1 min readApr 30, 2020


SQL subcategories

  • DDL: Data definition language: create the table, alter and drop.
  • DCL: Data Control Language: grant, revoke
  • DML: Data Management Language. insert, update, delete, get

Recommended style: snake case, lowercase

Second most popular: camel case

select * from table_name

This will return all the entries in the given table_name.


SQL is a structured query language to manage a relational database.

MYSQL is a relational database management system to store the data retreive modify using sql. MYSQL is a platform, software, providing an integrated tool environment designed to model databases. Also provides database drivers in .net .php, c++, Python ,Java to build a database applications.

Database Drivers: We pass a query string to connect with a language of the front end.

Primary Key: We identify the table using the primary key and the foreign key.

Has aliases to shorten names that are too long..

Has aggregate functions (min (), max(), count(), sum(), avg())

SQL syntax

-- This is how to make a commentselect * from customers
-- * grabs all the columns

You can comment out multiple lines of SQL in multiple ides with control k.

To grab a specific column in the table we can use the following syntax.

select name_of_column from table_name