SQL in 30 DAYS

OVERVIEW

• Use this repository to practice sql queries.
• This repository contains three data analysis projects using SQL.
• Use those projects to learn querying.
• Dont depend entirely on this repository to learn sql.
• There is a lot of free materials available. Google it, find them and learn the concepts from there and use this repo to practice and to view some projects based on sql queries.
• Material that i found useful while learning was from W3schools.

CONTENTS

DAY 1-7

• We will go over the basics of SQL. Like SELECT, INSERT and some functions.
• We will also do three projects on day 4, day 5 and day 6.
• These projects will help you get your hands dirty and make you familiar with SQL queries.

DAY	CONTENTS
DAY 1	create, insert, select, and or not operators, order by
DAY 2	functions sum,avg and count
DAY 3	inner join, left join, right join and outer join
DAY 4-5	Covid-19 data analysis and data visualization
DAY 6	IPL data analysis project
DAY 7	Sales insights project

DAY 8-14

• We will write queries using the employees database.
• Previously we only worked with databases with a single table. Now we will work with multiple tables.
• The database that is used from day 8-14 is taken from here.
• Follow the instructions in that github repository to install the database in your localhost.
• If you have any problems installing the database there are many youtube videos available on how to install it. Refer and do it.

OVERVIEW OF EMPLOYEES DATABASE

• This database is widely used to practice SQL queries.
• This database has six tables employees, dept_manager, department, dept_emp, salaries, titles.
• The schema of the database is shown below.
• 

DAY	CONTENTS
DAY 8	Employees table
DAY 9	titles and salaries tables
DAY 10	department, dept_manager, dept_emp tables
DAY 11	Using employees, salaries, titles tables together
DAY 12	Using department, dept_manager tables together
DAY 13-14	Using all 6 tables together

DAY 15-20

Hackerrank SQL

We have gotten a good understanding of how to write queries. Now lets practice more and more queries using Hackerrank SQL section.

Problem name(code)	Problem Link	Problem Solution
Revising the Select Query I	Link	solution
Revising the Select Query II	Link	solution
Select All	Link	solution
Select By ID	Link	solution
Japanese Cities' Attributes	Link	solution
Japanese Cities' Names	Link	solution
Weather Observation Station 1	Link	solution
Weather Observation Station 3	Link	solution
Weather Observation Station 4	Link	solution
Weather Observation Station 5	Link	solution
Weather Observation Station 6	Link	solution
Weather Observation Station 7	Link	solution
Weather Observation Station 8	Link	solution
Weather Observation Station 9	Link	solution
Weather Observation Station 10	Link	solution
Weather Observation Station 11	Link	solution
Weather Observation Station 12	Link	solution
Higher Than 75 Marks	Link	solution
Employee Names	Link	solution
Employee Salaries	Link	solution
Weather Observation Station 13	Link	solution
Weather Observation Station 14	Link	solution
Weather Observation Station 15	Link	solution
Weather Observation Station 17	Link	solution
Weather Observation Station 18	Link	solution
Weather Observation Station 20	Link	solution
Revising Aggregations - Averages	link	solution
Average Population	link	solution
Population Density Difference	link	solution
The Blunder	link	solution
Top Earners	link	solution
Type of Triangle	link	solution
Population Census	link	solution
African Cities	link	solution
Placements	link	solution
New Companies	link	solution