SQL-Exercises-With-Solutions

This repository will be useful to get started and know SQL better. Practice These Exercises.

SQL - Structured Query Language

Used to retrieve Data from Databases.SQL is widely used nowadays because everything is DATA

First Learn the Architectures,So that it will be easy to understand how it works internally:

• Understand Database Architecture
• Learn SQL-Server Architecture
• Then, finally look at the Log Architecture

SQL is classified into 4 types:

• DDL - Data Defenition Language : DDL is abbreviation of Data Definition Language. It is used to create and modify the structure of database objects in database. Examples: CREATE, ALTER, DROP statements

• DML - Data Manipulation Language : DML is abbreviation of Data Manipulation Language. It is used to retrieve, store, modify, delete, insert and update data in database. Examples: SELECT, UPDATE, INSERT statements

• DCL - Data Control Language : DCL is abbreviation of Data Control Language. It is used to create roles, permissions, and referential integrity as well it is used to control access to database by securing it. Examples: GRANT, REVOKE statements

• TCL - Transaction Control Language : TCL is abbreviation of Transactional Control Language. It is used to manage different transactions occurring within a database. Examples: COMMIT, ROLLBACK statements

Know these Concepts

Database:

• A database is a collection of information that is organized so that it can be easily accessed, managed and updated.
• Data is organized into rows, columns and tables, and it is indexed to make it easier to find relevant information.
• Data gets updated, expanded and deleted as new information is added.
• Databases process workloads to create and update themselves, querying the data they contain and running applications against it.

Datamart:

• A data mart is a structure / access pattern specific to data warehouse environments, used to retrieve client-facing data.
• The data mart is a subset of the data warehouse and is usually oriented to a specific business line or team.

Data Warehouse / Enterprise Data Warehouse:

• A large store of data accumulated from a wide range of sources within a company and used to guide management decisions.

Before writing a Querry,Follow these steps

• Analyse the Database and its Available tables
• Select the Tables needed to write our querry
• Identify the JOIN Condition and JOIN type between the tables
• Find the Heirarchy of the table Order
• Define the Condition Statement (eg: WHERE empid = 2)
• Select the Columns from Different Tables
• Define Aggregation if needed
• Data Transformation
• Identify ORDER BY if needed

Tutorial:

• SQL Tutorial

Know the Data types and different Functions used in SQL:

• Data Types: Follow this Link
• Functions: Follow this Link

Let's start Working on Exercises:

Requirements:

Install MS-SQL Server to work on Exercises. To install, Follow this video, he explains clearly.

After Installation, You need Databases to Practice SQL

Note: Following Databases are used in these Exercises. You can Download it or create your own Databases and work on it.

• Download Northwind DB

• Download Adventure Works DB

• Create HR DB on your own

• Creating HR Table and insert the values to the table. Queries

Downloading the Exercises:

• To get started, you can start by either downloading a zip file of these assignments by clicking on the Clone or download button. If you have git installed on your system, you can clone this repository using :

git clone https://github.com/engineeringwitharavind/SQL-Exercises-With-Solutions.git

Each folder contains two files:

A PNG file .png contains Questions for all the Exercises Seperately. A SQL file .sql contains solutions done by me. You can correct me if i am wrong and modify it as needed.

Further Learning:

After Completing these Exercises Try to solve SQL Exercises on

• Mode Analytics

• HackerRank