Gain insights into SQL by exploring database creation, data manipulation, and advanced queries. Learn about practical applications and practice for SQL interviews to build confidence and readiness.

sql.tar.gz

The ability to work SQL is becoming an increasingly in-demand skill, both for software developers and people in less technical roles. If you’re interested in learning SQL and have no prior experience with it, then this course will be your light in a dark tunnel.

You’ll start by covering the basics of SQL such as how to create a database, how to insert, query, and update data. You’ll also learn fundamental concepts that developers and data scientists use everyday such as multi-table operations, nested queries, and how to set up views. 

Throughout, you’ll get to execute SQL queries in your browser and see results in real-time - you won’t need to worry about set-up.

At the end of this course, you’ll also get some hands-on practice with common SQL interview questions, so when the time comes, you’ll be ready and confident to answer any question that comes your way. Let’s get started!

An Introductory Guide to SQL

## EXPLAIN

In this lesson, we'll make a brief introduction to the __EXPLAIN__ statement. The __EXPLAIN__ statement is sort of a dry-run of your query or the blueprint/plan of how the server plans to execute your query. Generally, when complicated queries exhibit performance degradation, we can use the __EXPLAIN__ statement to seek and identify bottlenecks. This lesson is not  a comprehensive treatment of query optimization, rather just a light and general introduction to a vast subject.

Note that __EXPLAIN__ and __DESCRIBE__ are synonyms, however, as a convention __EXPLAIN__ is used with queries whereas __DESCRIBE__ is with structures.


### Syntax
> EXPLAIN **\<SQL Statement\>**;


>Connect to the terminal below by clicking in the widget. Once connected, the command line prompt will show up. Enter or copy and paste the command **./DataJek/Lessons/40lesson.sh** and wait for the MySQL prompt to start-up.

# EXPLAIN

In this lesson, we'll make a brief introduction to the __EXPLAIN__ statement. The __EXPLAIN__ statement is sort of a dry-run of your query or the blueprint/plan of how the server plans to execute your query. Generally, when complicated queries exhibit performance degradation, we can use the __EXPLAIN__ statement to seek and identify bottlenecks. This lesson is not  a comprehensive treatment of query optimization, rather just a light and general introduction to a vast subject.

Note that __EXPLAIN__ and __DESCRIBE__ are synonyms, however, as a convention __EXPLAIN__ is used with queries whereas __DESCRIBE__ is with structures.


## Syntax
> EXPLAIN **\<SQL Statement\>**;


>Connect to the terminal below by clicking in the widget. Once connected, the command line prompt will show up. Enter or copy and paste the command **./DataJek/Lessons/40lesson.sh** and wait for the MySQL prompt to start-up.

This lesson demonstrates the usage of the EXPLAIN statement.

Introduction

Basic SQL

Joins

Nested Queries

Multi Table Operations

Views

Stored Procedures

Triggers

Miscellaneous

Practice & Prep

Epilogue

EXPLAIN

EXPLAIN

Syntax