SQL

Welcome again everyone, 

Today we are gonna touch the upper surface of usage of SQL in data analysis. 

SQL Stands for Structured Queries Language. It is language which we use to talk with database. Each line of code is called query. 

It is like talking to someone in his/her regional language and asking for some work to done. 

We request database to do a work for us in database language (SQL) and take the outcome. 

Cool so this was the concept of SQL. 

Now how we use it. 

It has very less syntex and spaces don't matter in SQL

Let's see a small query

SELECT * 

FROM database.dataset.table

WHERE 

Attribute = "varchar"

In this query we are using * for selecting all the columns.

In FROM we selected table

WHERE give a condition to see table.

There are a lot of different functions in SQL, following are few common functions-

- SELECT

-WHERE

-SELECT

-ORDER BY

-CAST

-DISTINCT 

-COUNT 

-LIMIT

There is also concept of subqueries, which means queries under queries. We use it to make complex queries and find insights from data.

Most common SQL database and RDBMS are given below-

MySQL

MS SQL server

Oracle SQL 

postgre SQL

Bigquery etc.