Welcome to SQL (SQL 101)

If you want to find a BI Analyst job in New Zealand, you may be not a master of Python, R, etc.

However, SQL knowledge is essential.

Here is a BI Analyst job advertisement on LinkedIn, which is a full-time role.

St John is also an accredited employer.

If you have a skill that is needed by a New Zealand accredited employer and they offer you full-time work when you are abroed, you may be able to get a Talent (Accredited Employer) Work Visa.

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From the job description, we can find SQL knowledge is important.

What is SQL?

Firstly, I want to talk about Database(DB). We all know DB is a kind of software to store a large amount of data, mainly Relational DB.

Structured Query Language(SQL) is always linked with DB. SQL can be used to operate data, such as querying and updating.

The relationship between DB, data and SQL is like: DB is a plate, data is dishes on the plate and SQL is your fork.

Currently, most of the websites and Apps are based on SQL and DB.

There are several popular DB on the world, e.g., SQLite, MySQL, Postgres, Oracle and Microsoft SQL Server.

Among them, MSSQL Server is the most popular in New Zealand.

Luckily, all of them can support SQL although they have different characteristics.

It is like if you have the fork, you can operate dishes on different plates.

A DB is composed of several tables (like tables in Excel) and tables are composed of rows and columns.

We can query and obtain some results from the DB through SQL language.

Maybe some people will be confused about: What is the difference between DB and Excel? Excel has already existed on the world, why SQL is created?

That is because DB = Tables + Relations between tables.

Tables in Excel can’t meet the data operating requirements in companies because of the complex relations between tables.

How to kick-start SQL?

After knowing the terms of SQL and Relational DB, the next step is to set up the environment with SQL Server, which we will talk in the next blog.

If you are interested in or have any problems with Business Intelligence, also feel free to contact me .

Or you can connect with me through my LinkedIn.

Originally published at http://jacquiwu.com on July 24, 2019.

Written by

A current Data Analyst in a subsidiary under Webjet, with experience in applying data science techniques to business.

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