SQL (pronounced “sequel” or “S-Q-L”) stands for Structured Query Language. It is a standard computer language that is used to communicate with databases. In other words, it lets you talk to the database to extract data or make changes. Looking at recent job postings, you’ll see that SQL skills are increasingly in demand. This is because data is becoming more and more critical in business, and SQL is beneficial for everyone to know, not just data professionals.
Two main groups use SQL for different purposes. The first is developers using SQL to build or interact with the database. Most, if not all, of the apps on your computer or the web apps you use daily are powered by a database. When you access an app or input your data, SQL codes are executed in the backend to read or write data to a database.
- Insert data into a database: If you are developing an app, you will need to insert data into the database. For example, when new users sign up for your app, their information needs to be added to the database.
- Update data in a database: This is another common task for developers. For example, if a user changes their address, you must update the database accordingly.
- Delete data from a database: You may also need to delete data from a database. For example, if a user deletes their account, you must remove their data from the database.
The second user group is business people who retrieve data from databases for business analysis. These will be the most popular use cases that business people will perform. Knowing how to extract data from a database and perform simple data analysis will be very useful in your career. Examples of activities include:
- Retrieve data from a database: This is the most basic thing you can do with SQL. You can use various filters to specify exactly what data you want to retrieve. For example, you could retrieve all data about customers in California who have purchased within the last month.
- Perform data analysis: SQL is also commonly used for data analysis. For example, you could use SQL to calculate the average purchase amount for all customers in California.
Why is knowing SQL beneficial?
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Learning SQL will allow you to be more data-driven in your decision-making as a business person. In today’s business world, data is becoming increasingly important. Instead of waiting for someone else to provide you with data, you can access the data yourself and get the answers you need promptly.
Working with the data yourself will also make you more data-literate. This means that you will be able to understand data better when it is presented to you, and you will also be able to communicate your data needs to others more effectively. Those who can effectively analyze data will have a distinct advantage over those who cannot.
SQL is also a valuable skill to have on your resume. As mentioned before, SQL skills are increasingly in demand, and knowing SQL will make you more marketable to potential employers.
I already know Excel. Why bother learning?
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Excel is an excellent tool for small data sets but quickly becomes cumbersome when data size grows. Each Excel file has a limit on the number of rows it can contain (about 1 million rows). When you have data beyond this limit, you need to split your data into multiple files or use another tool. Your organization’s data is also typically not stored in your computer. Therefore, it can be time-consuming and cumbersome to gather data from different data sources into your computer for analysis. On the other hand, SQL is designed to work with large data sets and can be 10–100 times faster than Excel.
Besides the data size limitation, another issue with Excel is that it is designed for single-user usage. In other words, it assumes that only one person is using the data simultaneously. The data is stored locally on your computer, and if two people are working on the same data set, they need to merge their changes together manually. This can lead to errors and data inconsistencies. In contrast, SQL databases are designed for concurrent multi-user usage. Users can query data stored centrally without affecting each other’s work.
Another problem with Excel is that data in different files can’t be easily merged. If you have data in two different Excel files, you must manually copy and paste data from one file to another. This is not only time-consuming but also error-prone. Worst, if you make a mistake in your analysis, it can be tough to track down the error since data is scattered across different steps. Even if you track down the error, you still need to perform all of the VLOOKUP and copy & paste again.
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How can I start learning SQL?
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If you want to learn SQL, there are two main steps: learning the language and using the language. With the learning part, there are tons of resources available for you to start learning:
Besides these resources, you can find instruction videos on YouTube, books, and boot camps.
Once you have the technical part down, it is time to start applying what you learnt to answer real-world business problems. And the best way to do that is to find data that you are interested in and start playing around with it. Your organization likely already have a data warehouse or you can look for public dataset. This is an essential step because it allows you to apply the concepts you have learned in a meaningful way. Do this well, and you will find that you are quickly becoming proficient in SQL.
The data you use for this does not need to be big. In fact, it is often easier to start with small and well-structured data. An excellent place to find data sets that are small and well-structured. In the next piece, I will discuss how you can learn SQL by using the language in a business setting.
As businesses become more data-driven, the demand for SQL skills increases. SQL is a versatile skill that can be used by anyone who wants to retrieve and analyze data.
Start learning SQL to give yourself an edge.