The Basics of SQL: Beginner’s Guide on How to Use SQL Database
SQL is an abbreviation for structured query language and it is a well-known method for querying databases. It doesn’t matter if you want to manipulate small or bigger databases; this standard language allows you to operate on all kinds of databases. There are tons of businesses searching for good SQL programmers and database administrators which are high-paying jobs right now.
However, this doesn’t necessarily mean that you need to go to a university to understand the fundamentals of SQL. In fact, there are plenty of simple ways to manage your website data. In our guide, you can learn a few SQL tips that might come in handy when working on your website or customer data.
This is especially recommended for entrepreneurs, financial analysts and small business owners. But, of course, it might be useful for anyone who is interested in the subject.
SQL in a Nutshell
SQL is great for managing data using any database. A database can either have a few data points or hundreds of thousands of them, it doesn’t matter. With SQL, you have a strong tool in hand that can help you harvest data even from huge databases. It’s quick, effective and you only need to know a few tricks to start.
SQL is quite old; it came out back in 1974 and became the most popular language for data management. It had regular updates since then with the last one being released in December 2016. If you want to start with SQL with no experience in programming, there are two versions you should check out. First of all, try the main version that can be used with other database programs effectively.
You also have the Access SQL, which is very similar to the main version. It is a language created for Microsoft Access, which is a highly popular tool that helps tons of small businesses manage their data. But by the second version, we meant MySQL which is in fact the most used SQL on the Internet. It is open-source and a bit different than Access SQL and the main version. However, it will be pretty much the same if you only want to try out the tips that we are going to show you in this guide.
People who own a WordPress website and run a cPanel web based admin interface can easily have access to SQL. If you are one of them, all you need to do is to open the phpMyAdmin app for database access and start running SQL queries. Since the versions that we mentioned – MySQL and SQL – are both really flexible, you have plenty of interfaces and options to start operating with them.
It only depends on the user how the process looks like. SQL queries can be done either in graphical interfaces or in simple text, typing in command lines in an old-fashioned way. What really matters is the end result, which is going to be the same both ways if you do it right. This is exactly what we are going to show you now: how to do it right.
How to Run a SELECT Query?
We start with the simplest one, the SELECT query which is also a very commonly used method if you want to harvest some data. Whenever you have a database with important data points that need to be collected and summarized, you can use this method. A select query can be used in many ways, but now we are going to show you only some essentials that will help you understand the concept.
Any table with classified data would be appropriate. Let’s take a table of books right now. So the table will be called Books and let’s say it’s divided into fields such as title, author, amount (the amount of the book in stock), and price. From now on, we are going to use these fields with all capital letters in the SQL code.
Now if you want to sum up the abovementioned details about each available book in the table, you need to do a select query. This will create you an easy to understand list with all the information neatly summed up. The next step is to create the code that tells the computer what you want and where each field is. Let’s see how our example would look like in SQL code:
As you can see, this query is not very specific. What if you only want information about the Stephen King and Paulo Coelho books in the shop? Of course, there is always Microsoft Excel where you can import the table, then filter Stephen King and Paulo Coelho and then arrange all the information. However, it will take a few steps compared to SQL where you just need to add a short line of code. If you want to filter out the two authors, you only need to use WHERE in the SQL code in the following fashion:
WHERE AUTHOR = ’Stephen King’, ‘Paulo Coelho’;
The semicolon is always at the very end of the code as shown in both examples. In computer language, the semicolon means that it’s the end point of your command and there is nothing else to do. Another important detail is that you need to type the commands in capital letters: WHERE, SELECT, FROM.
Use the apostrophes and commas as shown. You can also find the codes for SQL on Google whenever you need it. Just tell Google Search what you want to do in SQL and there are tons of websites that can show you the correct code for it.
How to Run an UPDATE Query?
Working with databases also includes updating some data points every now and then. This can be done easily with SQL, you just need to get permission first or otherwise you won’t be able to change anything. Once you are able to read and write in the particular database, you can start coding.
There are a lot of things that can go wrong when changing a database so it’s important to be precise with the code. If you use the SELECT command the wrong way, you have a chance to overload the server. Or you might want to collect data but a bad SELECT command gives you the bad results and you might not even notice.
On the other hand, using the UPDATE command the wrong way, you can end up modifying the whole database. To make sure that your database won’t end up in the Recycle Bin, create a backup before you apply the code.
Data is constantly changing, especially in businesses. If you have a database and need to update some parts of it, the UPDATE command can help you out. Let’s go back for the Books example. If you have a classified database about the books in your shop, you might need to update the prices every now and then. If the price of your Fifty Shades of Grey book has been changed and you need to update it, this is the SQL code you need to use:
SET PRICE = ‘9.99’
WHERE TITLE = ‘Fifty Shades of Grey’;
As a result, the book Fifty Shades of Grey will have a new number in the PRICE field, noting that it costs $9.99 from now on. Now if you are not careful, you might forget to add the WHERE part and the code would change all the prices in the database. And then it would take a lot of time to find the correct price for every book again.
Work on Your SQL Skills
By practicing more SQL methods, you can become a master in this language. It can be an incredibly powerful tool for managing the data of your business while saving you a lot of time. After a few days of practice, you will be able to use all the basic commands without making a single mistake.
If you are interested in learning SQL, there are some really good online courses that can teach you some advanced methods. Make sure that you read some reviews before starting any course and then pick the one that mostly suits your needs. Besides UPDATE and SELECT, SQL has much more to offer. Here is a short list, just to give you an idea about some of the most straightforward SQL commands:
- DELETE – allows you to delete specific data points in the database
- INSERT INTO – use this whenever you want to add new data to your table
- CREATE DATABASE – this one speaks for itself, creates an empty database
- ALTER DATABASE – you can use it to modify the database
- CREATE INDEX – you can create new search keys with this one
- DROP INDEX – gets rid of a search key if you don’t need it
- CREATE TABLE – adds a new table to the database
- ALTER TABLE – use this one if you want to modify the table
If you decide to learn and use SQL, don’t expect to use all these commands regularly. SELECT is the most popular command even among professionals. The other commands might be useful occasionally, but it also depends on what kind of database you are working on.
If you work with databases regularly, you will definitely need SQL. As you become good at the language and in managing databases overall, it might also open a new career path for you. The only thing you need to do is to continue practicing because there are tons of opportunities in big data, especially for businesses.