According to Statista, the total amount of data created, captured and consumed globally is projected to cross 394 zettabytes by 2028. But did you know that only a fraction of this data is retained, as low as 2%?
This clearly explains the need for a language to communicate with the data stored in databases effectively. The most popular such language is SQL (Structured Query Language), used widely around the world by professionals dealing with huge databases.
As the SQL developer jobs are skyrocketing, let’s scroll down to find out what SQL is all about.
What is SQL?
Structured Query Language is a programming language that communicates with the databases on your behalf to fetch you relevant data. Think of it like a specialist who brings to you the desired products from your warehouse on your command.
In other words, SQL helps you interact with these databases to find, add, change, or remove information.
Why is SQL so popular?
Unlike other programming languages, SQL is one such language with the simplest syntax, that is very easy to understand for professionals from non-technical backgrounds.
This makes SQL very versatile, being widely used among multiple industries. Whether you're a business owner, a manager, or someone who just needs to keep track of a lot of information, SQL can be a huge help.
Here are some key features of SQL:
- Data Manipulation- SQL allows you to perform various operations on data within a database. This includes inserting, updating, and deleting data.
- Data Retrieval- One of the most powerful aspects of SQL is its ability to retrieve data from a database. You can use SQL to select, filter, and join data across databases.
- Data Definition- SQL also provides tools for defining and managing the structure of your database. This includes creating, modifying, and dropping tables.
Alright, being such an important language, what do you need to get you started? Just your passion and the understanding of the core concepts discussed below.
Core Concepts in SQL
Here’s a very simple list of the fundamental commands you need to be comfortable with before diving into advanced SQL concepts.
Imagine you are the principal of a school and you need to fetch the data of your students.
SELECT (Choose columns)
The SELECT command is used to choose columns within a table in a database
In the above case ‘*’ represents all the columns in the table, and ‘student_name’ represents the column containing the names of students.
FROM (Choose Tables)
FROM directs our specialist to choose the right table among the multiple tables in a database.
Here, the instruction is given to show the students' age and gender columns from the student record table
WHERE (Filter Rows)
This command is used to create a filter among rows, so that rows with specific details only show up. For example:
By using the AND command, you can add multiple filters
In the above scenario, when the students' age and gender columns are selected from the student record table, a filter is created where only those rows where the gender data is male and the age number is greater than 10 years show up and the rest are left out.
GROUP BY (Group Rows)
As the name implies, this command allows you to group multiple rows of similar nature together. For example:
By using the AVG function, you can take the average of a particular column
Here, the class column and the GPA column of each student are selected from the student record table. Now using the GROUP BY command all the students of the same class are grouped together. This will give us the average GPA of a particular class in the school.
HAVING (Filter Grouped Rows)
This command is used to create a filter among rows that are sorted into multiple groups. It is a very useful command to streamline the information that you can extract from the database. For example:
Following up from the previous point, where we have derived the average GPA of all the classes in the school. Now the principal wants to see only those classes that have their average GPA less than 4. To achieve this, he uses the HAVING command that filters out the grouped rows of classes and shows only those classes that have their GPA < 4.
ORDER BY (Sort Rows)
This command is used to present data in a specific order. Here in the following example, the average GPA of classes is shown in descending order by using the ORDER BY command.
Once you are familiar with these commands, congratulations! You have now started your journey in SQL and there is a lot of interesting stuff on the way.
Career Opportunities: SQL Developer Jobs
The global demand for SQL professionals is surging, with over 400,000 active jobs on LinkedIn in the United States alone, indicating a robust market for individuals skilled in SQL and related technologies.
According to the Bureau of Labor Statistics, the projected growth for SQL-related roles is expected to rise at a rate of 8% from 2022 to 2032, which is faster than the average for all occupations.
Here are the best roles that you can explore:
Learning Resources: SQL Tools
If you’re interested in learning more about SQL, there are plenty of resources available. You can also practice using free database tools like SQLite or MySQL. Here are some of the SQL practice tools:
1. SQLZoo- This is a beginner-friendly platform that offers interactive tutorials and exercises. You can write SQL queries and see the results immediately. It covers essential SQL concepts like SELECT, JOINs, aggregation, subqueries, and window functions
2. SQLBolt- It offers interactive lessons and exercises that make it easy to learn and practice SQL right in your browser. The 18 lessons will provide you with a solid baseline level of SQL knowledge
3. DBeaver- This is a free multi-platform database tool that supports various types of databases like MySQL, Oracle, DB2, SQLite, and more. It also provides ER diagrams for defining relationships and database structure comparison
Final Thoughts
So now you have a grasp of the core concepts of SQL to get you started. What’s next?
As the next step, you need to consistently practise all the commands and queries to master them. You can use any of the free tools mentioned in this blog.
At the end of the day, when you’re ready to advance in your career with SQL in your skillset, here are our blogs on Bosscoder Academy to guide you.
FAQ
Which is better, MySQL or SQL?
SQL is a programming language, while MySQL is a database management system that uses SQL. Both SQL and MySQL are powerful and scalable, but they have different use cases.
What is database schema in SQL?
In SQL, a database schema is a logical representation of the structure of a database, defining how data is organized, stored, and accessed by specifying the tables, columns, data types, relationships between tables (using primary and foreign keys), and constraints that govern the data within the database.
What are some of the SQL interview questions?
You can expect questions on normalization, denormalization, and the differences between various SQL statements like DELETE, TRUNCATE, and DROP. Advanced queries. You may be asked about subqueries, both nested and correlated, as well as how to perform specific tasks like finding the nth highest value in a column.
What is substr SQL query?
In SQL, "SUBSTR" (or sometimes written as "SUBSTRING") is a function that allows you to extract a specific portion of a string, called a substring, from a larger string by specifying the starting position and the desired length of the extracted part.
