28 Jul 2021 Zahin Rahman An Overview of SQL Text Functions In this article, we will discuss the ins and outs of the most common SQL text functions, which make it possible for you to find and work on string values. Before we dive into text functions, let’s quickly recap what an SQL function is. Simply put, a function is a predefined built-in piece of code that you can use in your SQL query. For example, the functions SUM(), AVG(), and COUNT() are applied to numerical variables to calculate the sum, average, and number of records respectively. Read more 30 Jun 2021 Zahin Rahman Top 15 SQL Interview Questions in 2021 If you are on the lookout for a job in the field of data, you’re almost guaranteed to face SQL interview questions. You might even be asked to complete some kind of SQL coding test. According to KDnuggets, irrespective of the specific role in data – data analyst, data engineer, data scientist, or business intelligence analyst – SQL lands in the top three skills found in postings across Indeed, SimplyHired, and Monster. Read more 7 May 2021 Zahin Rahman What Is the WITH Clause in SQL? In this article, you will learn about the SQL WITH clause, also known as common table expression (CTE). We will go over some examples to demonstrate some of their use cases in light of their benefits. Introduction to the SQL WITH Clause The WITH clause in SQL was introduced in standard SQL to simplify complex long queries, especially those with JOINs and subqueries. Often interchangeably called CTE or subquery refactoring, a WITH clause defines a temporary data set whose output is available to be referenced in subsequent queries. Read more 13 Apr 2021 Zahin Rahman What FULL JOIN Is and When to Use It Learn about FULL JOIN, how to implement it, how it compares with the other types of SQL JOINs, and some of its unique use cases. Before we jump into FULL JOINs, let’s quickly recap what an SQL JOIN is. At its core, a JOIN combines data from two or more tables within a database. Tables are usually linked together using unique identifiers in each table, i.e. primary and foreign keys. Read more 8 Apr 2021 Zahin Rahman SQL CTE Explained In this article, you will learn about SQL Common Table Expressions (CTEs). This powerful SQL tool will help you simplify complex queries. Additionally, I will introduce you to the two main types of CTEs and some of their use cases. CTE Primer The Common Table Expression (CTE) was introduced to standard SQL to simplify long, complex queries (especially joins and subqueries). It is a temporary data set returned by a query that contains data separate from the main query. Read more 22 Jan 2021 Zahin Rahman Why Learn SQL Window Functions in 2021? SQL window functions provide some extremely powerful and convenient features for data practitioners. This article explains why you should learn window functions and when you should use them. I’ll also provide some examples to help you visualize the concepts. Window functions are part of advanced modern SQL – knowledge of which will definitely enrich the repertoire of any SQL user. Window functions have a broad range of uses and can be applied to almost all facets of business. Read more 21 Jan 2021 Zahin Rahman Where Can I Find Good SQL CTE Exercises? Find the top online resources for SQL Common Table Expression (CTE) exercises! CTEs allow you to structure and organize SQL queries efficiently, which is essential if you want to advance your SQL knowledge. A Common Table Expression, or CTE, is a SQL syntax that creates a temporary data set. This set contains separate data than the main query, which can typically be referenced or reused in a subsequent query. A CTE is considered temporary because the result is not permanently stored anywhere and only exists for the duration of the query. Read more 16 Dec 2020 Zahin Rahman Best Online Courses for SQL Window Functions In this article, I will summarize the top online tutorials and courses available on SQL window functions for enthusiasts of data analysis, data science, and data engineering. The information is here to help you embrace the topic with ease and feel comfortable using window functions in SQL databases. SQL window functions can help you solve some of the most common analysis challenges in business: What are the N most popular products for each month of the year? Read more 11 Nov 2020 Zahin Rahman Top 7 Online Courses for Data Engineers This article summarizes the top online courses available for data engineers. We have picks suitable for beginners as well as intermediate learners. If you’re interested in database design and management, check these courses out! Most individuals who aspire to enter the realm of data aim for data scientist or data analyst roles. While these roles are indeed very rewarding because of their tangible links to customers and business direction, the role of data engineers is equally vital for businesses that operate in a data-rich environment. Read more 14 Oct 2020 Zahin Rahman SQL HAVING Tutorial Learn how to use the SQL HAVING clause to filter groups using your own specified conditions. The SQL HAVING clause is often a challenging concept to grasp, especially for beginners. Additionally, its specific use cases can be difficult to visualize without specific examples based on real-world datasets. In this tutorial, you will learn how to apply the SQL HAVING clause to filter groups of records based on specified conditions. You’ll see examples where we apply this concept to solving business problems on a realistic dataset. Read more «« « 1 2 » »»