MySQL

In business intelligence and data analysis, the analysis of the operation performance metrics against the historical trend is a vital process that contributes to understanding the trends, the opportunity for growth and the taking of right decisions. Such comparison is important because year-over-year difference analysis acts as the basic tool for analysts and business entities …

Calculating Year-Over-Year Difference in SQL: An Easy Guide Read More »

The NULLs in SQL play an essential role in defining the ‘unknown values’ from the database. In SQL, almost every database contains such types of values to represent the empty spaces. The comparison operators ( =, <>, <, > ) are widely used in SQL queries to solve complex models. In this article, we are …

Comparison Operators With NULLs In SQL: IS NULL and IS NOT NULL Read More »

PostgreSQL is the open-source with the free functionality that you can use to perform certain tasks. The ability of the PostgreSQL language is upgraded with various extensions that will be applicable for different kinds of models for operation complexity. Here, we are going to analyze the aggregate function PostgreSQL GROUP BY extension deeply. The GROUP …

GROUP BY Extensions in PostgreSQL: An Easy Guide Read More »

While writing queries in SQL during the learning phase, we mostly join the table in which there are common columns or some kind of relationship between them. But, real-life scenarios are more complex and there are times when we are required to join the tables without any common column between them. In this tutorial, we …

How to Combine Two Tables Without a Common Column Read More »

While writing SQL queries, one of the fundamental operations is to sort the data, which is often done using the “ORDER BY” clause. However, in certain situations, we deal with “NULL” values and wonder if they come first or last when we use the ORDER BY clause. In this tutorial, we will learn about how …

Handle NULL When Working with ORDER BY Clause in SQL Read More »

SQL queries use the HAVING and WHERE clauses to filter the data. However, the WHERE clause cannot be used with the aggregate functions, which is where the HAVING clause comes into the picture! In this tutorial, we will learn about filtering data with HAVING and WHERE clause and their uses and differences between them with …

Filtering Data with WHERE & HAVING Clause Read More »

While writing SQL queries there are times when we face many errors. The possibility of facing errors depends on the way you are writing queries, either it can be a typo mistake or wrong syntax. Although error messages are helpful in troubleshooting, they may not always be helpful. “Not A Group By Expression” Error is …

How to Fix ‘Not A Group By Expression’ Error Read More »

PostgreSQL allows us to export the contents of a table to a CSV file. The abbreviation CSV stands for comma-separated values. PostgreSQL has many commands for exporting data to CSV. We may export both the table’s content and the query’s results as CSV files which is extremely useful for transferring data from one database application …

Export a PostgreSQL Table to a CSV File (Easy Methods) Read More »

PostgreSQL is an open-source relational database system, which is an ideal platform for developers to perform data manipulation and analysis. One of the primary jobs while writing queries and extracting insights from datasets is to import CSV to add data to PostgreSQL tables. In this tutorial, you will learn how to import a CSV file …

Import CSV File into PostgreSQL Table (Easy Methods) Read More »

While writing SQL queries, we perform multiple calculations on data using various aggregated functions and we often need to rank our data for better understanding and analysis of the databases. Ranking functions are one of the important types of window functions which can be easily implemented. In this tutorial, we will learn about the multiple …

An Easy Guide to SQL Ranking Window Functions Read More »