How to convert julian date to normal date in MySQL

In this article, we will learn how to convert a Julian date to the calendar date with MySQL. First, let’s see how it looks like a date in Julian format. Julian calendar and Julian date format The Julian calendar was used since the time of Julio Cesar, specifically 45 years before Christ. It was used until 1582 when Pope Gregory XIII introduced the Gregorian calendar that we currently use. The dates in the Julian calendar can have several...

Comparing Tables and Columns in MySQL

In MySQL, we can compare tables and columns at the record level by looking at their values side by side. We will use MySQL JOIN clauses to do this. In this article, we look at the different JOIN operators through various examples. As programmers, when building an application, we often find problems or conditions that require us to compare records in the database table. On this occasion, we will discuss the query of how to compare tables in...

How to compare two columns in MySQL

In MySQL, we can compare two columns  to identify the records they have in common and also, the records one table has but the other does not. In this article, we will learn how to compare two columns to find common records, and we will also find their differences. To illustrate the examples in this article, we are going to create two tables (contacts and clients) with the following structure and data: CREATE TABLE `clients` ( `id`...