SQL INNER JOIN – A Beginner’s Guide

Introduction In this article, we are going to see how the INNER JOIN works in SQL, and how you can use it to associate rows belonging to different tables and build compound result sets.

SQL EXISTS and NOT EXISTS

Introduction In this article, we are going to see how the SQL EXISTS operator works and when you should use it. Although the EXISTS operator has been available since SQL:86, the very first edition of the SQL Standard, I found that there are still many application developers who don’t realize how powerful SQL subquery expressions really are when it comes to filtering a given table based on a condition evaluated on a different table.

SQL CROSS JOIN – A Beginner’s Guide

Introduction In this article, we are going to see how a CROSS JOIN works, and we will also make use of this SQL join type to build a poker card game.

A beginner’s guide to database deadlock

Introduction In this article, we are going to see how a deadlock can occur in a relational database system, and how Oracle, SQL Server, PostgreSQL, or MySQL recover from a deadlock situation.

How to map SQL Server JSON columns using JPA and Hibernate

Introduction In this article, we are going to see how easy it is to map an SQL Server JSON column when using the Hibernate Types project. Not only that the hibernate-types project supports JSON column types for PostgreSQL and MySQL and Oracle, but, as you will see in this article, the JsonStringType works just fine when using Microsoft SQL Server.

JDBC Driver Maven dependency list

Introduction Ever wanted to connect to a relational database using Java and didn’t know which JDBC Driver Maven dependency to use? If so, this article is surely going to help you from now on.

How to get the query execution plan on SQL Server

Introduction In this article, we are going to see how we can get the query execution plan when using the SQL Server relational database system. The execution plan allows you to understand the operations done by the database engine when executing a specific SQL query.

How to limit the SQL query result set to Top-N rows only

Introduction In this article, we are going to see how we can limit the SQL query result set to the Top-N rows only. Limiting the SQL result set is very important when the underlying query could end up fetching a very large number of records, which can have a significant impact on application performance.

SQL ORDER BY RANDOM

Introduction In this article, we are going to see how we can sort an SQL query result set using an ORDER BY clause that takes a RANDOM function provided by a database-specific function. This is a very handy trick, especially when you want to shuffle a given result set. Note that sorting a large result set using a RANDOM function might turn out to be very slow, so make sure you do that on small result sets. If you have to shuffle a large result set and limit it afterward, then it’s… Read More

JDBC Driver Connection URL strings

Introduction Ever wanted to connect to a relational database using Java and didn’t know the URL connection string? Then, this article is surely going to help you from now on.