Typical queries in the SELECT * FROM table format are sometimes not enough. When the data for a query is not in one table, but in several, or when it is necessary to specify several selection parameters at once, you will need more sophisticated queries.
This article will explain how to build such queries and provide examples of complex SQL queries.
SQL query optimization is a big topic. Each technique or problem needs a separate article to cover the bases. But when you’re just starting to level up your game with queries, you need something simpler to rely on. This is the goal of this article.
If you are reading this article, most probably, you are already familiar with SQL. You know how to write basic SQL queries. There are many ways to execute a SQL query to get desired results on your database.
However, not all SQL queries are created equal. Most can be optimized to follow the best practice. This article focuses on 9 SQL query optimization tips. After reading, you will know all the dos and don’ts of writing SQL queries.
This article will focus on writing SQL queries against the database reference table with a fairly simple structure to understand and implement.
Additionally, we are going to clarify the concepts behind writing effective SQL queries along with some professional life tips.
This article explains writing simple SQL queries from the most basic ones and gradually improving the script to solve some mathematical and date-related problems. Additionally, we are going to clarify the concepts surrounding SQL queries.
Although this article is primarily for beginners, it contains hints that will be helpful for any experience level.
We often see poorly written complex SQL queries running against a table or tables in databases. Those queries make the time of execution very long and cause consuming huge CPU and other resources. Still, complex queries provide valuable information to the application/person running them in many cases. Therefore, they are useful assets in all varieties of applications.
Read MoreDo you use SQL subqueries or avoid using them?
Let’s say the chief credit and collections officer asks you to list down the names of people, their unpaid balances per month, and the current running balance and wants you to import this data array into Excel. The purpose is to analyze the data and come up with an offer making payments lighter to mitigate the effects of the COVID19 pandemic.
Do you opt to use a query and a nested subquery or a join? What decision will you make?
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