intro
COALESCE is a well-known SQL function that returns the first non-NULL value in a list of values. However, there are a lot of other SQL clauses beside it that can help you. Learn everything about them here.
Judging by the fact that you’re reading this blog, we can safely assume that you’re a database enthusiast. No matter what kind of database management system you find yourself using, you know that SQL clauses and functions like the COALESCE SQL function are instrumental for your work. Here are some other SQL clauses you need to be aware of.
What are SQL Clauses?
In the database world, an SQL clause is a function helping fetch rows or records from a table in a database. SQL clauses include WHERE, ORDER BY, GROUP BY, HAVING, TOP, WITH, LIKE, LIMIT, AND, and the like. Some of them help your database locate data, order or group rows in a specific order, some help filter results acquired by using other SQL clauses like GROUP BY, and some facilitate exotic search operations.
In other words, the COALESCE SQL function is only one of various SQL functions you should be concerned about — we’ve covered the COALESCE SQL function in this blog previously, but there are many other things you should be aware of, too. Think about it — returning the first non-NULL value in a list of values isn’t the solution to your problem. It’s a part of it. Other parts of your problem require you to go above and beyond the COALESCE SQL function.
Beyond the COALESCE SQL Function
Truth be told, COALESCE isn’t a SQL function that is the holy grail to your availability, security, or database performance problems. Problems don’t come alone — and other problems will inevitably concern other SQL functions and clauses, too. They will include:
In other words, both of those problems can be eliminated by following the basics of SQL clauses. Here’s how:
Coming back to SQL functions and clauses, they’re not exactly related to availability issues, but for some use cases, even that’s debatable. Have you ever seen an application that times out after you perform an action? It’s likely that a timeout is a direct result of an SQL clause not working in conjunction with your database and query structure — it isn’t far-fetched for a query to return hundreds of millions of results at once and if your application isn’t ready for that, you’re going to have problems.
Crafting SQL Clauses with DbVisualizer
To alleviate the pain caused by those problems, you should consider using SQL clients like DbVisualizer. DbVisualizer is a top-rated SQL client that comes with support for 50+ data sources like MySQL, PostgreSQL, Snowflake, ElasticSearch, and more, and its ease of use will leave even the biggest critics in the dust. To use DbVisualizer for your use case, first add a database management system associated with your use case by clicking the Plus sign:
Select a driver your database will be running (the flavor of your database) — you can also define custom drivers if you so desire:
Once you’re done, enter the login credentials for your database and connect to it:
And finally, if everything’s done successfully, you should see your new databases in the left pane of DbVisualizer — a green tick will indicate that DbVisualizer is all set to monitor and visualize your data:
Once that’s done, feel free to use the SQL commander to run commands. The SQL client provided by DbVisualizer will help you craft SQL queries in a nice-to-see manner (format them for you), and once you act on your data you will quickly understand that DbVisualizer isn’t your typical SQL client:
Queries and SQL clauses have to do with permissions and permissions in DbVisualizer is only one of very many features you can peruse; some features like SSH, monitoring, and SQL history are available free of charge, while others like database events and jobs, custom query builders, and the like require a paid subscription, but nonetheless, DbVisualizer has you covered. From setting permissions for the SQL Commander (SQL client) in the Tool Properties menu to custom charts and explain plans, DbVisualizer has it all. Give it a whirl today, continue crafting safe and performant SQL clauses, and until next time.
Summary
The COALESCE SQL function is one of many SQL functions you can peruse to achieve your database goals. Aside from that, many DBAs know that COALESCE is only a part of solutions to their problems as it’s only useful to retrieve the first non-NULL value from a set of values. If you want to do other things, you need to take care of other SQL clauses like WHERE, ORDER BY, LIKE, and the like.
We hope that this blog has opened your eyes into the world of SQL clauses and that you will come back to be further educated in the database space, and we’ll see you in the next one. Bye for now.
FAQ
What is the COALESCE SQL Function?
The COALESCE SQL function is an SQL function that returns the first non-NULL value in a set of values. This SQL function is nothing special and it’s frequently used with other SQL clauses like WHERE, ORDER BY, and the like.
What Other SQL Clauses are Available?
The complete list of SQL functions and clauses that are available will depend on your database management system in question, however, some of the SQL clauses you will come across include LIMIT to limit the number of rows returned by a query, AND to “join” a part of a SQL query with another part, clauses related to index structures like ADD INDEX and so on.
Where Can I Learn More About Coalesce SQL and Other SQL Clauses?
To learn more about COALESCE SQL and other SQL functions, you should read the documentation, blogs, books, as well as attend conferences to network with professionals in your field. Reading books like Hacking MySQL: Breaking, Optimizing, and Securing MySQL for Your Use Case will be a good place to start, and reading blogs like TheTable will also be a great place if you want to expand your existing knowledge.
