Developers working with applications often issue SQL queries to be processed by their database. Those SQL queries are then processed and a result is returned. Do you know what all of them have in common? SQL operators!
What Are SQL Operators?
SQL operators are the components of SQL queries that help us form our queries — they can be arithmetic, used for comparisons (comparison operators), logical operators, compound operators (mixed operators), string operators on string values, or bitwise operators (characters that represent parts of an SQL query.)
Whatever they are, they’re small parts of our SQL queries. Their goal is to impact how our SQL queries work, execute, and what results they return.
To properly understand SQL operators, take any SQL query and split it into parts. We’ll do that now.
Let’s take an SQL query like so:
1
SELECT username, country, (SELECT car_brand FROM car_data WHERE car_data.id = demo_data.id) AS car_brand
2
FROM demo_data;
Provided to an SQL editor, this SQL query returns these results:
Taken part by part, we can see that this SQL query:
Each of these steps has its own remits and impact on the database — add a couple of comparison operations like WHERE car_id BETWEEN 6 AND 17 and you will have a query with a SQL operator that has to be inserted, interpreted, and worked on by your database.
List of SQL Operators
As we’ve already told you, there are six main types of SQL operators:
Each one of the above SQL operators has its specific remit — and all of them combined create a powerful team of helpers for your use case. Such operators are often used together with certain types of indexes that are used to build more “exotic” kinds of queries (e.g. FULLTEXT queries in MariaDB), and to perform corresponding operations on data with SQL queries.
Some use cases of operators may necessitate certain indexes or options to be in place: many of them, however, can be used in a “vanilla” fashion. For example, the SQL BETWEEN operator can be used within an SQL query like so:
1
SELECT
2
`id`,`country`,`country_code`,`username`,`gender`,`ip_address`
3
FROM `demo_data`
4
WHERE `id` BETWEEN 876 AND 890;
Many other SQL operators will help you in similar situations — turn to the documentation of your database management system of choice for more information.
Summary
The term “SQL operators” refers to six types of characters that can be used for arithmetic, comparison, string, logical, bitwise, or mixed operations involving your data. Each operator has its own goal and we hope that this blog has helped you understand them in detail.
If it did, make sure to read some more of our content over at TheTable blog section and until next time.
FAQ
What are SQL operators?
SQL operators are characters that are used to interact with data mathematically or to complete a very specific task (i.e. lessen the importance of a result with the tilde (~) character, etc).
Do SQL operators make SQL queries execute faster or slower?
While SQL operators can have an impact on query execution time (i.e. they’d be considered a separate task by your database), the usage of SQL operators alone is unlikely to have a significant downside or upside to your query performance.
Where can I learn more about databases?
To learn more about your database management system of choice, refer to the documentation of your DBMS. Also, attend conferences and workshops to learn from industry experts, read blogs, and read books like Hacking MySQL for MySQL engineers, and others for experts of other database management systems.
