In SQL, variables are used to store data that can be used and manipulated throughout a program. They are essential for dynamic SQL queries, where the values of the variables can be determined at runtime.
The syntax for declaring and using variables is different in different SQL databases.
Here are some examples:
MySQL variable in SQL query
In MySQL, you can declare a variable using the SET or SELECT statement.
SQL Server variable in SQL query
In SQL Server, you can declare a variable using the DECLARE statement and set its value using the SET statement.
Oracle variable in SQL query
In Oracle, you can declare a variable in a PL/SQL block.
PostgreSQL variable in SQL query
In PostgreSQL, you can use variables in functions, and the syntax is similar to Oracle's PL/SQL.
In all cases, once a variable is declared and assigned a value, it can be used in a query like this:
Remember to check the documentation of the SQL database you are using for the exact syntax and usage of variables.
You might also like
Castor is a modern data catalog. TLDR: SQL parameters can be a mess, quickly. Introducing tricks for SQL, DBT, pandas, Airflow, Metabase
Discover a comprehensive SQL editor benchmark and market analysis to help you choose the best solution for your data management needs.
“[I like] The easy to use interface and the speed of finding the relevant assets that you're looking for in your database. I also really enjoy the score given to each table, [which] lets you prioritize the results of your queries by how often certain data is used.” - Michal P., Head of Data