What are variables?
Put simply, variables are placeholders in SQL for values that can change. Variables store the value you assign them, and pass them on when used in a query.
They’re extremely helpful when you want to update literal values in your queries.
Typically, DECLARE and SET statements are used to create variables and assign them values, with the syntax looking like:
DECLARE @Local_Variable SET<@Local_Variable =
Google allows you to run something similar to variables in BigQuery, called parameterized queries, but it only works via their API and not in the editor.
Now, we’re going to show you how to set up variables without using any SQL.
How to create a variable in BigQuery
Step 3: Select your variable’s data type.
In superQuery, variables can hold the following data types: STRING, NUMBER, DATE, DATETIME.
Step 4: Give your variable a good name and click “Save”.
For example, if you’re analyzing user event data, you would create a String variable named “event” that has a value of “login”.
Step 5: Use your variable in a query.
Use variables in your SQL by placing an “@” in front of the variable’s name, like in the example below.
To edit your variable’s value, change it in the text box next to your variable’s name. Then run the query again.
You can use multiple variables in a single query. You can also use a single variable across several query tabs
How can I use variables?
Let’s continue with our example of analyzing usage data for an app. Suppose you filter this data according to various in-app events, a specific user ID, or by date.
As mentioned earlier, if you wanted to update your SQL — like changing the user ID above — you had to manually find the value in your code.
Now, you can insert a variable in place of the user ID value and update its value without needing to revisit your SQL again.
Using variables with visualizations
Variables can also be useful when you’re visualizing your queries in superQuery.
Update your queries while viewing them in Visualize mode by changing the variable’s value and clicking the “Refresh” icon to its left.
This is the same as running a new query, and your visualizations will update accordingly.
Now that you know how to create and use variables, it’s time to try them out on your own BigQuery data.
They’ll give your SQL some flexibility, and save you tons of time when making small changes.