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How to 10x your BigQuery Productivity with Variables

In this article, you’re going to learn how to create and use variables to 10x your productivity in BigQuery.
 
How much time do you spend repeatedly making small changes to your SQL?
 
Whether you’re updating a column’s value or changing a date in your partition, this can get annoying very fastEven more so when these values appear in multiple places in your code.
 
This is where variables save the day (and your precious time). Variables can help you make quick updates without touching your SQL.
 
The best part? It’s possible to set up variables without writing a single line of SQL.
 
But first…

What are variables?

Sometimes referred to as parameters, 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 when querying in the editor.

Next, we’re going to show you:

  1. How to set up variables without using any SQL.
  2. How to use variables in your query editor to save you LOADS of time.

How to create a variable in BigQuery

Step 1: Open the superQuery IDE — Make sure you have a superQuery account (it’s free to start)

Step 2: Click the “Add Variable” button to open the Variable Settings pop-up.

Add Variable SuperQuery

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 Facebook ad data, you could create a String variable named “min_cpc” that has an initial value of “3” (i.e. $3)

Define Variable SuperQuery

Step 5: Use your variable in a query.

Use variables in your SQL by placing an “@” character 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 to explore the new results.

You can use multiple variables in a single query. You can also use a single variable across several query tabs

Use Variables in BigQuery

Why use variables?

Without variables, if you wanted to update your SQL — like changing the value of “min_cpc” above — you had to manually find the value in your code and then change the value.

Imagine having to find the specific value you’d like to change when the SQL is 100+ lines.

Now, you can insert a variable in place of any value and update its value without needing to revisit a specific line in 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.

Using variables when visualizing your queries

Wrapping up

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.

To use variables in your query editor, create a superQuery account — it’s as simple as logging with your Google account directly from our website.

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