Estimating BigQuery Data Processed Before Running a Query

In Google BigQuery, SQL is used to interact with datasets and retrieve data. One of the most basic and commonly used SQL statements is:

SELECT * FROM `project.dataset.table`;

This statement retrieves all columns and all rows from a specified table in BigQuery.

 

·      SELECT * : This means "select all columns" from the table.

·      FROM : This specifies the source table from which data will be retrieved.

·      `project.dataset.table`: This refers to the fully qualified table name in BigQuery. It consists of:

o   project: The Google Cloud project containing the dataset.

o   dataset: A collection of related tables within the project.

o   table: The actual table storing the data.

 

Imagine you have a table named sales_data inside a dataset called store_db in a project named retail_project. To fetch all data from this table, you would use:

SELECT * FROM `retail_project.store_db.sales_data`;

For example, when I enter the query:

SELECT * FROM `i-mariner-453509-e9.test_dataset.emps` LIMIT 2;

Before execution, the BigQuery Query Editor provides an estimate of the amount of data the query will process. For instance, it might display a message like:

 

"This query will process 573 B when run."

 

You can find this estimate in the top right corner of the query editor.

 

You can also format the query for better readability by selecting MORE → Format Query in the BigQuery Query Editor.

 

Previous                                                    Next                                                    Home