Query a public dataset with the BigQuery C# client library

Open the Cloud Shell Editor

1. In Cloud Shell, create a new C# project and file:

   dotnet new console -n BigQueryCsharpDemo
   

   The output is similar to the following. Several lines are omitted to simplify the output.

   Welcome to .NET 6.0!
   ---------------------
   SDK Version: 6.0.407
   ...
   The template "Console App" was created successfully.
   ...
   

   This command creates a C# project that's named BigQueryCsharpDemo and a file that's named Program.cs.

2. Open the Cloud Shell Editor:

   cloudshell workspace BigQueryCsharpDemo
   

To learn how to prepare files for queries, click Next.

Prepare files for queries

1. To open a terminal in the Cloud Shell Editor, click Open Terminal.

2. Open your project directory:

   cd BigQueryCsharpDemo
   

3. Install the BigQuery client library for C#:

   dotnet add package Google.Cloud.BigQuery.V2
   

   The output is similar to the following. Several lines are omitted to simplify the output.

   Determining projects to restore...
   Writing /tmp/tmpF7EKSd.tmp
   ...
   info : Writing assets file to disk.
   ...
   

To learn how to query a public dataset in BigQuery, click Next.

Query a public dataset in BigQuery

1. Set the variable GOOGLE_PROJECT_ID to the value GOOGLE_CLOUD_PROJECT and export the variable:

   export GOOGLE_PROJECT_ID=$GOOGLE_CLOUD_PROJECT
   

2. Click Open Editor.

3. In the Explorer pane, locate your BIGQUERYCSHARPDEMO project.

4. Click the Program.cs file to open it.

5. To create a query against the bigquery-public-data.stackoverflow dataset that returns the top 10 most viewed Stack Overflow pages and their view counts, replace the contents of the file with the following code:

   
   using System;
   using Google.Cloud.BigQuery.V2;
   
   namespace GoogleCloudSamples
   {
       public class Program
       {
           public static void Main(string[] args)
           {
               string projectId = Environment.GetEnvironmentVariable("GOOGLE_PROJECT_ID");
               var client = BigQueryClient.Create(projectId);
               string query = @"SELECT
                   CONCAT(
                       'https://stackoverflow.com/questions/',
                       CAST(id as STRING)) as url, view_count
                   FROM `bigquery-public-data.stackoverflow.posts_questions`
                   WHERE tags like '%google-bigquery%'
                   ORDER BY view_count DESC
                   LIMIT 10";
               var result = client.ExecuteQuery(query, parameters: null);
               Console.Write("\nQuery Results:\n------------\n");
               foreach (var row in result)
               {
                   Console.WriteLine($"{row["url"]}: {row["view_count"]} views");
               }
           }
       }
   }
   

6. Click Open Terminal.

7. In the terminal, run the Program.cs script. If you are prompted to authorize Cloud Shell and agree to the terms, click Authorize.

   dotnet run
   

   The result is similar to the following:

   Query Results:
   ------------
   https://stackoverflow.com/questions/35159967: 170023 views
   https://stackoverflow.com/questions/22879669: 142581 views
   https://stackoverflow.com/questions/10604135: 132406 views
   https://stackoverflow.com/questions/44564887: 128781 views
   https://stackoverflow.com/questions/27060396: 127008 views
   https://stackoverflow.com/questions/12482637: 120766 views
   https://stackoverflow.com/questions/20673986: 115720 views
   https://stackoverflow.com/questions/39109817: 108368 views
   https://stackoverflow.com/questions/11057219: 105175 views
   https://stackoverflow.com/questions/43195143: 101878 views
   

You have successfully queried a public dataset with the BigQuery C# client library.

To avoid incurring charges to your account and learn about next steps, click Next.