Query with the BigQuery API

Create a simple app with BigQuery.

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For detailed documentation that includes this code sample, see the following:

Code sample

C#

Before trying this sample, follow the C# setup instructions in the BigQuery quickstart using client libraries . For more information, see the BigQuery C# API reference documentation .

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries .

  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" 
 ); 
  
 } 
  
 } 
  
 } 
 }

Go

Before trying this sample, follow the Go setup instructions in the BigQuery quickstart using client libraries . For more information, see the BigQuery Go API reference documentation .

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries .

  // Command simpleapp queries the Stack Overflow public dataset in Google BigQuery. 
 package 
  
 main 
 import 
  
 ( 
  
 "context" 
  
 "fmt" 
  
 "io" 
  
 "log" 
  
 "os" 
  
 "cloud.google.com/go/bigquery" 
  
 "google.golang.org/api/iterator" 
 ) 
 func 
  
 main 
 () 
  
 { 
  
 projectID 
  
 := 
  
 os 
 . 
 Getenv 
 ( 
 "GOOGLE_CLOUD_PROJECT" 
 ) 
  
 if 
  
 projectID 
  
 == 
  
 "" 
  
 { 
  
 fmt 
 . 
 Println 
 ( 
 "GOOGLE_CLOUD_PROJECT environment variable must be set." 
 ) 
  
 os 
 . 
 Exit 
 ( 
 1 
 ) 
  
 } 
  
 ctx 
  
 := 
  
 context 
 . 
 Background 
 () 
  
 client 
 , 
  
 err 
  
 := 
  
 bigquery 
 . 
 NewClient 
 ( 
 ctx 
 , 
  
 projectID 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 log 
 . 
 Fatalf 
 ( 
 "bigquery.NewClient: %v" 
 , 
  
 err 
 ) 
  
 } 
  
 defer 
  
 client 
 . 
 Close 
 () 
  
 rows 
 , 
  
 err 
  
 := 
  
 query 
 ( 
 ctx 
 , 
  
 client 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 log 
 . 
 Fatal 
 ( 
 err 
 ) 
  
 } 
  
 if 
  
 err 
  
 := 
  
 printResults 
 ( 
 os 
 . 
 Stdout 
 , 
  
 rows 
 ); 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 log 
 . 
 Fatal 
 ( 
 err 
 ) 
  
 } 
 } 
 // query returns a row iterator suitable for reading query results. 
 func 
  
 query 
 ( 
 ctx 
  
 context 
 . 
 Context 
 , 
  
 client 
  
 * 
 bigquery 
 . 
 Client 
 ) 
  
 ( 
 * 
 bigquery 
 . 
  RowIterator 
 
 , 
  
 error 
 ) 
  
 { 
  
 query 
  
 := 
  
 client 
 . 
 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;` 
 ) 
  
 return 
  
 query 
 . 
 Read 
 ( 
 ctx 
 ) 
 } 
 type 
  
 StackOverflowRow 
  
 struct 
  
 { 
  
 URL 
  
 string 
  
 `bigquery:"url"` 
  
 ViewCount 
  
 int64 
  
 `bigquery:"view_count"` 
 } 
 // printResults prints results from a query to the Stack Overflow public dataset. 
 func 
  
 printResults 
 ( 
 w 
  
 io 
 . 
 Writer 
 , 
  
 iter 
  
 * 
 bigquery 
 . 
  RowIterator 
 
 ) 
  
 error 
  
 { 
  
 for 
  
 { 
  
 var 
  
 row 
  
 StackOverflowRow 
  
 err 
  
 := 
  
 iter 
 . 
 Next 
 ( 
& row 
 ) 
  
 if 
  
 err 
  
 == 
  
 iterator 
 . 
 Done 
  
 { 
  
 return 
  
 nil 
  
 } 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 fmt 
 . 
 Errorf 
 ( 
 "error iterating through results: %w" 
 , 
  
 err 
 ) 
  
 } 
  
 fmt 
 . 
 Fprintf 
 ( 
 w 
 , 
  
 "url: %s views: %d\n" 
 , 
  
 row 
 . 
 URL 
 , 
  
 row 
 . 
 ViewCount 
 ) 
  
 } 
 }

Java

Before trying this sample, follow the Java setup instructions in the BigQuery quickstart using client libraries . For more information, see the BigQuery Java API reference documentation .

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries .

  import 
  
 com.google.cloud.bigquery. BigQuery 
 
 ; 
 import 
  
 com.google.cloud.bigquery. BigQueryException 
 
 ; 
 import 
  
 com.google.cloud.bigquery. BigQueryOptions 
 
 ; 
 import 
  
 com.google.cloud.bigquery. FieldValueList 
 
 ; 
 import 
  
 com.google.cloud.bigquery. Job 
 
 ; 
 import 
  
 com.google.cloud.bigquery. JobId 
 
 ; 
 import 
  
 com.google.cloud.bigquery. JobInfo 
 
 ; 
 import 
  
 com.google.cloud.bigquery. QueryJobConfiguration 
 
 ; 
 import 
  
 com.google.cloud.bigquery. TableResult 
 
 ; 
 public 
  
 class 
 SimpleApp 
  
 { 
  
 public 
  
 static 
  
 void 
  
 main 
 ( 
 String 
 ... 
  
 args 
 ) 
  
 throws 
  
 Exception 
  
 { 
  
 // TODO(developer): Replace these variables before running the app. 
  
 String 
  
 projectId 
  
 = 
  
 "MY_PROJECT_ID" 
 ; 
  
 simpleApp 
 ( 
 projectId 
 ); 
  
 } 
  
 public 
  
 static 
  
 void 
  
 simpleApp 
 ( 
 String 
  
 projectId 
 ) 
  
 { 
  
 try 
  
 { 
  
  BigQuery 
 
  
 bigquery 
  
 = 
  
  BigQueryOptions 
 
 . 
 getDefaultInstance 
 (). 
 getService 
 (); 
  
  QueryJobConfiguration 
 
  
 queryConfig 
  
 = 
  
  QueryJobConfiguration 
 
 . 
 newBuilder 
 ( 
  
 "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" 
 ) 
  
 // Use standard SQL syntax for queries. 
  
 // See: https://cloud.google.com/bigquery/sql-reference/ 
  
 . 
 setUseLegacySql 
 ( 
 false 
 ) 
  
 . 
 build 
 (); 
  
  JobId 
 
  
 jobId 
  
 = 
  
  JobId 
 
 . 
 newBuilder 
 (). 
 setProject 
 ( 
 projectId 
 ). 
 build 
 (); 
  
  Job 
 
  
 queryJob 
  
 = 
  
 bigquery 
 . 
  create 
 
 ( 
 JobInfo 
 . 
 newBuilder 
 ( 
 queryConfig 
 ). 
 setJobId 
 ( 
 jobId 
 ). 
 build 
 ()); 
  
 // Wait for the query to complete. 
  
 queryJob 
  
 = 
  
 queryJob 
 . 
  waitFor 
 
 (); 
  
 // Check for errors 
  
 if 
  
 ( 
 queryJob 
  
 == 
  
 null 
 ) 
  
 { 
  
 throw 
  
 new 
  
 RuntimeException 
 ( 
 "Job no longer exists" 
 ); 
  
 } 
  
 else 
  
 if 
  
 ( 
 queryJob 
 . 
 getStatus 
 (). 
  getExecutionErrors 
 
 () 
  
 != 
  
 null 
 && 
 queryJob 
 . 
 getStatus 
 (). 
 getExecutionErrors 
 (). 
 size 
 () 
 > 
 0 
 ) 
  
 { 
  
 // TODO(developer): Handle errors here. An error here do not necessarily mean that the job 
  
 // has completed or was unsuccessful. 
  
 // For more details: https://cloud.google.com/bigquery/troubleshooting-errors 
  
 throw 
  
 new 
  
 RuntimeException 
 ( 
 "An unhandled error has occurred" 
 ); 
  
 } 
  
 // Get the results. 
  
  TableResult 
 
  
 result 
  
 = 
  
 queryJob 
 . 
  getQueryResults 
 
 (); 
  
 // Print all pages of the results. 
  
 for 
  
 ( 
  FieldValueList 
 
  
 row 
  
 : 
  
 result 
 . 
  iterateAll 
 
 ()) 
  
 { 
  
 // String type 
  
 String 
  
 url 
  
 = 
  
 row 
 . 
 get 
 ( 
 "url" 
 ). 
 getStringValue 
 (); 
  
 String 
  
 viewCount 
  
 = 
  
 row 
 . 
 get 
 ( 
 "view_count" 
 ). 
 getStringValue 
 (); 
  
 System 
 . 
 out 
 . 
 printf 
 ( 
 "%s : %s views\n" 
 , 
  
 url 
 , 
  
 viewCount 
 ); 
  
 } 
  
 } 
  
 catch 
  
 ( 
  BigQueryException 
 
  
 | 
  
 InterruptedException 
  
 e 
 ) 
  
 { 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 "Simple App failed due to error: \n" 
  
 + 
  
 e 
 . 
 toString 
 ()); 
  
 } 
  
 } 
 }

Node.js

Before trying this sample, follow the Node.js setup instructions in the BigQuery quickstart using client libraries . For more information, see the BigQuery Node.js API reference documentation .

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries .

  // Import the Google Cloud client library 
 const 
  
 { 
 BigQuery 
 } 
  
 = 
  
 require 
 ( 
 ' @google-cloud/bigquery 
' 
 ); 
 async 
  
 function 
  
 queryStackOverflow 
 () 
  
 { 
  
 // Queries a public Stack Overflow dataset. 
  
 // Create a client 
  
 const 
  
 bigqueryClient 
  
 = 
  
 new 
  
  BigQuery 
 
 (); 
  
 // The SQL query to run 
  
 const 
  
 sqlQuery 
  
 = 
  
 `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` 
 ; 
  
 const 
  
 options 
  
 = 
  
 { 
  
 query 
 : 
  
 sqlQuery 
 , 
  
 // Location must match that of the dataset(s) referenced in the query. 
  
 location 
 : 
  
 'US' 
 , 
  
 }; 
  
 // Run the query 
  
 const 
  
 [ 
 rows 
 ] 
  
 = 
  
 await 
  
 bigqueryClient 
 . 
 query 
 ( 
 options 
 ); 
  
 console 
 . 
 log 
 ( 
 'Query Results:' 
 ); 
  
 rows 
 . 
 forEach 
 ( 
 row 
  
 = 
>  
 { 
  
 const 
  
 url 
  
 = 
  
 row 
 [ 
 'url' 
 ]; 
  
 const 
  
 viewCount 
  
 = 
  
 row 
 [ 
 'view_count' 
 ]; 
  
 console 
 . 
 log 
 ( 
 `url: 
 ${ 
 url 
 } 
 , 
 ${ 
 viewCount 
 } 
 views` 
 ); 
  
 }); 
 } 
 queryStackOverflow 
 ();

PHP

Before trying this sample, follow the PHP setup instructions in the BigQuery quickstart using client libraries . For more information, see the BigQuery PHP API reference documentation .

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries .

 < ?php 
 # ... 
 require __DIR__ . '/vendor/autoload.php'; 
 use Google\Cloud\BigQuery\BigQueryClient; 
 $bigQuery = new BigQueryClient(); 
 $query = <<<ENDSQL 
 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; 
 ENDSQL; 
 $queryJobConfig = $bigQuery->query($query); 
 $queryResults = $bigQuery->runQuery($queryJobConfig); 
 if ($queryResults->isComplete()) { 
 $i = 0; 
 $rows = $queryResults->rows(); 
 foreach ($rows as $row) { 
 printf('--- Row %s ---' . PHP_EOL, ++$i); 
 printf('url: %s, %s views' . PHP_EOL, $row['url'], $row['view_count']); 
 } 
 printf('Found %s row(s)' . PHP_EOL, $i); 
 } else { 
 throw new Exception('The query failed to complete'); 
 }

Python

Before trying this sample, follow the Python setup instructions in the BigQuery quickstart using client libraries . For more information, see the BigQuery Python API reference documentation .

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries .

  from 
  
 google.cloud 
  
 import 
  bigquery 
 
 def 
  
 query_stackoverflow 
 () 
 - 
> None 
 : 
 client 
 = 
  bigquery 
 
 . 
  Client 
 
 () 
 results 
 = 
 client 
 . 
  query_and_wait 
 
 ( 
  
 """ 
 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""" 
 ) 
 # Waits for job to complete. 
 for 
 row 
 in 
 results 
 : 
 print 
 ( 
 " 
 {} 
 : 
 {} 
 views" 
 . 
 format 
 ( 
 row 
 . 
 url 
 , 
 row 
 . 
 view_count 
 )) 
 if 
 __name__ 
 == 
 "__main__" 
 : 
 query_stackoverflow 
 ()

Ruby

Before trying this sample, follow the Ruby setup instructions in the BigQuery quickstart using client libraries . For more information, see the BigQuery Ruby API reference documentation .

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries .

  require 
  
 "google/cloud/bigquery" 
 # This uses Application Default Credentials to authenticate. 
 # @see https://cloud.google.com/bigquery/docs/authentication/getting-started 
 bigquery 
  
 = 
  
 Google 
 :: 
 Cloud 
 :: 
  Bigquery 
 
 . 
  new 
 
 sql 
  
 = 
  
 "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" 
 results 
  
 = 
  
 bigquery 
 . 
 query 
  
 sql 
 results 
 . 
 each 
  
 do 
  
 | 
 row 
 | 
  
 puts 
  
 " 
 #{ 
  row 
 
 [ 
 :url 
 ] 
 } 
 : 
 #{ 
  row 
 
 [ 
 :view_count 
 ] 
 } 
 views" 
 end

What's next

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Explore further

Code sample

C#

Go

Java

Node.js

PHP

Python

Ruby

What's next

Query with the BigQuery API