Query a public dataset with the BigQuery Go client library

Open the Cloud Shell Editor

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

    mkdir  
   bigquery-go-quickstart  
    \ 
    && 
   touch  
    \ 
     
   bigquery-go-quickstart/app.go 
   

   This command creates a Go project that's named bigquery-go-quickstart and a file that's named app.go .

2. Open the Cloud Shell Editor:

    cloudshell  
   workspace  
   bigquery-go-quickstart 
   

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 
     
   bigquery-go-quickstart 
   

3. Create a go.mod file:

    go  
   mod  
   init  
   quickstart 
   

   The output is similar to the following:

    go: creating new go.mod: module quickstart
   go: to add module requirements and sums:
           go mod tidy 
   

4. Install the BigQuery client library for Go:

    go  
   get  
   cloud.google.com/go/bigquery 
   

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

    go: downloading cloud.google.com/go/bigquery v1.49.0
   go: downloading cloud.google.com/go v0.110.0
   ...
   go: added cloud.google.com/go/bigquery v1.49.0
   go: added cloud.google.com/go v0.110.0 
   

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

Query a public dataset in BigQuery

1. Click Open Editor.

2. In the Explorerpane, locate your BIGQUERY-GO-QUICKSTART project.

3. Click the app.go file to open it.

4. 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, copy the following code into the app.go file:

     // 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 
    ) 
     
    } 
    }