How to Read Data using SQL Query -OR- Execute Script (i.e. CREATE, SELECT, INSERT, UPDATE, DELETE) — Google BigQuery Connector for Tableau

Introduction

In this article we will delve deeper into Google BigQuery and Tableau integration, and will learn how to read data using sql query -or- execute script (i.e. create, select, insert, update, delete). We are continuing from where we left off. By this time, you must have created ODBC Data Source and connected to Google BigQuery. So, let's not waste time and begin.

Use Query Builder to generate SQL query

1. The first thing you have to do is open Query Builder:

   

   ZappySys API Driver - Google BigQuery

   Read / write Google BigQuery data inside your app without coding using easy to use high performance API Connector

   GoogleBigqueryDSN

   

2. Then simply select the Read Data using SQL Query -OR- Execute Script (i.e. CREATE, SELECT, INSERT, UPDATE, DELETE) endpoint (action).

3. Continue by configuring the Required parameters. You can also set optional parameters too.

4. Move on by hitting Preview Data button to preview the results.

5. If you see the results you need, simply copy the generated query:

   Read Data using SQL Query -OR- Execute Script (i.e. CREATE, SELECT, INSERT, UPDATE, DELETE)

   Required Parameters
   SQL Statement (i.e. SELECT / DROP / CREATE)	Select the value from the dropdown
   Optional Parameters
   Use Legacy SQL Syntax?	false
   timeout (Milliseconds)	90000
   Job Location

   SELECT * FROM get_query
   WITH
   (
       "Sql" = 'SELECT title,id,language,wp_namespace,reversion_id ,comment,num_characters FROM bigquery-public-data.samples.wikipedia LIMIT 1000'
   )

   

6. That's it! You can use this query in Tableau.

Let's not stop here and explore SQL query examples, including how to use them in Stored Procedures and Views (virtual tables) in the next steps.

SQL query examples

Use these SQL queries in your Tableau data source:

How to Read data using sql query -or- execute script

SELECT * FROM get_query
WITH
(
    "Sql" = 'SELECT title,id,language,wp_namespace,reversion_id ,comment,num_characters FROM bigquery-public-data.samples.wikipedia LIMIT 1000'
)

Stored Procedures and Views

Create Custom Stored Procedure

You can create procedures to encapsulate custom logic and then only pass handful parameters rather than long SQL to execute your API call.

Steps to create Custom Stored Procedure in ZappySys Driver. You can insert Placeholders anywhere inside Procedure Body. Read more about placeholders here

1. Go to Custom Objects Tab and Click on Add button and Select Add Procedure:
   

2. Enter the desired Procedure name and click on OK:
   

3. Select the created Stored Procedure and write the your desired stored procedure and Save it and it will create the custom stored procedure in the ZappySys Driver:
   Here is an example stored procedure for ZappySys Driver. You can insert Placeholders anywhere inside Procedure Body. Read more about placeholders here
   

   CREATE PROCEDURE [usp_get_orders]
       @fromdate = '<<yyyy-MM-dd,FUN_TODAY>>'
    AS
       SELECT * FROM Orders where OrderDate >= '<@fromdate>';
   

   
   

4. That's it now go to Preview Tab and Execute your Stored Procedure using Exec Command. In this example it will extract the orders from the date 1996-01-01:
   

   Exec usp_get_orders '1996-01-01';

   
   

5. Let's generate the SQL Server Query Code to make the API call using stored procedure. Go to Code Generator Tab, select language as SQL Server and click on Generate button the generate the code.
   As we already created the linked server for this Data Source, in that you just need to copy the Select Query and need to use the linked server name which we have apply on the place of [MY_API_SERVICE] placeholder.
   

   SELECT * FROM OPENQUERY([LS_TO_GOOGLE_BIGQUERY_IN_GATEWAY], 'EXEC usp_get_orders @fromdate=''1996-07-30''')

   
   

6. Now go to SQL served and execute that query and it will make the API call using stored procedure and provide you the response.
   

Create Custom Virtual Table

ZappySys API Drivers support flexible Query language so you can override Default Properties you configured on Data Source such as URL, Body. This way you don't have to create multiple Data Sources if you like to read data from multiple EndPoints. However not every application support supplying custom SQL to driver so you can only select Table from list returned from driver.

If you're dealing with Microsoft Access and need to import data from an SQL query, it's important to note that Access doesn't allow direct import of SQL queries. Instead, you can create custom objects (Virtual Tables) to handle the import process.

Many applications like MS Access, Informatica Designer wont give you option to specify custom SQL when you import Objects. In such case Virtual Table is very useful. You can create many Virtual Tables on the same Data Source (e.g. If you have 50 URLs with slight variations you can create virtual tables with just URL as Parameter setting.

1. Go to Custom Objects Tab and Click on Add button and Select Add Table:
   

2. Enter the desired Table name and click on OK:
   

3. And it will open the New Query Window Click on Cancel to close that window and go to Custom Objects Tab.

4. Select the created table, Select Text Type AS SQL and write the your desired SQL Query and Save it and it will create the custom table in the ZappySys Driver:
   Here is an example SQL query for ZappySys Driver. You can insert Placeholders also. Read more about placeholders here
   

   SELECT
     "ShipCountry",
     "OrderID",
     "CustomerID",
     "EmployeeID",
     "OrderDate",
     "RequiredDate",
     "ShippedDate",
     "ShipVia",
     "Freight",
     "ShipName",
     "ShipAddress",
     "ShipCity",
     "ShipRegion",
     "ShipPostalCode"
   FROM "Orders"
   Where "ShipCountry"='USA'

   
   

5. That's it now go to Preview Tab and Execute your custom virtual table query. In this example it will extract the orders for the USA Shipping Country only:
   

   SELECT * FROM "vt__usa_orders_only"

   
   

6. Let's generate the SQL Server Query Code to make the API call using stored procedure. Go to Code Generator Tab, select language as SQL Server and click on Generate button the generate the code.
   As we already created the linked server for this Data Source, in that you just need to copy the Select Query and need to use the linked server name which we have apply on the place of [MY_API_SERVICE] placeholder.
   

   SELECT * FROM OPENQUERY([LS_TO_GOOGLE_BIGQUERY_IN_GATEWAY], 'EXEC [usp_get_orders] ''1996-01-01''')

   
   

7. Now go to SQL served and execute that query and it will make the API call using stored procedure and provide you the response.
   

Read Data using SQL Query -OR- Execute Script (i.e. CREATE, SELECT, INSERT, UPDATE, DELETE) in Tableau

We are at the point where we can reiterate on how to use the SQL query, Stored Procedures or Views in Tableau:

1. Open Tableau Desktop and click File > New
2. To create new Connection click More > Microsoft SQL Server > Enter your credentials to connect to SQL Server (in our example before we used tdsuser):
3. Once connection is created for SQL Server we can read Google BigQuery data 3 different ways:
   1. Query View which contains OPENQUERY to Linked Server for Google BigQuery data
   2. Use direct SQL Query using OPENQUERY
   3. Use Stored Procedure (Mostly useful to parameterize calls
4. See below example to pull data from Google BigQuery in Tableau using SQL View approach:
5. Once your data sources are created you can click on Sheet1 and drag fields to create visualizations for Tableau Dashboard:

More integrations

Other application integration scenarios for Google BigQuery