Google BigQuery CONCAT: 4 Critical Aspects


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Today, there are a lot of Database software tools on the internet. Unfortunately, most of them are designed to process small-size data. 

If you try to analyze complex data on regular Database software, say Airtable, Microsoft Access, Oracle Database, and more, you might crash the system. These easy-to-use databases start to fail as the complexity increases. Also with complex data, the performance of queries drops significantly. 

This is where Google BigQuery comes in. The tool was designed specifically to handle Big Data Analysis. Amazingly, the Database software analyzes gigabytes and terabytes of data within minutes.

You’ve just started using Google BigQuery, and have been asked to combine numerous values into one result. Doing this manually will, no doubt, take you a lot of time, and you’ll probably end up with a few costly mistakes. The good news is you can automate the process and achieve your goal faster using the Google BigQuery CONCAT command. 

All you have to do is input your values under the Google BigQuery CONCAT command to combine them quickly. The BigQuery CONCAT command helps in the concatenation of two or more Strings into a single result.

This article will explore how to use the Google BigQuery CONCAT function as well as how to arrange your values. You will also get to read some real-life examples.

Table of Contents

Introduction to Google BigQuery

Google BigQuery logo
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Google BigQuery is a tool that creates real-time analytic reports of Big Data to help you generate useful insights. You can use these valuable insights to make effective business decisions for your organization. 

Meanwhile, you should avoid using Google BigQuery as a Relational Database. A Relational Database is one that stores related information in a table. 

What this means is that all the records in the same column in a Relational Database share a relationship, just as the records in the same row in the Database are related. 

Google BigQuery is not suitable to be used as a replacement for a Relational Database as it is a Data Warehouse solution. Imagine taking minutes to enter a 2-column table of 5 rows. 

Rather than using your Google BigQuery account as a Relational Database, you most likely want to use a more appropriate software like PostgreSQL as a Relational Database for your Big Data while using Google BigQuery to analyze the data. 

It is important to note that Google BigQuery works best with single tables. So, if the data you are trying to input is in multiple tables, it’s best to merge them into a single table before entering the query.

3 Primary Benefits of Google BigQuery

  • Google BigQuery gives you insights on how to improve your business process.
  • You can use Google BigQuery to share data with other members of your organization.
  • The platform also lets you protect your data with encryption.

For more information on Google BigQuery, click here.

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Google BigQuery CONCAT Command

Google BigQuery Concat Command image
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The CONCAT command enables you to merge values from different strings into one string. The input values you select under the CONCAT command must be BYTE or STRING data bytes. The CONCAT command is an important function when there is a requirement for combining multiple fields for storage. 

This is because your CONCAT command may return a ‘NULL’ if your input values are neither BYTE nor STRING values. Your CONCAT query will also produce a ‘NULL’ result if any of your input values are ‘NULL’.

4 Critical Aspects of BigQuery CONCAT

SQL Syntax in Google BigQuery CONCAT

SQL Syntax is a list of rules that determines the order of items in SQL programs such as Google BigQuery. Before you understand how syntax works in Google BigQuery CONCAT, you need to learn a few things about SQL syntax.

Basic SQL Syntax Rules

  • You can write syntax keywords, such as SELECT or UNION ALL, in uppercase or lowercase. However, using uppercase letters when writing keywords makes your query easier to read. 
  • SQL statements are read in the form of text lines. You cannot place two SQL statements on the same text lines. However, writing a single SQL statement over multiple text lines is allowed.

A typical SQL statement looks like this: SELECT “column_name”  FROM “table_name.” 

Notation Rules in Google BigQuery CONCAT

Notation rules refer to the usage of certain symbols in BigQuery. Following are the notation rules in Google BigQuery CONCAT:

  • Parenthesis (): Parenthesis is used to select a value from a table.
  • Square Brackets []: Square brackets are used to create strings.
  • [,…]: This means that a comma must separate the item in value1 from the next value in the computed result. 
  •  “ ”: This indicates that there must be a space between the items that precede and come after this symbol.
  • WITH: This function is used to indicate the table name for your input values.
  • SELECT: If you select more than one item in this operator, they will appear as a single value under one output column in the computed result.
  • SELECT * FROM: This operator returns the original amount of columns on the input table in the computed result.
  • UNION ALL: This operator combines values from two or more SELECT SQL Statements into a single result. 

Read on to see how these rules work in the following examples:

Grade Table

The table below shows a list of students with their grades in an examination.

First NameGrade

To enter this data into Google BigQuery, you must input the following commands:

Next, enter the Query: SELECT * FROM Grade to create a temporary table for analysis.

Google BigQuery CONCAT Command Syntax

This is how to input values under the CONCAT function: 

(value1 [,…] )

Remember that the operator ([,…] ) means that the value preceding it must be separated from the following values by a comma.

Usage of the CONCAT Command

Analysts use the Google BigQuery CONCAT command to merge large sets of values from different strings into a single string. For instance, administrative officers may need to combine the first and last names of successful job applicants into an employee database.

Example CONCAT Command Queries

  • Releases Table
November 2020
July 2021
February 2020
WITH Releases AS
(SELECT “November” AS month
“2020” AS year 
SELECT “July” AS month
“2021” AS year
SELECT “September” AS month
“2022” AS year
SELECT “August” AS month
“2020” AS year
SELECT “May” AS month
“2021” AS year
SELECT “February” AS month
“2020” AS year
SELECT “April” AS month
“2022” AS year)
 CONCAT(month, “  ”, year) 
AS release_date
FROM Releases


November 2020
July 2021
September 2022
August 2020
May 2021
February 2020
April 2022
  • New_Employees Table
First NameLast Name
WITH New_Employees AS
(SELECT “Adam” AS first_name
“Kweller” AS “last_name
SELECT “Calvin” AS first_name
“James” AS last_name
SELECT “Rose” AS first_name
“Nairobi” AS last_name
SELECT “Hassan” AS first_name
‘Kabir” AS last_name)
CONCAT( first_name, “  ”, last_name)
AS full_name


Adam Kweller
Calvin James
Rose Nairobi
Hassan Kabir

Frequently Asked Questions (FAQs)

How do you Concatenate BigQuery?

The Concatenation can be performed in BigQuery using the BigQuery CONCAT function or using the concatenation operator (“ || “). Both methods combine two or more BYTE into a single entity. BigQuery CONCAT String can combine STRING entities.

How do you Strip a String in BigQuery?

The trimming function can be used to remove specific characters from a string. This function offers a choice to remove a character from particular positions. Use the following syntax to use the Trimming function: TRIM(val1[,val2]). This helps in removing all leading and trailing char that match val2.  

How do I combine two datasets in BigQuery?

Combining datasets is a 4 step process. First, select the data from each table you want to connect. Second, Use SQL Joins to combine the data. Third, Connect the bigquery data to google studio. Finally, you can view the combined datasets on Data Studio. 

Does BigQuery support merge?

The BigQuery supports the merge operation and this can be done using MERGE Command. The MERGE command helps in updating, inserting, and deleting data from BigQuery tables. 


The article introduced you to Google BigQuery and to automate the process and achieve your goal faster using the Google BigQuery CONCAT command. It also provided the SQL syntax and notational rules for the Google BigQuery CONCAT command.

BigQuery has the provision to combine STRINGS and BYTES into a single format so that it becomes easier to perform operations, and also efficiently store the data. There are many functions in the BigQuery suite that improves its efficiency.

 Now that you have learned the basics of the CONCAT function, you are ready to start using the command for your data for faster data processing and improved decision-making. You can check out the Merge command from BigQuery which is effective in combining multiple datasets..

With the complexity involved in Manual Integration, businesses are leaning more towards Automated and Continous Integration. This is not only hassle-free but also easy to operate and does not require any technical proficiency. 

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Isola Saheed Ganiyu
Technical Content Writer, Hevo Data

Isola is a freelance writer specializing in the domains of data integration and data analysis. He has a passion towards creating engaging and educational content, breaking down these sophisticated subjects for easily understanding.

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