# How to Concatenate Multiple Arrays in PostgreSQL

> PostgreSQL provides a built-in function named ARRAY_CAT() and a concatenation operator “||” that assists us in concatenating multiple arrays into a single arra…

As a database developer or data analyst, you may face a situation where you have to combine/merge multiple arrays into a single array. This can be challenging, especially when handling large data sets or working with arrays with different data types. So, how to tackle such scenarios?

Thankfully, PostgreSQL provides a built-in function named **ARRAY_CAT()** and a concatenation operator “ **||** ” that assists us in concatenating/combining multiple arrays into a single array.

This blog post will show you how to concatenate multiple arrays into one array using the concatenation operator and the **ARRAY_CAT()** function. So, let’s get started!

 **How to Concatenate Multiple Arrays in Postgres Via ARRAY_CAT()?**

The **ARRAY_CAT()** function accepts different arrays as arguments and retrieves a concatenated array. Whether you are working with alphabetic, numeric, or a combination of both, the **ARRAY_CAT()** function can assist you in each case. Use the following syntax to avail the functionality of the **ARRAY_CAT()** function:
    
    
    ARRAY_CAT(arr_1, arr_2, arr_3, … arr_N);

The **ARRAY_CAT()** function accepts an “n” number of arrays and combines them into one array.

 **Example: How to Concat Multiple Arrays Via ARRAY_CAT() in Postgres?**

We have already created a sample table named “staff_information”, whose data is shown in the following snippet:

Let’s concatenate the “ **st_name** ” and “ **st_email** ” arrays via the **ARRAY_CAT()** function:
    
    
    SELECT ARRAY_CAT(st_name, st_email) 
    FROM staff_information;

The output snippet shows that the targeted arrays have been combined successfully.

 **How to Concatenate Multiple Arrays in Postgres Via Concatenation Operator?**

You can also use the concatenation operator between different arrays to combine them into a single array. The below snippet shows the usage of the concatenation operator:
    
    
    SELECT array_3 || array_2 || … || array_n;

The above syntax shows that the “ **n** ” number of arrays can be combined using the concatenation operator.

 **Example: How to Concat Multiple Arrays Via Concatenation Operator in Postgres?**

In the following example, we will show you how to merge multiple arrays using the concatenation operator in Postgres:
    
    
    SELECT st_name || st_email AS merged_array
    FROM staff_information;

The above piece of code will combine the “ **st_name** ” and “ **st_email** ” arrays of the “ **staff_inforamation** ” table:

The output snippet shows that both columns have been concatenated successfully.

This way, you can concatenate two or more arrays in Postgres.

 **Conclusion**

PostgreSQL provides a built-in function named ARRAY_CAT() and a concatenation operator “||” that assists us in concatenating/combining multiple arrays into a single array efficiently. The ARRAY_CAT() function and the concatenation operator accept the “n” number of arrays and combine them into a single array. Through practical examples, this blog post explained how to concatenate multiple arrays into one array using the concatenation operator and the **ARRAY_CAT()** function.

---
[View this page online](https://www.commandprompt.com/education/how-to-concatenate-multiple-arrays-in-postgresql/)