# How to Concatenate a String and a Number in PostgreSQL

> PostgreSQL allows us to concatenate a string with a number using a built-in “CONCAT()” function or a pipe concatenation operator “||”.

PostgreSQL allows us to concatenate a string with a number using a built-in “ **CONCAT()** ” function or a pipe operator **“||”**. Using these two approaches, we can add a separator, like a comma, space, etc., between a string and a number.

This blog post will show you how to concatenate a string with a number using the practical implementation of the **CONCAT()** function and pipe concatenation operator **“||”**.

 **Key Points**

Before learning how to concatenate a string and a number in Postgres, firstly, we need to understand the following points:

\- The return type of the pipe concatenation operator **||** and CONCAT() function is “ **TEXT** ”.  
\- Multiple strings can be concatenated using the **CONCAT()** function or the || operator.  
\- Using the **CONCAT()** function or the **||** operator, you can concatenate the strings with a number.  
\- In Postgres, you can’t concatenate only numeric values using the **CONCAT()** function or || operator. There must be at least one string. This is because the return type of both these approaches is **TEXT**.  
\- Concatenating a NULL value with a number or string will retrieve “ **NULL** ”.

 **Concatenating a String and a Number in Postgres Using CONCAT() Function**

To concatenate a string with a number, users must pass a string and a number to the CONCAT() function as arguments:
    
    
    CONCAT(arg_1, arg_2);

 **Example 1: How Do I Concatenate a String With a Number Using CONCAT() Function?**

Suppose we have a string “ **Postgres** ” and the number “ **14.4** ”. Suppose we want to concatenate the given string and the number. To do so, we will execute the **CONCAT()** function as follows:
    
    
    SELECT CONCAT('Postgres', 14.4);

The output authenticates the working of the CONCAT() function as it concatenates the given number and a string successfully.

 **Example 2: Concatenate a String and a Number With a Separator**

You can use a separator like space, comma, semicolon, etc., between the given string and number to present the concatenated result in a better way:
    
    
    SELECT CONCAT('Postgres', ':', 14.4);

The given number and string are concatenated using the ":" as a separator.

 **Example 3: Concatenate Table’s Column Using CONCAT() Function**

In our Postgres database, we have a table named “emp_info” that contains the following records:
    
    
    SELECT * FROM emp_info;

Let’s learn how to concatenate a numeric column with a string-type column using the CONCAT() function:
    
    
    SELECT CONCAT(emp_id, ',', emp_name)
    FROM emp_info;

The output shows that a numeric column has been successfully concatenated with a text-type column.

 **How to Concatenate a String and a Number in Postgres Using “||” Operator?**

To concatenate a string with a number, users must use the pipe concatenation operator between the input values as follows:
    
    
    SELECT arg_1 || arg_2;

You can append any separator between the input values using the || operator.

 **Example 1: Concatenate a Number With a String Using Pipe Concatenation Operator**

In this example, we will concatenate a string “PostgreSQL” and a number “14.4” using the **“||”** operator:
    
    
    SELECT 'PostgreSQL' || ' ' || 14.4;

The output proves that the input values have been concatenated successfully.

 **Example 2: Concatenate a Numeric Column With a String Type Column Using || Operator**

Let’s concatenate the “ **emp_id** ”, and “ **emp_name** ” columns of the “ **emp_info** ” table using the **||** operator:
    
    
    SELECT emp_id || '-' || emp_name
    FROM emp_info;

The output shows that both columns have been concatenated successfully.

 **Conclusion**

PostgreSQL allows us to concatenate a string with a number using a built-in “ **CONCAT()** ” function or a pipe operator **“||”**. The return type of the pipe concatenation operator || and CONCAT() function is “TEXT”. So, using these methods, you can concatenate multiple strings and numbers in Postgres. Through practical examples, this blog post explained how to concatenate a string with a number in Postgres.

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