# How to Use ABS() Function in PostgreSQL

> PostgreSQL offers a built-in mathematical function named ABS() that takes an expression as an argument and retrieves an absolute value for the specified number…

PostgreSQL offers a built-in mathematical function named **ABS()** that takes a number or expression as an argument and retrieves an absolute value of the specified number. The absolute value of a number indicates how far it is away from zero. It is a non-negative(always positive) value because it doesn’t signify the direction.

This post will explain the following topics through practical examples:

  * How to Use ABS() Function in Postgres?
  * What is the ABS() Function, and How Does it Work on Positive Values?
  * How Does the ABS() Function Work on Negative Values?
  * How Does the ABS() Function Work on Table’s Data?



So, let’s get started!

 **How to Use ABS() Function in Postgres?**

To use the Postgres ABS() function, follow the below syntax:
    
    
    ABS(numeric_expression);

The syntax illustrates the below-listed points:

  * The **ABS()** function accepts only one argument, i.e., a numeric expression.
  * The data type of the retrieved value depends on the data type of the value passed to the **ABS()** function.
  * In the case of negative numbers, the **ABS()** function will return the negation of that number.



Let’s implement it practically.

 **What is the ABS() Function and How Does it Work on Positive Values?**

Let’s pass a positive numeric value to the **ABS()** function and see how it works:
    
    
    SELECT ABS(1001.5225);

Since the passed value was non-negative, therefore the ABS() function retrieved that value as it is.

 **How Does the ABS() Function Work on Negative Values?**

In this example, we will pass a negative numeric value to the ABS() function:
    
    
    SELECT ABS(-1001.5225);

This time we passed a negative value to the ABS() function. Consequently, the ABS() function retrieved the negation of that number.

 **How Does the ABS() Function Work on Table’s Data?**

For profound understanding, we create a table named abs_example containing an original_val column. The original_val column will accept numeric values:
    
    
    CREATE TABLE abs_example(
    original_val NUMERIC
    );

Let’s insert some positive as well as negative values into the abs_example table:
    
    
    INSERT INTO abs_example(original_val)
    VALUES (550),
    (-210), 
    (72.12),
    (-87.93),
    (-0.0);

Let’s utilize the ABS() function on the abs_example table to see how the ABS() function works on the table’s data:
    
    
    SELECT original_val, ABS(original_val) AS absolute_value
    FROM abs_example;

The output verifies the working of the ABS() function.

 **Conclusion**

PostgreSQL provides an inbuilt mathematical function named **ABS()** to get an absolute value. It takes a number or expression as an argument and retrieves an absolute value of the specified number. The absolute numeric value represents how far it is away from zero. It is a non-negative(always positive) value because it doesn’t signify the direction. Through practical examples, this article explained the working of the ABS() function.

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