# How to Use ENUM_FIRST() Function in PostgreSQL

> The ENUM_FIRST() is a built-in function in Postgres that retrieves the first value of the enum specified by the parameter.

PostgreSQL supports a custom data type known as “ENUM” that is used to define a fixed set of values for the table's column. Enums provide a secure and reliable way of controlling what data can be inserted into a table's column. PostgreSQL offers various built-in functions that help us manipulate the Enums data efficiently.

This post will illustrate the working of the ENUM_FIRST() function using practical examples.

 **How to Use ENUM_FIRST() Function in PostgreSQL?**

The **ENUM_FIRST()** is a built-in function in Postgres that retrieves the first value of the enum specified by the parameter. Use the below-provided syntax to apply the ENUM_FIRST() function on the enum type:
    
    
    ENUM_FIRST(enum_value ENUM);

Here, enum_val is a mandatory parameter that represents an enumeration value.

 **Example: Using ENUM_FIRST() in Postgres**

First, let’s create an enum type named “example_enum” using the below-provided statement:
    
    
    CREATE TYPE example_enum AS ENUM (
    'Jan',
    'Feb',
    'Mar',
    'Apr',
    'May',
    'Jun',
    'Jul',
    'Aug',
    'Sep',
    'Oct',
    'Nov',
    'Dec'
    );

In the above code snippet, we utilized the CREATE TYPE to create an enum type that contains month names of the year:

Now, we will invoke the ENUM_FIRST on the example_enum to get the first enum value of “example_enum”:
    
    
    SELECT ENUM_FIRST(null::example_enum);

The output shows that the ENUM_FIRST() successfully retrieves the first enum value of the example_enum:

In the following code snippet, we will pass all enumeration values ​​of type example_enum to the ENUM_FIRST() function. As a result, the stated function will retrieve the following output:
    
    
    SELECT ENUM_FIRST('Jan'::example_enum),
    ENUM_FIRST('Feb'::example_enum),
    ENUM_FIRST('Mar'::example_enum),
    ENUM_FIRST('Apr'::example_enum),
    ENUM_FIRST('May'::example_enum),
    ENUM_FIRST('Jun'::example_enum),
    ENUM_FIRST('Jul'::example_enum),
    ENUM_FIRST('Aug'::example_enum),
    ENUM_FIRST('Sep'::example_enum),
    ENUM_FIRST('Oct'::example_enum),
    ENUM_FIRST('Nov'::example_enum),
    ENUM_FIRST('Dec'::example_enum);

The output shows that the ENUM_FIRST() function retrieves the first enumeration value:

This is how the ENUM_FIRST() function works in Postgres.

 **Conclusion**

The **ENUM_FIRST()** is a built-in function in Postgres that retrieves the first value of the enum specified by the parameter. It accepts a mandatory parameter “enum_val” that represents an enumeration value and retrieves the first value of the selected enum. This blog post demonstrated the use of the ENUM_FIRST() function in PostgreSQL using suitable examples.

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