# How to Use in JSONB_ARRAY_LENGTH() Function in PostgreSQL

> In PostgreSQL, a built-in function named “JSONB_ARRAY_LENGTH()” is used to determine the length of a JSONB array.

PostgreSQL provides a **JSON** array data type that helps us store ordered collections in JSON format. While **JSONB** arrays store the data in “ **JSON Binary** ” format. In PostgreSQL, various built-in functions are used to deal with the JSON and JSONB data efficiently. One such function is **JSONB_ARRAY_LENGTH()** which retrieves the length of the given JSONB array.

This post illustrates a comprehensive guide to finding the length of the given JSONB array.

 **How to Use in JSONB_ARRAY_LENGTH() Function in PostgreSQL**

In Postgres, a built-in function named “ **JSONB_ARRAY_LENGTH()** ” is used to calculate/determine the length of a JSONB array. The retrieved length represents the total number of elements in that particular JSONB array.

 **Syntax**

Use the below-stated syntax to retrieve the length of a JSON array using the JSON_ARRAY_LENGTH() function:
    
    
    JSON_ARRAY_LENGTH(array JSON);

 **Parameters**

The stated function accepts a single argument “array” that represents a JSONB array.

 **Return Value**

The stated function retrieves the length of the given JSONB array.

 **Return Type**

It retrieves an **INTEGER** value which indicates the length of the specified JSONB array.

 **Example 1: Finding the Length of a JSONB Array in Postgres**

The below code snippet demonstrates the use of the JSONB_ARRAY_LENGTH() function in PostgreSQL:
    
    
    SELECT JSONB_ARRAY_LENGTH('["John", "Joseph", "Mike", ["Stephen", "Seth"]]');

The stated function retrieves the length of the specified array:

 **Example 2: Finding the Length of a JSONB Column in PostgreSQL**

Let’s set up a sample table with the following structure:
    
    
    CREATE TABLE emp_table_1 (
    emp_id SERIAL PRIMARY KEY,
    emp_data JSONB
    );

Now execute the following query to insert new records into the “emp_table”:
    
    
    INSERT INTO emp_table(emp_data) 
    VALUES
    ('[100, 120, 30, 210, 1]'),
    ('["John", "Joseph", "Mike", "Johnson", "Miller"]'),
    ('[{"e_name": "John", "e_age": 28},
    {"e_name": "Johnson", "e_age": 32},
    {"e_name": "Joseph", "e_age": 27}]')
    RETURNING *;

The desired records have been successfully inserted into the “emp_table”:

Now we will use the JSONB_ARRAY_LENGTH() function to find the length of the “emp_data” column:
    
    
    SELECT emp_data, 
    JSONB_ARRAY_LENGTH(emp_data)
    FROM emp_table;

The stated function successfully retrieves the length of the given JSONB array:

That’s all about finding the length of a JSONB array in PostgreSQL.

 **Conclusion**

In PostgreSQL, a built-in function named “ **JSONB_ARRAY_LENGTH()** ” is used to determine the length of a JSONB array. The retrieved length represents the total number of elements in that particular JSONB array. The stated function accepts a single argument “array” which must be a JSONB array. This post has illustrated the working of the JSONB_ARRAY_LENGTH() function in PostgreSQL.

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