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Snowflake ARRAY_APPEND

   January 9, 2024
Snowflake

In this article, we will dive deep into the Snowflake ARRAY_APPEND function, exploring its capabilities, syntax, and practical use cases.

What is Snowflake ARRAY_APPEND?

The Snowflake ARRAY_APPEND function is a powerful SQL function designed for working with arrays in Snowflake data warehouses. It allows you to add one or more elements to the end of an existing array, making it a valuable tool for data manipulation and analysis.

Syntax

The syntax for the Snowflake ARRAY_APPEND function is straightforward:

ARRAY_APPEND(array_expression, value_to_append [, value_to_append, ...])
  • array_expression: This is the array to which you want to append values.
  • value_to_append: One or more values that you want to add to the end of the array.

Now, let’s explore some real-world examples to understand how ARRAY_APPEND works.

Real-World Example: Managing Employee Data

Suppose you have a table called freshers_employees with columns employee_id and department. Here’s how you can create the table and insert some sample data:

CREATE TABLE freshers_employees (
  employee_id INT,
  department VARCHAR(50)
);

INSERT INTO freshers_employees (employee_id, department)
VALUES
  (1, 'Sales'),
  (2, 'Marketing'),
  (3, 'Sales'),
  (4, 'HR'),
  (5, 'Marketing'),
  (1, 'BusinessDevelopment'),
  (2, 'Advertisement'),
  (3, 'BusinessDevelopment');

Now, let’s say you want to maintain a list of projects each employee is working on using an array. You can achieve this using ARRAY_APPEND.

-- Create an empty array column for projects
ALTER TABLE freshers_employees ADD projects ARRAY;

-- Append project names to the respective employees
UPDATE freshers_employees
SET projects = ARRAY_APPEND(projects, 'Project A')
WHERE employee_id = 1;

UPDATE freshers_employees
SET projects = ARRAY_APPEND(projects, 'Project B')
WHERE employee_id = 2;

-- Check the updated data
SELECT * FROM freshers_employees;

Output

EMPLOYEE_ID	DEPARTMENT	PROJECTS
3	Sales	[]
4	HR	[]
5	Marketing	[]
1	Sales	[  "Project A"]
1	BusinessDevelopment	[  "Project A"]
2	Marketing	[  "Project B"]
2	Advetisment	[  "Project B"]
3	BusinessDevelopment	[]

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