You are currently looking at a table that contains data from an e-commerce platform, each row contains a list of items(Item number) that were present in the cart, when the customer makes a change to the cart the entire information is saved as a separate list and appended to an existing list for the duration of the customer session, to identify all the items customer bought you have to make a unique list of items, you were asked to create a unique item’s list that was added to the cart by the user, fill in the blanks of below query by choosing the appropriate higher-order function?

You are currently looking at a table that contains data from an e-commerce platform, each row contains a list of items(Item number) that were present in the cart, when the customer makes a change to the cart the entire information is saved as a separate list and appended to an existing list for the duration of the customer session, to identify all the items customer bought you have to make a unique list of items, you were asked to create a unique item’s list that was added to the cart by the user, fill in the blanks of below query by choosing the appropriate higher-order function?

Note: See below sample data and expected output.

Schema: cartId INT, items Array<INT>

Fill in the blanks:

Fill in the blanks:

SELECT cartId, _(_(items)) FROM carts
A . ARRAY_UNION, ARRAY_DISCINT
B . ARRAY_DISTINCT, ARRAY_UNION
C . ARRAY_DISTINCT, FLATTEN
D . FLATTEN, ARRAY_DISTINCT
E . ARRAY_DISTINCT, ARRAY_FLATTEN

Answer: C

Explanation:

FLATTEN -> Transforms an array of arrays into a single array.

ARRAY_DISTINCT -> The function returns an array of the same type as the input argument where all duplicate values have been removed.