Ecto.Query.API.any

You're seeing just the function any, go back to Ecto.Query.API module for more information.

Tests whether one or more values returned from the provided subquery match in a comparison operation.

from p in Product, where: p.id = any(
  from(li in LineItem, select: [li.product_id], where: li.created_at > ^since and li.qty >= 10)
)

A product matches in the above example if a line item was created since the provided date where the customer purchased at least 10 units.

Both any and all must be given a subquery as an argument, and they must be used on the right hand side of a comparison. Both can be used with every comparison operator: ==, !=, >, >=, <, <=.