Proposal: Add `list` module to std for Array/List operations
As modern OLAP engines (such as DuckDB, ClickHouse, BigQuery, and PostgreSQL) increasingly support complex data types like Arrays and Lists, there is a growing need for a standardized way to handle these types in PRQL.
Currently, PRQL has a dedicated text module for string manipulations. I propose introducing a list (or array) module to provide a consistent and intuitive API for common list operations, such as checking for the existence of elements.
I suggest adding a list module to the standard library with the following functions. These functions will allow users to perform membership tests on arrays easily.
| function | parameters | description |
|---|---|---|
| has | value arr |
Returns true if arr contains value |
| has_any | values arr |
Returns true if arr contains any value from values |
| has_all | values arr |
Returns true if arr contains all values from values |
from employees
derive {
has_title = ([title, "CEO"] | list.has title),
has_any_role = ([title, country] | list.has_any [country, "CEO"]),
}I am happy to work on the implementation and the necessary compiler mappings for various dialects if the community agrees with this direction. What do you think?
Source: PRQL/prql