CatBoost UDF

CatBoost::LoadModel(
  String -- path to file with the model
) -> Resource<CatBoost.TFormulaEvaluator> -- indicates a ready-to-use model

CatBoost::EvaluateBatch(
  Resource<Catboost.TFormulaEvaluator>, -- result CatBoost::LoadModel
  List<
    Struct<
      FloatFeatures:List<Float>, -- numerical features
      CatFeatures:List<String>, -- categorial features
      PassThrough:* -- arbitrary data passed through the function unchanged
    >
  >,
  Uint32? -- TargetCount, number of targets in the model. Default is 1
  Uint32? -- BatchSize, default is 128
) -> List<
  Struct<
    Result:List<Float>, -- model application result
    PassThrough:* -- passed to PassThrough argument unchanged
  >
> -- result

PRAGMA file( -- specify the URL where to get the model
    "model.bin",
    "<URL>"
);

-- Initialize CatBoost FormulaEvaluator with given model:
$evaluator = CatBoost::LoadModel(
    FilePath("model.bin")
);

-- Prepare the data:
$data = (SELECT
    [ -- Float features are packed into a List<Float>
        Age,
        Income,
        Float1,
        Float2,
        Float3,
        Float4
    ] AS FloatFeatures,
    [ -- Cat features are packed into List<String>
        Cat1,
        Cat2,
        Cat3,
        `Group`,
        Education,
        MaritalStatus,
        Occupation,
        Children,
        Nationality,
        Gender,
        `String`
    ] AS CatFeatures,
    Target AS PassThrough -- you can pass any values through
                          -- batch mode of CatBoost as is
FROM catboost_data);

$processed = (PROCESS $data
USING CatBoost::EvaluateBatch( -- Evaluate model in batch mode
    $evaluator,                -- on the data above
    TableRows()
));

SELECT
    Result[0] > 0.5 AS Guess, -- this model has one target,
                              -- so the Result list has only one item
    PassThrough == "1" AS Answer, -- the PassThrough contains the Target column
                                  -- value that has been passed to it
    Result[0] - 0.5 AS Score
FROM $processed;