Transform a data set using SQL. Use the __THIS__
placeholder as a proxy for the active table.
ft_sql_transformer(x, input_col = NULL, output_col = NULL, sql)An object (usually a spark_tbl) coercable to a Spark DataFrame.
The name of the input column(s).
The name of the output column.
A SQL statement.
See http://spark.apache.org/docs/latest/ml-features.html for more information on the set of transformations available for DataFrame columns in Spark.
Other feature transformation routines: ft_binarizer,
ft_bucketizer,
ft_discrete_cosine_transform,
ft_elementwise_product,
ft_index_to_string,
ft_one_hot_encoder,
ft_quantile_discretizer,
ft_string_indexer,
ft_vector_assembler,
sdf_mutate