selecting specific fields in rails 3.0.1 by using find_by_id method

i would like to select specific field with alias names by method find_by_id , like using the following query

Model.find_by_id(params) # I am getting  all the table columns, 
                         # but i would开发者_运维技巧 like to have only some columns
                         # with alias names.

can you please help me to achieve this?

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Model.select('column_name as alias').find_by_id(params)

Unless I am misunderstanding your question.