Postgres view column getter with casting for migrating views to functions and maintaining legacy

view_column_getter.sql

WITH 
    my_table_name AS 
    (
        SELECT 'v_forecast_summary' AS table_name
    )
,   colpad AS 
    (
        SELECT 
            MAX(length(columns.column_name)) AS pad
        FROM information_schema.columns 
        WHERE columns.table_name LIKE (SELECT table_name FROM my_table_name)
    )
,   datatypepad AS 
    (
        SELECT MAX(length(columns.data_type || COALESCE('(' || columns.character_maximum_length || ')',''))) AS pad
        FROM information_schema.columns 
        WHERE columns.table_name LIKE (SELECT table_name FROM my_table_name)
    )

SELECT '    ' || (SELECT table_name FROM my_table_name) || '.' || 
    STRING_AGG
    (
        rpad
        (
            columns.column_name
        ,   (
                SELECT pad FROM colpad
            )
        ,   ' '
        ) || ' ::' || RPAD(columns.data_type || COALESCE('(' || columns.character_maximum_length || ')',''),(SELECT pad FROM datatypepad)) || ' AS ' || columns.column_name

    ,   E'\n,   ' || (SELECT table_name FROM my_table_name) || '.' ORDER BY columns.ordinal_position 
    ) AS column_names
FROM information_schema.columns
WHERE columns.table_name = (SELECT table_name FROM my_table_name);