Choose output value based on column values- use of 'IF' in 'SELECT' statement

SELECT id, 

       IF(type = 'P', amount, amount  -1) as amount

FROM report

SELECT id, 

       IF(type = 'P', IFNULL(amount,0), IFNULL(amount,0)  -1) as amount

FROM report

select id,

    case report.type

        when 'P' then amount

        when 'N' then -amount

    end as amount

from

    `report`

select 

  id,

  case 

    when report_type = 'P' 

    then amount 

    when report_type = 'N' 

    then -amount 

    else null 

  end

from table