If a rental property is sold without depreciation taken in the past, can it be correct as "0"  for the prior year depreciation amount?  Under this senario, it seems no ordinary earned income with the return. Only capital gain tax related to this rental sale. 

However, if enter a data for the prior year depreciation amount based on depreciation table, the tax will be included two parts:1.) capital gain amount.  2.) ordinary earned income, which equals taxable income (line 15 1040) -Gapital gain amount (line 8 1040) 

It seems if no depreciation taken in the past, at the year when rental is sold, will result less tax due to no ordinary earned income.