Select records with two Date columns in SQL Server

I have Two Dates

Declare @Date1 DateTime

Set @Date1='2015-01-18'

Declare @Date2 DateTime

Set @Date2='2020-04-23'

I have a table of slab to get rate (what was rate on what period)

FeeSlabId   Amount    SDate                                 EDate

1               500          2011-01-01 00:00:00.000    2019-12-31 00:00:00.000

2              550          2020-01-01 00:00:00.000    2020-12-31 00:00:00.000

Now I need to write SQL, result will show the both rows for the above declared dates.

Secondly, if the declared dates are like below the result will show on row only.

Declare @Date1 DateTime

Set @Date1='2015-01-18'

Declare @Date2 DateTime

Set @Date2='2019-04-23'