Use of the distinct to avoid the same value repeated (duplicate) records in the full rows,

And try this

select distinct

isnull(d.[name],'Unknown')as depot_name

,isnull(d.,'Unknown') as depot_code

, d.[status]

,cast(floor(cast(d.[last_date] as float)) as smalldatetime)as last_date

FROM [dbo].[Depot] d

WHERE d.status = 'L'