Para SQL Server 2005 e abaixo:
CONVERT(varchar(8), @ParamDate, 112) -- Supported way
CAST(FLOOR(CAST(@ParamDate AS float)) AS DATETIME) -- Unsupported way
Para SQL Server 2008 e superior:
CAST(@ParamDate AS DATE)
CONVERT(varchar(8), @ParamDate, 112) -- Supported way
CAST(FLOOR(CAST(@ParamDate AS float)) AS DATETIME) -- Unsupported way
CAST(@ParamDate AS DATE)