sqlServer获取星期和时间段

select 
        convert(varchar(100),  getdate(), 25) as 当前时间,
        datename(weekday, convert(varchar(100),  getdate(), 11)) as 星期,
        case 
                when convert(varchar(100),  getdate(), 14) < '12:00:00.000' then '0-12点'
                when convert(varchar(100),  getdate(), 14) >= '18:00:00.000' then '18-0点'
                else '12-18点'
        end as '当前时间段'