How to optimized Multiple CASE statement

Database

How to optimized Multiple CASE statement

Hi..

I am new to Teradata and really confused with the working of Case statement in Teradata.

Somebody please help me out to use most optimized Multiple CASE statement in below example.. 

Select

CAST(COUNT(DISTINCT(CASE WHEN period_id <350 THEN period_id END)) AS DECIMAL(30,0))  AS Column1,                                  

CAST(COUNT(DISTINCT(CASE WHEN period_id >=351 AND period_id<=375 THEN period_id END)) AS DECIMAL(30,0)) AS Column2,                                

CAST(COUNT(DISTINCT(CASE WHEN period_id >=376 AND period_id<=400 THEN period_id END)) AS DECIMAL(30,0)) AS Column3,                             

CAST(COUNT(DISTINCT(CASE WHEN period_id >=401 AND period_id<=450 THEN period_id END)) AS DECIMAL(30,0)) AS Column4,                             

CAST(COUNT(DISTINCT(CASE WHEN period_id >=451 AND period_id<=575 THEN period_id END)) AS DECIMAL(30,0)) AS Column5,

CAST(COUNT(DISTINCT(CASE WHEN pmc ='UVS' THEN pmc END)) AS DECIMAL(30,0)) AS Column6,                                

CAST(COUNT(DISTINCT(CASE WHEN pmc ='VAL' THEN pmc END)) AS DECIMAL(30,0)) AS Column7                            

FROM [Table1]

Thanks in Advance,

Deepak