select * from VWMaterialPriceList where
(CASE @model WHEN '0000' THEN true ELSE SUBSTRING( ClassCode,0*4+7,4) END) = @model
and (CASE @color WHEN '0000' THEN true ELSE SUBSTRING( ClassCode,1*4+7,4) END) = @color
(CASE @model WHEN '0000' THEN true ELSE SUBSTRING( ClassCode,0*4+7,4) END) = @model
and (CASE @color WHEN '0000' THEN true ELSE SUBSTRING( ClassCode,1*4+7,4) END) = @color
*
from
VWMaterialPriceList
where
SUBSTRING( ClassCode,0*4+7,4) = (CASE @model WHEN '0000' THEN SUBSTRING( ClassCode,0*4+7,4) else @model END)
and
SUBSTRING( ClassCode,1*4+7,4) = (CASE @color WHEN '0000' THEN SUBSTRING( ClassCode,1*4+7,4) ELSE @color END)