I would do it something like this:

Declare @Component smallint = -1

Select

sc.Comment As Comment,

t.NameFull As CommentType,

sc.parenttypeId As Component,

dt.periodQuarter,

dt.periodYear

From

srcComment sc

inner JOIN dimPeriod p

ON srcComment.ParentId = p.periodId

Left Outer Join refType t

ON t.TypeId = srcComment.ParentTypeId

outer apply (select Quarter, Year from dimPeriod dp where dp.periodId = sc.ParentId)dt(periodQuarter, periodYear)

where

(@Component = -1 and sc.parenttypeId IN (601, 605, 606)) or

(sc.parenttypeId = @Component);