Sorry for my late response..

1. I fixed the problem because I missed the most out open and close brackets

2. I managed to make the structure you suggested work OK

 

 I found if I put anohter pair of parameters in the reports for dates, the report will prompt to ask you to enter  date even when I opt to use break_Type only;

By the way, am I able to integrate date range, e.g. start date and end date into the break type?

the following is the where clause structure in the SQL command that works, I wish to integrate date (start date, end date):

 

WHERE  (('{?break_type}' = 'CD' and LDTE = DATEADD(day, DATEDIFF(day, 0, GETDATE()), 0))
OR
  ('{?break_type}' = 'CW' and LDTE BETWEEN dateadd(week, datediff(week, 0, (getdate())), 0) AND dateadd(week, datediff(week, 0, (getdate())), 6))
OR
  ('{?break_type}' = 'CM' and LDTE BETWEEN DATEADD(month, datediff(month, 0, (getdate())), 0) AND  convert(datetime, convert(varchar(10), getdate(), 101)))
OR
 ('{?break_type}'='CQ' and LDTE BETWEEN DATEADD(qq, DATEDIFF(qq,0,getdate()), 0) AND  dateadd(dd,-1,dateadd(qq,1,DATEADD(qq, DATEDIFF(qq,0,getdate()), 0))))
OR
('{?break_type}'='CY' and LDTE BETWEEN DATEADD(yy, DATEDIFF(yy,0,getdate()), 0) AND  DATEADD(year, DATEDIFF(year, -1, getdate()), -1))
OR
('{?break_type}'='CFY' and LDTE BETWEEN  cast('01-Jul-' + cast( case when datepart(mm,getdate()) in (7,8,9,10,11,12) then DATEPART(yy,getdate())
             else DATEPART(yy,getdate())-1
               end as varchar) as datetime) AND                       
                              cast('30-Jun-' + cast( case when datepart(mm,getdate()) in (6,7,8,9,10,11,12) then DATEPART(yy,getdate())
                else DATEPART(yy,getdate())+1
               end as varchar) as datetime))
OR
('{?break_type}'='PD' and LDTE = DATEADD(day, DATEDIFF(day, 0, GETDATE()), -1))
OR
('{?break_type}'='PW' and LDTE between DATEADD(wk,DATEDIFF(wk,7,GETDATE()),0) and DATEADD(wk,DATEDIFF(wk,7,GETDATE()),6))
OR
('{?break_type}'='PM' and  LDTE between DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) - 1, 0) and
 DATEADD(DAY, -(DAY(GETDATE())), GETDATE()))
OR
('{?break_type}'='PQ' and LDTE between dateadd(quarter,datediff(quarter,0,getdate())-1,0) and DateAdd(day, -1, dateadd(qq, DateDiff(qq, 0, GETDATE()), 0)))
OR
('{?break_type}'='PFY' and LDTE  BETWEEN  cast('01-Jul-' + cast( case when datepart(mm,getdate()) in (7,8,9,10,11,12) then DATEPART(yy,getdate())
             else DATEPART(yy,getdate())-2
               end as varchar) as datetime) AND                       
                              cast('30-Jun-' + cast( case when datepart(mm,getdate()) in (6,7,8,9,10,11,12) then DATEPART(yy,getdate())
                else DATEPART(yy,getdate())-1
               end as varchar) as datetime))
OR
('{?break_type}'='PY' and LDTE between DATEADD(yy,-1,DATEADD(yy,DATEDIFF(yy,0,GETDATE()),0)) and DATEADD(ms,-3,DATEADD(yy,0,DATEADD(yy,DATEDIFF(yy,0,GETDATE()),0))))) ....