SQL Stored Procedure If -Else Condition

how to determine if week one payroll exist base upon the data below. In the data below there are two pay periods week 1 and week 2. I am trying to wrap a stored procedure to say if week 1 pay exist then do something, then if pay period 2 exists do something. 

 

I need to determine if payroll weeks exist by date time and not ID. As you can see in the data below there are two 1 payroll period with 2 paypoll weeks. I can only calculate payoll week 2 only if week 1 payroll exist. So basically i need to know if 2015/7/21 - 2015/7/30 Payroll Week Exist before I can execute payroll week 2 2015/8/1 - 2015/8/4 

 

ID        EmpNum        Hours        PayType        StartDate        EndDate

 Stored Procedure Below:

 

if pay period 1 exist execute procedure below 

SELECT 

   EmpNum       

,SUM(CASE WHEN PayType = 'REG' THEN Hours ELSE 0 END) Hours       

,SUM(CASE WHEN PayType <> 'REG' THEN Hours ELSE 0 END) PTO     

  ,MIN(StartDate) StartDate       

,MAX(EndDate)  EndDate   

INTO #TempTable     

FROM @Tmp GROUP BY EmpNum

Then if pay period 2 exist execute another 

     Select   (80  - (Hours + PTO) ) AdjustHours From #TempTable

Else

 do nothing