HasValue is equivalent to what?

[ResearchDev]

I am trying to convert the below code to a PowerBI Paginated report. What is the best way? If Has value in (:Sample Date) then perform a DateDiff function using Days to count from the difference between 2 days of which one is the data enter during a parameter the user selected date

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if hasvalue ({?Sample Date}) then
DateDiff("d",ITIdtToDate({T_SMPL.SMPL_DT}),{?Sample Date})
else
DateDiff("d",ITIdtToDate({T_SMPL.SMPL_DT}),{@currentdate})

[ResearchDev]

I use a query instead. Now when using the query in SQL developer it runs fine and show the number of days between but in report builder. I get a CAST Problem is the one in BOLD. 

SELECT
T_SMPL.SMPL_ID,
T_SMPL.SMPL_MIX_ID,
T_SMPL.SMPL_DT,
TO_DATE(SMPL_DT,'YYYYMMDD') smpl_dt_disp,
CASE WHEN
T_SMPL.SMPL_DT IS NULL OR T_SMPL.SMPL_DT=0 THEN SYSDATE
ELSE TO_DATE(T_SMPL.SMPL_DT,'YYYYMMDD') END - sysdate Days_Between,
T_PCC.MIX_ID
FROM
SM_ADMIN.T_SMPL T_SMPL
INNER JOIN SM_ADMIN.T_PCC T_PCC ON T_SMPL.SMPL_MIX_ID = T_PCC.MIX_ID

[amitchandak · Accepted solution]

@ResearchDev , if are looking for power bi, then we have hasonevalue https://p3adaptive.com/2013/03/hasonevalue-vs-isfiltered-vs-hasonefilter/