Date Calculation is blank if one of the dates blank

[common763]

I am getting a "Expressions that yeild variant data-type cannot be used to define calculated columns" error" if I change the 0 to "".  I know this is simple but need help.  I have the below calculated column.  

Days btw dates = if(ISBLANK(DATE1,0, if(ISBLANK(DATE2),0,NETWORKDAYS(DATE1,DATE2)))

Right now it is displaying 0 if the DATE1 or DATE2 is blank.  I want it to display "" or nothing if one or both of the dates are missing.  Can someone help me tweak this calculated column to do so if one of the dates or both are blank?  

[common763]

My head wasnt working yesterday...all i had to do was this below...I was putting "" instead of Blank()

Days btw dates = if(ISBLANK(DATE1,0, if(ISBLANK(DATE2),0,NETWORKDAYS(DATE1,DATE2)))

to

Days btw dates = if(ISBLANK(DATE1,BLANK(), if(ISBLANK(DATE2),BLANK(),NETWORKDAYS(DATE1,DATE2)))

[common763]

thanks.  this works.  Appreciate it. 

[Dangar332 · Accepted solution]

Hi, @common763 

Try below measure

 Days btw dates=
if(
ISBLANK(DATE1),
0,
if(
ISBLANK(DATE2),
0,
NETWORKDAYS(DATE1,DATE2)))

OR 

Days btw dates =
 if(
   ISBLANK(DATE1),
   "",
   if(
     ISBLANK(DATE2),
     "",
     convert( NETWORKDAYS(DATE1,DATE2),STRING)
   )
 )