start date and end date in one report line using a calculated field

[vanderLeest]

Following syntax worked as script for a calculated field in a previous report:

label: Time Period (Start Date)
[@field:EA_StartDate] +
CASE
WHEN LEN([@field:EA_EndDate]) > 1 THEN
' - ' + [@field:EA_EndDate]
END

Currently [@field:EA_StartDate] + ' - ' already generates "Invalid Formula" when verifying the script.

[vanderLeest]

This cumbersome syntax is a Valid Formula:

DatePart(mm,[@field:EA_StartDate]) + '-' + DatePart(dd,[@field:EA_StartDate]) + '-' + DatePart(yy,[@field:EA_StartDate]) +

CASE 
WHEN LEN([@field:EA_EndDate]) > 1 THEN
 ' - ' + DatePart(mm,[@field:EA_EndDate]) + '-' + DatePart(dd,[@field:EA_EndDate]) + '-' + DatePart(yy,[@field:EA_EndDate]) 
END

NB Substituting '-' with '/' (for a more standard date display) results in an Invalid Formula