Hi @S_Tran,
For an individual field you could replace each value expression by this type of expression:
if(empty(item()?['Order_x0020_Date']), 'NO DATA', item()?['Order_x0020_Date'])
With the expression below you could check if the whole HTML table is empty
length(outputs('Get_rows_(v2)')?['body/value'])
is equal to 0