I have the same problem with a database that stores the date as a string, and then in the format of YYYY-MM-DD. I use this formula to reformat it (still as a string, date calcs won't work) but puts it into MM-DD-YYYY.
({Query.ActionDate}[6 to 7] + "-" + {Query.ActionDate}[9 to 10]+ "-" +
{Query.ActionDate}[1 to 4])