>I am trying to create a cursor by using an sql statement. One of my fields is a function. It sends four dates as parameters to the function. The function analizes the dates to find the lateest date. I need to return this value back to the cursor as a value for this field. Right now I get data mismatch. Please help.

If this is not run via SPT, why not just use the MAX() function?

SELECT MAX(date1, date2, date3, date4) AS MaxDate,...;
  FROM tablealias...;