Thank you Barbara you answer is correct i forget put >= and <= in the message,
the problem is not the filter o condition, the problem is that in the data base remote the table have not records duplicates ( 1000 records) , but the cursor obteined with the sqlprep and sqlxec, have records duplicates but not always the same.
I execute the same program several times and the result is not always the same.
Note, the data base remote is not changed never, but the cursor obtained from programm never is equal ( it's unbelivable but true , i am not crazy but i am near to be.)
Any idea?