"SELECT hdiqtest_question.RecID FROM hdiqtest_question
WHERE convert(varchar,hdiqtest_question.RecID) NOT IN (SELECT convert(varchar,hdiqtest_records.QuestionID) FROM hdiqtest_records WHERE UserName='keen')";

RecID是hdiqtest_question里的字段
QuestionID,UserName是hdiqtest_records里的字段，原意是把hdiqtest_records里UserName=keen且QuestionID=RecID出现的记录不要
每次出现You have an error in your SQL syntax near 'varchar,hdiqtest_question.RecID) NOT IN (SELECT convert(varchar,hdiqtest_records'
请指教