子查询问题?高手请进

[javame_sukeen]

"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

[ffyd2000]

"SELECT hdiqtest_question.RecID FROM hdiqtest_question
WHERE hdiqtest_question.RecID NOT IN (SELECT hdiqtest_records.QuestionID FROM hdiqtest_records WHERE UserName='keen')";
就这样不行么？

[helloyou0]

是mysql吗？
mysql里convert是转换编码用的
数字转字符是concat或cast

http://dev.mysql.com/doc/mysql/en/string-comparison-functions.html