Oracle for Chinese conditional query because of different character set, empty query result

Oracle data query using C # for SQL or ASP. When the query condition exists in Chinese , because the data server and client/natively have different character sets , the data table has data, but the data is not queried. However, data queries can be made using the same string as the Oracle tool. Search terms Chinese to '??? Appear

SELECT   Sql_text, last_load_time from    v$sql   WHERE last_load_time isn't nullorder by Last_load_time DESC
The statement is viewed by the Oracle execution SQL statement.
Solution: Add unicode=true after c#sql connection to the database string

Oracle for Chinese conditional query because of different character set, empty query result