Oracle Wm_concat Stitching garbled display question marks, etc.

Today with Plsql query tool splicing SQL query display garbled, do not know why.

Later through the multi-find information is now shared as follows.

For the Oracle stitching function garbled, first query the Oracle character encoding is supported in Chinese, query statements:
SELECT * from nls_database_parameters WHERE PARAMETER = ' nls_characterset ';
If it is in Chinese, choose another way:
Wmsys.wm_concat (To_char (...)). should be added To_char ()
In the stitching field plus the conversion is possible.

Before query

After query

Oracle Wm_concat Stitching garbled display question marks, etc.