ora-64203:Destination buffer too small to hold CLOB data after character set conversion.

拼接字符串时过长引起，报缓冲区太小错误

SELECT WM_CONCAT(field_A|| field_b)
FROM table_A
WHERE field_A= ADDRESS.field_A and rownum<10

加上条件限制，让拼接出来的字符串不超长就可以了。