How to remove UCS-2 surrogate pairs in SQL Server?

遇到的问题：

Error during charset conversion of wstring: No error

解决方案：
第一步：找出UCS-2 surrogate pairs

SELECT * FROM chartest WHERE text LIKE NCHAR(0xdc83)

第二步：用NULL替换

UPDATE chartest SET text  = NULL WHERE text  = ''

参考文献：http://dba.stackexchange.com/questions/37343/sql-server-to-mysql-migration-how-can-i-remove-ucs-2-surrogate-pairs-in-sql-se