pymssql 报20002错误解决办法：DB-Lib error message 20002, severity 9

python 版本：3.6  win32 版本（因为一些特殊原因必须使用3.6）

pymssql 版本：2.2.0  

连接数据库：

    import  pymssql
**
    def InitMssql(self):
        try:
            host = self.IniConfig.get('default','dbhost',"host***")
            user=  self.IniConfig.get('default','dbuser',"dbs***")
            password =  self.IniConfig.get('default','dbpassword',"pwd***")
            database =  self.IniConfig.get('default','dbdatabase',"db***")
            #self.DBconn = pymssql.connect(host,user,password,database,charset="GBK")
            self.DBconn = pymssql.connect(host,user,password,database)
            self.DBcursor = self.DBconn.cursor()
            sql = "SET TEXTSIZE 2147483647"
            self.DBcursor.execute(sql)
            self.DBconn.commit()
        except Exception as ex:
            if self.DBconn: self.DBconn.rollback()
            raise ex

报错信息如下：

2023-11-19 22:27:06,374 - (20002, b'DB-Lib error message 20002, severity 9:\n
Adaptive Server connection failed (www.***.com)\n
DB-Lib error message 20002, severity 9:\nAdaptive Server connection failed (www.***.com)\n')
Traceback (most recent call last):
  File "src\\pymssql\\_pymssql.pyx", line 647, in pymssql._pymssql.connect
  File "src\\pymssql\\_mssql.pyx", line 2109, in pymssql._mssql.connect
  File "src\\pymssql\\_mssql.pyx", line 701, in pymssql._mssql.MSSQLConnection.__init__
  File "src\\pymssql\\_mssql.pyx", line 1818, in pymssql._mssql.maybe_raise_MSSQLDatabaseException
  File "src\\pymssql\\_mssql.pyx", line 1835, in pymssql._mssql.raise_MSSQLDatabaseException
pymssql._mssql.MSSQLDatabaseException: (20002, b'DB-Lib error message 20002, severity 9:\n
Adaptive Server connection failed (www.*****.com)\n
DB-Lib error message 20002, severity 9:\n
Adaptive Server connection failed (www.*****.com)\n')

During handling of the above exception, another exception occurred:

尝试解决1：加charset参数，失败

在网上搜相关信息，发现信息量很少，偶尔提到的解决方案都是加 charset参数。

譬如：

1、DB-Lib error message 20002, severity 9 - chungehpu - 博客园 (cnblogs.com)  加连接参数 charset="CP936"

2、DB-Lib error message 20002, severity 9_pymssql._pymssql.operationalerror: (20002, b'db-li-CSDN博客 也是加连接参数 charset="CP936"

3、还有github上SQL Server database encoding (GBK) is not consistent with python · Issue #820 · pymssql/pymssql · GitHub 加连接参数 charset="GBK" 

尝试加连接参数，再次报同样的错误。

尝试解决2：切换到python3.4，成功。

切换到python3.4，不加charset写法，结果成功。

最终解决方案：python3.6，安装pymssql低版本（pymssql-2.1.5-cp36-cp36m-win32.whl），成功

到 Archived: Python Extension Packages for Windows - Christoph Gohlke (uci.edu) 找到pymssql 2.1.5 ，卸载原有的高版本，手工安装whl。

成功！