原文 : [https://ask.csdn.net/questions/716991]
为什么pymysql（0.9.2）调用存储过程，获取输出参数有时没有？？？
操作系统：ubuntu16.4，
python:3.6版，
pymysql:0.9.2，
mysql:5.7.23版本，
程序代码为：

CREATE DEFINER=`root`@`%` PROCEDURE `P_TEST`(OUT aCode varchar(4), OUT aMsg 
    varchar(16), IN aAppName varchar(16))
COMMENT '测试'
BEGIN
    set aCode = '1';
    set aMsg = '错误信息';
    select aAppName;
END

python代码是：

def executeProc(aProcName, aParams):
tmpDbConn = None
tmpCursor = None
try:
    tmpListData = list(aParams)
    tmpListData.insert(0, '')
    tmpListData.insert(0, '')
    aParams = tuple(tmpListData)
    print(aProcName, aParams)

    tmpDbConn = DBPools.connection()
    tmpCursor = DBPools.connection().cursor()
    tmpCursor.callproc(aProcName, aParams)
    tmpDatas1 = tmpCursor.fetchall()
    print(tmpDatas1)
    tmpCursor.execute('select @_%s_0, @_%s_1 ;' % (aProcName, aProcName))
    tmpDatas2 = tmpCursor.fetchall()
    print(tmpDatas2)
    code = tmpDatas2[0][0]
    msg = tmpDatas2[0][1]
    tmpCursor.close()
    tmpDbConn.close()
    return (code, msg, tmpDatas1)
except InternalError as e:
    print(e)
    return (sqlServerInternalError, all_code[sqlServerInternalError])
except ProgrammingError as e:
    print(e)
    return (sqlServerProgrammingError, all_code[sqlServerProgrammingError])
except InterfaceError as e:
    print(e)
    return (sqlServerConnectFail, all_code[sqlServerConnectFail])
except OperationalError as e:
    print(e)
    return (sqlServerInterfaceError, all_code[sqlServerInterfaceError])
except Exception as e:
    print(e)
    return (sqlServerException, all_code[sqlServerException])
finally:
    if tmpCursor:
        tmpCursor.close()
    if tmpDbConn:
        tmpDbConn.close()

if __name__ == "__main__":
    for i in range(100):
        executeProc('P_TEST', ('a'))

试验结果为：

P_TEST ('', '', 'a')
(('a',),)
(('1', '错误信息'),)
P_TEST ('', '', 'a')
(('a',),)
((None, None),)
P_TEST ('', '', 'a')
(('a',),)
((None, None),)
P_TEST ('', '', 'a')
(('a',),)
(('1', '错误信息'),)
P_TEST ('', '', 'a')
(('a',),)
(('1', '错误信息'),)

这只是随机发生的。