public void updateweeks(string getdate)
{
    string result = getdate.Substring(0,10);
    OracleConnection con;
    OracleCommand cmd;
    con = new OracleConnection(strConnectionString);
    cmd = con.CreateCommand();
    cmd.CommandText = "UPDATE MO_T_WEEK_REPORT SET C_ISactIVE ='N' where TO_CHAR(TO_DATE(C_DATE,'DD/MM/YY hh24:mi:ss'),'DD/MM/YY')=TO_CHAR(TO_DATE('"+result+"','DD/MM/YY');";
    con.Open();
    cmd.ExecuteNonQuery();
    con.Close();                                          
} 

在上面的代码中引发“ ORA-00933：SQL命令未正确结束”的异常。