const char *
mysql_stmt_sqlstate(MYSQL_STMT *stmt)
          For the statement specified by stmt,
          mysql_stmt_sqlstate() returns
          a null-terminated string containing the SQLSTATE error code
          for the most recently invoked prepared statement API function
          that can succeed or fail. The error code consists of five
          characters. "00000" means “no
          error.” The values are specified by ANSI SQL and ODBC.
          For a list of possible values, see
          Error Messages and Common Problems.
        
          Not all MySQL errors are mapped to SQLSTATE codes. The value
          "HY000" (general error) is used for
          unmapped errors.
        
          If the failed statement API function was
          mysql_stmt_close(), do not
          call mysql_stmt_sqlstate() to
          obtain error information because
          mysql_stmt_close() makes the
          statement handler invalid. Call
          mysql_sqlstate() instead.