(PHP 4 >= 4.0.5, PHP 5)
odbc_errormsg — Get the last error message
Returns a string containing the last ODBC error message, or an empty string if there has been no errors.
ODBC 连接标识符，详见 odbc_connect()。
If connection_id is specified, the last state of that connection is returned, else the last state of any connection is returned.
This function returns meaningful value only if last odbc query failed (i.e. odbc_exec() returned FALSE).