MySQL UPDATE statement using a table created on the fly

Question

I want to update a table, say Table 1 using a table that I create on the fly (saytemp). To achieve this I have the following query:

UPDATE Table1 SET COUNT = temp.ctemp FROM ( SELECT A, SUM(UNO) AS ctemp FROM Table1
                                            GROUP BY A 
                                            ORDER BY A) 
                                      AS temp,Table1 t1
                                      WHERE temp.A = t1.A;

It works well in SQL Server 2008 but MySQL throws out the error

syntax error, unexpected FROM, expecting 'END_OF_INPUT' or ';'

Any idea what I am missing here?