MySql UNION for UPDATE

Is there a way to update multiple rows with different values for each row using a single SQL query? I have to update one colum in many rows with different data. Using individual update queries for each row seems excessive so if it's possible I would like to consolidate this process into a single SQL statement or at least reduce the number of queries required.

I am using PHP with the Zend framework and MySql.

From stackoverflow

• Create a temporary table and fill it with:

  CREATE TEMPORARY TABLE temptable (id INTEGER, VALUE VARCHAR(200))
  
  INSERT
  INTO temptable
  VALUES
    ('1', 'val1'),
    ('2', 'val2'),
    ('3', 'val3'),
    ('4', 'val4')
  

  Then issue:

  UPDATE
    mytable m, temptable t
  SET m.value = t.value
  WHERE m.id = t.id
  

• I know this works for SQL Server, so it's worth a try in MySQL.

  update xtable
  set a = 
     Case
       when a = "a"
       then z
       when a = "b"
       then y
     End
  where ...
  

  You can construct the case statement based on your different rows.

  : It works in MySql but, when you does not change the colum a on every entry the others will be set empty.

• Don't know about MySQL specifically, but to update multiple rows based on a SELECT, or a UNION of multiple SELECTs, I would do

  UPDATE U
  SET MyColumn = T.OtherColumn
  FROM MyUpdateTable AS U
       JOIN
       (
           SELECT [OtherColumn] = OtherColumn1
           FROM MyOtherTable1
           WHERE ...
           UNION
           SELECT OtherColumn2
           FROM MyOtherTable2
           WHERE ...
       ) AS T
           ON T.ID = U.ID