sql modifying entries by adding a space

I just ran this command update table set mydata = '$' + mydata where [mydata] not like '$%' which w开发者_StackOverfloworked well, but I forgot to include the space.

so now I have $123 and $ 123 how can I add the space to all entries?

For SQL SERVER you can

Update
   table 
Set
   mydata = '$ ' + Right(mydata, Len(mydata)-1)
Where
   mydata Not Like '$ %'