SQL combinnig columns

Heyaa SQL-wizards. How do i combine two columns into one? Firstname and Lastname -columns need to be combined as Name -column. Databases previous user fucked up with tableformats and this table contains more than 900 names....

Create the Name column and run:

MySQL: UPDATE YourTable SET Name = CONCAT( Firstname, ' ', Lastname )
Oracle: UPDATE YourTable SET Name = Firstname || ' ' || Lastname
MSSQL: UPDATE YourTable SET Name = Firstname + ' ' + Lastname

etc