[dba-SQLServer] Formatting Numbers IN SQL

> There doesn't seem to be an SQL equivalent to the Access 
> Format(12345,"#,##0").  What is the simplest way of taking a number 
> like 12345.00 and converting it to a varchar "12,345"?

====First, is it 12345 or 12345.00? Or, could it be either? 

Susan H.