sp_who vs sp

When deciding whether to use sp_who or sp_who2, check the table below for a detailed comparison list.

sp_who is documented and officially supported.
sp_who2 is undocumented and therefore unsupported but commonly used.

As you can see on the comparison table below, they both basically return the same information but sp_who2 includes some extra columns:

sp_who		sp_who2
spid	System process id	SPID	System process id
ecid	Execution context of the thread associated with the SPID. Zero means the main thread, all other numbers mean sub-threads.
status	Runnable, sleeping, or background. If the status is runnable that means the process is actually performing work, sleeping means the process is connected to the server, but is idle at the moment.	Status	Runnable, sleeping, or background. If the status is runnable that means the process is actually performing work, sleeping means the process is connected to the server, but is idle at the moment.
loginame	The login name of a user	Login	The login name of the user
hostname	Computer name of the user.	HostName	Computer name of the user.
blk	The SPID of the connection that is blocking the current connection	BlkBy	The SPID of the connection that is blocking the current connection
dbname	The database name where process is running	DBName	The database name where process is running
cmd	General command type currently being executed	Command	General command type currently being executed
		CPUTime	The number of milliseconds the request has used
		DiskIO	Disk input / output that the command has used
		LastBatch	Date and time of the last batch executed by the connection
		ProgramName	The name of the application that connected with
		SPID	Same SPID repeated at the end of the file for right-scrolling users