full or complete database backup

execute master.dbo.xp_backup_database
  @database = '<database name>',
  @filename = '<path>\<backup file name>.bak',
  @init = 1,
  @compressionlevel = 4

differential backup

 
 execute master.dbo.xp_backup_database
  @database = '<database name>',
  @filename = '<path>\<backup file name>.bak',
  @init = 1,
  @compressionlevel = 4,
  @with =  differential

transaction log backup

 
 execute master.dbo.xp_backup_log
  @database = '<database name>',
  @filename = '<path>\<backup file name>.trn',
  @init = 1,
  @compressionlevel = 4

filegroup backup

   
 execute master.dbo.xp_backup_database 
  @database = '<database name>',
  @filename = '<path>\<backup file name>.bck',
  @init = 1,
  @compressionlevel = 4,
  @filegroup = 'filegroupname'