sql系统中的存储过程，从中可以找到查询各种信息的语句

create procedure sys.sp_help
 @objname nvarchar(776) = NULL  -- object name we're after
as
 -- PRELIMINARY
 set nocount on
 declare @dbname sysname
  ,@no varchar(35), @yes varchar(35), @none varchar(35)
 select @no = 'no', @yes = 'yes', @none = 'none'  

 -- If no @objname given, give a little info about all objects.
 if @objname is null  ----传入空值
 begin
  -- DISPLAY ALL SYSOBJECTS --
        select
            'Name'          = o.name,
            'Owner'         = user_name(ObjectProperty( object_id, 'ownerid')),
            'Object_type'   = substring(v.name,5,31)
        from sys.all_objects o, master.dbo.spt_values v
        where o.type = substring(v.name,1,2) collate database_default and v.type = 'O9T'
        order by [Owner] asc, Object_type desc, Name asc  

  print ' '  

  -- DISPLAY ALL USER TYPES
  select
   'User_type' = name,
   'Storage_type' = type_name(system_type_id),
   'Length'  = max_length,
   'Prec'  = Convert(int,TypePropertyEx(user_type_id, 'precision')),
   'Scale'  = Convert(int,TypePropertyEx(user_type_id, 'scale')),
   'Nullable'  = case when is_nullable = 1 then @yes else @no end,
   'Default_name' = isnull(object_name(default_object_id), @none),
   'Rule_name'  = isnull(object_name(rule_object_id), @none),
   'Collation'  = collation_name
  from sys.types
  where user_type_id > 256
  order by name  

  return(0)
 end  

 -- Make sure the @objname is local to the current database.
 select @dbname = parsename(@objname,3)
 if @dbname is null
  select @dbname = db_name()
 else if @dbname <> db_name()
  begin
   raiserror(15250,-1,-1)
   return(1)
  end  

 -- @objname must be either sysobjects or systypes: first look in sysobjects
 declare @objid int
 declare @sysobj_type char(2)
 select @objid = object_id, @sysobj_type = type from sys.all_objects where object_id = object_id(@objname)  

 -- IF NOT IN SYSOBJECTS, TRY SYSTYPES --
 if @objid is null
 begin
  -- UNDONE: SHOULD CHECK FOR AND DISALLOW MULTI-PART NAME
  select @objid = type_id(@objname)  

  -- IF NOT IN SYSTYPES, GIVE UP
  if @objid is null
  begin
   raiserror(15009,-1,-1,@objname,@dbname)
   return(1)
  end  

  -- DATA TYPE HELP (prec/scale only valid for numerics)
  select
   'Type_name' = name,
   'Storage_type' = type_name(system_type_id),
   'Length'  = max_length,
   'Prec'   = Convert(int,TypePropertyEx(user_type_id, 'precision')),
   'Scale'   = Convert(int,TypePropertyEx(user_type_id, 'scale')),
   'Nullable'   = case when is_nullable=1 then @yes else @no end,
   'Default_name' = isnull(object_name(default_object_id), @none),
   'Rule_name'  = isnull(object_name(rule_object_id), @none),
   'Collation'  = collation_name
  from sys.types
  where user_type_id = @objid  

  return(0)
 end  

 -- FOUND IT IN SYSOBJECT, SO GIVE OBJECT INFO
 select
  'Name'    = o.name,
  'Owner'    = user_name(ObjectProperty( object_id, 'ownerid')),
        'Type'              = substring(v.name,5,31),
  'Created_datetime' = o.create_date
 from sys.all_objects o, master.dbo.spt_values v
 where o.object_id = @objid and o.type = substring(v.name,1,2) collate database_default and v.type = 'O9T'  

 print ' '  

 -- DISPLAY COLUMN IF TABLE / VIEW
 if exists (select * from sys.all_columns where object_id = @objid)
 begin  

  -- SET UP NUMERIC TYPES: THESE WILL HAVE NON-BLANK PREC/SCALE
  declare @numtypes nvarchar(80)
  select @numtypes = N'tinyint,smallint,decimal,int,real,money,float,numeric,smallmoney'  

  -- INFO FOR EACH COLUMN
  print ' '
  select
   'Column_name'   = name,
   'Type'     = type_name(user_type_id),
   'Computed'    = case when ColumnProperty(object_id, name, 'IsComputed') = 0 then @no else @yes end,
   'Length'     = convert(int, max_length),
   'Prec'     = case when charindex(type_name(system_type_id), @numtypes) > 0
          then convert(char(5),ColumnProperty(object_id, name, 'precision'))
          else '     ' end,
   'Scale'     = case when charindex(type_name(system_type_id), @numtypes) > 0
          then convert(char(5),OdbcScale(system_type_id,scale))
          else '     ' end,
   'Nullable'    = case when is_nullable = 0 then @no else @yes end,
   'TrimTrailingBlanks' = case ColumnProperty(object_id, name, 'UsesAnsiTrim')
          when 1 then @no
          when 0 then @yes
          else '(n/a)' end,
   'FixedLenNullInSource' = case
      when type_name(system_type_id) not in ('varbinary','varchar','binary','char')
       then '(n/a)'
      when is_nullable = 0 then @no else @yes end,
   'Collation'  = collation_name
  from sys.all_columns where object_id = @objid  

  -- IDENTITY COLUMN?
  if @sysobj_type in ('S ','U ','V ','TF') and @objid > 0
  begin
   print ' '
   declare @colname sysname
   select @colname = col_name(@objid, column_id) from sys.identity_columns where object_id = @objid
   select
    'Identity'    = isnull(@colname,'No identity column defined.'),
    'Seed'    = ident_seed(@objname),
    'Increment'   = ident_incr(@objname),
    'Not For Replication' = ColumnProperty(@objid, @colname, 'IsIDNotForRepl')
   -- ROWGUIDCOL?
   print ' '
   select @colname = null
   select @colname = name from sys.columns where object_id = @objid and is_rowguidcol = 1
   select 'RowGuidCol' = isnull(@colname,'No rowguidcol column defined.')
  end
 end  

 -- DISPLAY ANY PARAMS
 if exists (select * from sys.all_parameters where object_id = @objid)
 begin
  -- INFO ON PROC PARAMS  --查询存储过程参数--object_id=object_id(@TableName)
  print ' '
  select
   'Parameter_name' = name,
   'Type'   = type_name(user_type_id),
   'Length'   = max_length,
   'Prec'   = case when type_name(system_type_id) = 'uniqueidentifier' then precision
        else OdbcPrec(system_type_id, max_length, precision) end,
   'Scale'   = OdbcScale(system_type_id, scale),
   'Param_order'  = parameter_id,
   'Collation'   = convert(sysname, case when system_type_id in (35, 99, 167, 175, 231, 239)
      then ServerProperty('collation') end)  

  from sys.all_parameters where object_id = @objid
 end  

 -- DISPLAY TABLE INDEXES & CONSTRAINTS
 if @sysobj_type in ('S ','U ')
 begin
  print ' '
  EXEC sys.sp_objectfilegroup @objid
  print ' '
  EXEC sys.sp_helpindex @objname
  print ' '
  EXEC sys.sp_helpconstraint @objname,'nomsg'
  if (select count(*) from sysdepends where depid = @objid and deptype = 1) = 0
  begin
   raiserror(15647,-1,-1,@objname) -- No views with schemabinding reference table '%ls'.
  end
  else
  begin
            select distinct 'Table is referenced by views' = obj.name from sys.objects obj, sysdepends deps
    where obj.type ='V' and obj.object_id = deps.id and deps.depid = @objid
     and deps.deptype = 1 group by obj.name  

  end
 end
 else if @sysobj_type in ('V ') and @objid > 0
 begin
  -- VIEWS DONT HAVE CONSTRAINTS, BUT PRINT THESE MESSAGES BECAUSE 6.5 DID
  print ' '
  raiserror(15469,-1,-1,@objname) -- No constraints defined
  print ' '
  raiserror(15470,-1,-1,@objname) -- No foreign keys reference table '%ls'.
  EXEC sys.sp_helpindex @objname
 end  

 return (0) -- sp_help  

sp_help null