loop thru db tables, check if particular column exists, then update the existing column

declare @tables Table(
id int identity(1,1),
name varchar(200)
)
insert into @tables(name)
SELECT name FROM sysobjects WHERE type = 'U'
declare @sql_string nvarchar(4000)
declare @name varchar(200), @min int, @max int
select @min=1
select @max=MAX(id) from @tables
while(@min <= @max)
begin
select @name = name from @tables where id = @min
if (exists(select * from information_schema.columns where table_name = @name and (column_name='editBy')) and
exists(select * from information_schema.columns where table_name = @name and (column_name='editDate')))
begin
set @sql_string = 'Update ' + @name + ' SET editBy=''engine upgrade'', editDate=getdate()'
--print @name
exec sp_executesql @sql_string
end
set @min = @min + 1
end