use MO

declare @i bigint = (select max(id) from [_Log_QueryMO] where DateStart<getdate()-7)
set @i = 51700681
set nocount on
set rowcount 100000
set deadlock_priority low
select 1
while @@rowcount>0 begin 
	waitfor delay '00:00:00.2'
	delete [_Log_QueryMO] where id<@i
end
go