select p.FirstName as FirstName, p.LastName as LastName, a.City as City, a.State as State from Person as p left join Address as a on p.PersonId = a.PersonId;
問題:前面的高性能是如何做到的
select p.FirstName as FirstName, p.LastName as LastName, a.City as City, a.State as State from Person as p left join Address as a on p.PersonId = a.PersonId;
問題:前面的高性能是如何做到的