SQL：如何获取下一个非空值

Question

SQL to get next not null value in column

I am trying to use this solution but I am totally new in SQL and could not understand

select t., t2.orig as newval 
from @t t 
outer apply (select top 1 t2. from @t t2 where t2.id >= t.id 
and t2.orig is not null order by t2.id ) t2;

What is t.*? Where Comes the value t2 and id, as I dont see it in the Question?

Answer 1

t2 is an alias. Where it's written

from @t t2

that is giving the alias of t2 to the table @t so it can be referenced by either. t2.id is just referencing the id column specifically from the instance of @t you've named t2. You need to reference it like this whenever you've joined with tables that have the same column name, because without it the code doesn't know from which table you're trying to make reference to.