Sybase: HAVING operates on rows?

Question

I\'ve came across the following SYBASE SQL:

-- Setup first
create table #t (id int, ts int)
go

insert into #t values (1, 2)
insert into #t values (1, 10)
insert         


        

Answer 1

I haven't done Sybase since it shared code with MS SQL Server....90's, but my interpretation of what you are doing is this:

First, the list is filtered to <= 11

id   ts
1    2
1    10
2    5

Everything else is filtered out.

Next, you are filtering the list to the rows where TS = the Max(TS) for that group.

id   ts
1    10
2    5

10 is the Max(TS) for group 1 and 5 is the Max(TS) for group 2. Those two rows are the ones that remain. What result would you expect otherwise?