访问SQL返回每个给定字段的第n行

Question

My problem

Let's say I have a query that returns the following data:

id     date
--    ------
1     2015-01-12
1     ... // here I might have X more rows
1     2015-06-30
2     2015-01-12
2     ... // here I might have Y more rows
2     2015-05-20
...

Given that X, Y >= 120 and X != Y and the order of the query is id, date ASC I want a way to retrieve the record number 120 for id 1 and the 120 for the id 2 (and so on for each different ID), something like:

id      date
--    --------
1     2015-03-24 // this is the record 120 for id = 1
2     2015-04-26 // this is the record 120 for id = 2
...

Notice that the dates don't follow a sequential order (you may have a gap between one row and the next one).

Is there a direct SQL solution for my problem? (I know I can use vba to achieve my goal but I rather stay with SQL)

As a clarification note, see this example. Given the following resultset:

id     date
--    ------
1     2015-01-12  // this is record 1 for id = 1
1     2015-01-13  // this is record 2 for id = 1
1     2015-01-20  // this is record 3 for id = 1
1     2015-01-21  // this is record 4 for id = 1
...
1     2015-03-22  // this is record 118 for id = 1
1     2015-03-23  // this is record 119 for id = 1
1     2015-03-24  // this is record 120 for id = 1
1     2015-03-25  // this is record 121 for id = 1
...
1     2015-06-30  // this is the last row for id = 1
2     2015-01-12  // this is record 1 for id = 2
2     2015-01-13  // this is record 2 for id = 2
...
2     2015-04-25  // this is record 120 for id = 2
...
2     2015-05-20  // this is the last record for id = 2

The result should be:

id      date
--    --------
1     2015-03-24
2     2015-04-26

Remember, I have at least 120 records for each ID, this is a fact (I have a query that gives only the IDs with more than 119 records)

Attempted solution

I've tried to play with the SELECT TOP directive, but I fail to achieve the results I want as I cannot apply it direcly: I don't want the top 120 and then get the last row as I want the last one of the TOP 120 for each ID.

Edited for (a second) clarification

My goal would be to have something like:

SELECT id, 120thRow(date)
FROM table
GROUP BY id;

unfortunatelly I don't know how to implement the 120thRow function in access.

Answer 1

Does this work in Access?

select t.*
from table as t
where t.date = (select top 1 date
                from (select top 120 date
                      from table t2
                      where t2.id = t.id
                      order by date
                     ) as tt
                order by date desc
               );

EDIT:

I guess MS Access doesn't allow nesting in the correlation clause. You can do this more painfully as:

select t.*
from table as t join
     (select t.id, max(t.date) as maxdate
      from table as t
      where t.date = (select top 120 date
                      from table as t2
                      where t2.id = t.id
                      order by date
                     )
     ) tt
     on t.id = tt.id and t.date = tt.maxdate;

Answer 2

Sorry for my previous answer, I misunderstood you. I have another approach but in SQL. I am almost sure that it does not work in Access but might give you an idea.

-- start: this is just preparation of some sample data
declare @t table (id int, date datetime)
declare @id int, @d datetime, @c int
set @c = 0
set @id = 1
set @d = '2015-01-01'
while @c <= 125
    begin
    insert into @t values (@id, @d)
    set @d = dateadd(day, 1, @d)
    set @c = @c + 1
    end
set @c = 0
set @id = 2
set @d = '2015-01-02'
while @c <= 125
    begin
    insert into @t values (@id, @d)
    set @d = dateadd(day, 1, @d)
    set @c = @c + 1
    end
-- end: this is just preparation of some sample data

-- this is somewhat like what you need:
select id, date from 
(select id, date, row_number() over (partition by id order by date) as rc from @t) as mytable
where rc = 120

Answer 3

In the end, I've managed a way to put a row counter for each day and ID like so:

select id, date, 
       (
          select count(date) 
          from table As t1 
          where t1.id = t.id
            and t1.date <= t.date
       ) As rowNum
from table As t

From here on it's just a matter of selecting from this resultset the rows which has rownum = 120 and game over.

Answer 4

Hi I think this must work for you.

with Records AS
(select row_number() over(order by sort_column_name) as 'row', * 
       from table_name) select * from records where row=n

• sort_column_name – mention the name of the column which is sorting the table.
• n – row number
• table_name – mention the name of the table table name