Question

I have a very fat common table expression which includes row numbers so that I can return a paged result set. I also want to return the total number of records that match the query before I page the result set.

with recs as (select *, row_number() over (order by id) as rownum from ......)
select * from recs where rownum between @a and @b .... select count(*) from recs

Obviously my query above is patchy, but it’s just for illustrating my point. I want a page of results AND the total number of matches. How do I do this without having to literally copy and paste the entire 20+ line CTE?

Answer 1

You can use commas to create multiple CTEs that references the CTEs Above.

Just to illustrate what I mean:

with recs as (
select 
    *, 
    row_number() over (order by id) as rownum from ......
    ),
counts as (
    select count(*) as totalrows from recs
)
select recs.*,count.totalrows
from recs
cross apply counts 
where rownum between @a and @b .... 

This is not the a good solution.

The best solution I found to have the total count in a CTE without counting the records is described in this article.

DECLARE @startRow INT; SET @startrow = 50;
WITH cols
AS
(
    SELECT table_name, column_name, 
        ROW_NUMBER() OVER(ORDER BY table_name, column_name) AS seq, 
        ROW_NUMBER() OVER(ORDER BY table_name DESC, column_name desc) AS totrows
    FROM [INFORMATION_SCHEMA].columns
)
SELECT table_name, column_name, totrows + seq -1 as TotRows
FROM cols
WHERE seq BETWEEN @startRow AND @startRow + 49
ORDERBY seq