Teradata query pagination - batch every 1000 records - sql

Question

I've this Teradata query:
WITH ID(ROW_NUM) AS
(
SELECT ROW_NUMBER() OVER (ORDER BY PRSN_ID) AS ROW_NUM
FROM MyTable
WHERE ACTIVE_IND = 'Y'
GROUP BY PRSN_ID
)
SELECT ROW_NUM-ROW_NUM MOD 2 AS FirstIndex,
ROW_NUM-(ROW_NUM-1) MOD 2 AS SecondIndex
FROM ID
WHERE ROW_NUM MOD 2=1
This query will generate an ID column, and the result will be something like this:
FirstIndex SecondIndex
0 1
2 3
4 5
. .
. .
etc etc
I would like to change the selection to be a batch through a 1000 records like below:
FirstIndex SecondIndex
0 1000
1001 2000
2001 3000
3001 4000
. .
. .
etc etc
Your help is appreciated.

Answer 1

Your calculation is way to complex:
ROW_NUM-1 AS FirstIndex,
ROW_NUM AS SecondIndex
To get your requested range you simply need to modify the calculation, e.g.
SELECT
CASE WHEN ROW_NUM = 1 THEN 0 ELSE SecondIndex-999 END AS FirstIndex,
(ROW_NUM+2)/2 * 1000 AS SecondIndex
FROM ID
WHERE ROW_NUM MOD 2=1
But what do you want to do with that result, batch what?
Edit:
It's still unclear why you need a 2nd table to calculate the ranges, but this creates ranges starting from 1 for any pagesize of n rows:
WITH ID(ROW_NUM) AS
( -- just to get some rows
SELECT day_of_calendar AS row_num
FROM sys_calendar.CALENDAR
WHERE row_num BETWEEN 1 AND 10
)
SELECT 1000 AS RowsPerPage,
Row_Num AS page_num,
rownum_to - (RowsPerPage-1) AS rownum_from,
page_num * RowsPerPage AS rownum_to
FROM ID
GROUP BY page_num
ORDER BY page_num
RowsPerPage page_num rownum_from rownum_to
1000 1 1 1000
1000 2 1001 2000
1000 3 2001 3000
1000 4 3001 4000
1000 5 4001 5000
1000 6 5001 6000
1000 7 6001 7000
1000 8 7001 8000
1000 9 8001 9000
1000 10 9001 10000

Answer 2

Hi you can try the below query once, this will give you the desired sequence.
select ROW_NUM,FirstIndex, coalesce(case when SecondIndex<1000 then (SecondIndex+2000) else (SecondIndex+1000) end,FirstIndex+1001) as SecondIndex from
(SELECT ROW_NUM,
case when (FirstIndex < 1000) then (FirstIndex+1001) else (FirstIndex+1) end as FirstIndex,
(min(FirstIndex) OVER(ORDER BY FirstIndex ROWS BETWEEN 1 FOLLOWING AND 1 FOLLOWING)) SecondIndex
FROM (Select (ROW_NUMBER() OVER (ORDER BY PRSN_ID)-1) AS ROW_NUM,(ROW_NUMBER() OVER (ORDER BY PRSN_ID)-1) AS FirstIndex from Mytable GROUP BY PRSN_ID) A) B
order by ROW_NUM;