如何使用红移获得第一行和最后一行？

Question

I have this table in redshift

no   date_status           date_ant          status   row_ant
1    11 Jan 2023, 07.00  11 Jan 2023, 07.00   ANT      1
1    11 Jan 2023, 09.00  11 Jan 2023, 10.00   AU       2
1    12 Jan 2023, 12.00  12 Jan 2023, 12.00   DLV      3
2    14 Jan 2023, 09.00  14 Jan 2023, 09.00   ANT      1
2    14 Jan 2023, 10.00  14 Jan 2023, 10.00   AU       2
2    15 Jan 2023, 10.00  15 Jan 2023, 14.00   ANT      3    

I want to write a query which supposed to get the first and last row based date_status and also row_ant for each no

I want to get the date_ant where the status = ANT and row_ant = 1 , while for the last row I want to get maximum date_status and the status column whatever the value is

The desired result would be something like this:

no         date_ant        first_status   date_last_status    last_status
1    11 Jan 2023, 07.00        ANT        12 Jan 2023, 12.00     DLV
2    14 Jan 2023, 09.00        ANT        15 Jan 2023, 10.00     ANT

how can I get the desired result above with a query in redshift? I supposed it can use row partition by, but I am not exactly sure how to get the correct table.

Any help would be much appreciated. Thank you in advance

Answer 1

We can use ROW_NUMBER() here, twice :

WITH cte AS (
    SELECT *, ROW_NUMBER() OVER (ORDER BY date_ant) rn1,
              ROW_NUMBER() OVER (ORDER BY date_ant DESC) rn2
    FROM yourTable
    WHERE status = 'ANT' AND row_ant = 1
)

SELECT no, date_status, date_ant, status, row_ant
FROM cte
WHERE rn1 = 1 OR rn2 = 1
ORDER BY date_status;