Need to Pick Max Date when status = N otherwise No in MYSQL - mysql

Question

I have a table which have records like this
ID DATEADD STATUS
'A0011' '04/01/2018 11:58:31' 'C'
'A0011' '31/05/2019 10:02:36' 'N'
'B0022' '04/01/2018 11:58:31' 'N'
'B0022' '31/05/2019 10:02:36' 'N'
'B0022' '30/04/2020 19:44:36' 'C'
'C0033' '04/01/2018 11:58:31' 'N'
'C0033' '30/05/2019 06:02:36' 'C'
'C0033' '29/04/2020 05:44:36' 'C'
I'm trying to get the Max Date for each ID which have STATUS = 'N'. If I get MAX DATE and STATUS = 'C' then I don't want that record.
Output :
ID DATEADD STATUS
'A0011' '31/05/2019 10:02:36' 'N'
SCRIPT :
SELECT I.* FROM INVOICE I
INNER JOIN (
Select ID,MAX(DATEADD)DATEADD,STATUS FROM INVOICE WHERE STATUS = 'N'
GROUP BY ID,STATUS) O
ON I.ID = O.ID AND O.DATEADD = I.DATEADD
But I'm not able to get desired output.

Answer 1

If your mysql version support the window function, we can try to use ROW_NUMBER window function to get each ID latest DATEADD then compare the STATUS
SELECT *
FROM (
SELECT *,ROW_NUMBER() OVER(PARTITION BY ID ORDER BY DATEADD DESC) rn
FROM INVOICE
) t1
WHERE rn = 1 AND STATUS = 'N'
sqlfiddle
if your MySQL version didn't support the window function we can try to use correlated subquery
SELECT *
FROM (
SELECT *, (SELECT COUNT(*)
FROM INVOICE tt
WHERE tt.ID = t1.ID AND tt.DATEADD > t1.DATEADD) rn
FROM INVOICE t1
) t1
WHERE rn = 1 AND STATUS = 'N'
sqlfiddle

Answer 2

You can use NOT EXISTS:
SELECT i1.*
FROM INVOICE i1
WHERE i1.STATUS = 'N'
AND NOT EXISTS (
SELECT 1
FROM INVOICE i2
WHERE i2.ID = i1.ID
AND STR_TO_DATE(i2.DATEADD, '%d/%m/%Y %H:%i:%s') > STR_TO_DATE(i1.DATEADD, '%d/%m/%Y %H:%i:%s')
);
If the column's DATEADD data type is DATETIME or TIMESTAMP the last condition would be simpler:
...AND i2.DATEADD > i1.DATEADD
See the demo.

Answer 3

We can use ORDER BY and LIMIT 1 to get the row that we want without using any functions, sub-queries, CTE etc.
Thank you to D-Shih for the test schema.
If we want the maximum date with status 'N' for each ID we can use the second query.
SELECT
ID,
DATEADD,
STATUS
FROM INVOICE
ORDER BY
STATUS DESC,
DATEADD DESC
LIMIT 1;
ID | DATEADD | STATUS
:---- | :--------- | :-----
A0011 | 2019-05-31 | N
SELECT
ID,
MAX(DATEADD) AS DATEADD,
STATUS
FROM INVOICE
WHERE STATUS = 'N'
GROUP BY ID
ORDER BY ID;
ID | DATEADD | STATUS
:---- | :--------- | :-----
A0011 | 2019-05-31 | N
B0022 | 2019-05-31 | N
C0033 | 2018-01-04 | N
db<>fiddle here