Select only the row with the max value, but the column with this info is a SUM() - sql

Question

I have the following query:
SELECT DISTINCT
CAB.CODPARC,
PAR.RAZAOSOCIAL,
BAI.NOMEBAI,
SUM(VLRNOTA) AS AMOUNT
FROM TGFCAB CAB, TGFPAR PAR, TSIBAI BAI
WHERE CAB.CODPARC = PAR.CODPARC
AND PAR.CODBAI = BAI.CODBAI
AND CAB.TIPMOV = 'V'
AND STATUSNOTA = 'L'
AND PAR.CODCID = 5358
GROUP BY
CAB.CODPARC,
PAR.RAZAOSOCIAL,
BAI.NOMEBAI
Which the result is this. Company names and neighborhood hid for obvious reasons
The query at the moment, for those who don't understand Latin languages, is giving me clients, company name, company neighborhood, and the total value of movements.
in the WHERE clause it is only filtering sales movements of companies from an established city.
But if you notice in the Select statement, the column that is retuning the value that aggregates the total amount of value of sales is a SUM().
My goal is to return only the company that have the maximum value of this column, if its a tie, display both of em.
This is where i'm struggling, cause i can't seem to find a simple solution. I tried to use
WHERE AMOUNT = MAX(AMOUNT)
But as expected it didn't work

Answer 1

You tagged the question with the whole bunch of different databases; do you really use all of them?
Because, "PL/SQL" reads as "Oracle". If that's so, here's one option.
with temp as
-- this is your current query
(select columns,
sum(vrlnota) as amount
from ...
where ...
)
-- query that returns what you asked for
select *
from temp t
where t.amount = (select max(a.amount)
from temp a
);

Answer 2

You should be able to achieve the same without the need for a subquery using window over() function,
WITH T AS (
SELECT
CAB.CODPARC,
PAR.RAZAOSOCIAL,
BAI.NOMEBAI,
SUM(VLRNOTA) AS AMOUNT,
MAX(VLRNOTA) over() AS MAMOUNT
FROM TGFCAB CAB
JOIN TGFPAR PAR ON PAR.CODPARC = CAB.CODPARC
JOIN TSIBAI BAI ON BAI.CODBAI = PAR.CODBAI
WHERE CAB.TIPMOV = 'V'
AND STATUSNOTA = 'L'
AND PAR.CODCID = 5358
GROUP BY CAB.CODPARC, PAR.RAZAOSOCIAL, BAI.NOMEBAI
)
SELECT CODPARC, RAZAOSOCIAL, NOMEBAI, AMOUNT
FROM T
WHERE AMOUNT=MAMOUNT
Note it's usually (always) beneficial to join tables using clear explicit join syntax. This should be fine cross-platform between Oracle & SQL Server.