SUM postgres not like expected - postgresql

Question

after the query I would like to obtain the SUM of account_move_line.balance AS ammounteur
when account_id, partner_id, invoice_id and account_account.code were =
SELECT
account_move_line.name, account_move_line.account_id,
account_move_line.partner_id, account_move_line.invoice_id,
account_move_line.journal_id,
CASE
WHEN account_account.code LIKE '40%%'
THEN '400000'
WHEN account_account.code LIKE '44%%'
THEN '440000'
ELSE account_account.code
END AS ACCOUNTGL,
CASE
WHEN account_account.code = '702000'
THEN SUM(account_move_line.balance)
ELSE (round(account_move_line.balance, 2))
END AS AMOUNTEUR
FROM
public.account_move_line
JOIN
account_account ON (account_account.id = account_move_line.account_id)
WHERE
(account_move_line.date BETWEEN '2020-03-01' AND '2020-03-31')
GROUP BY
account_move_line.account_id, account_move_line.partner_id,
account_move_line.invoice_id, account_move_line.journal_id,
account_account.code, account_move_line.balance, account_move_line.name
ORDER BY
account_move_line.account_id, account_move_line.invoice_id;
The result I get:
NAME account_id Partner_id Invoice_id J_id accountgl amounteur
"Taxe led" 186 2476 1883 1 "702000" -0.83
"Taxe eclairage" 186 2476 1883 1 "702000" -0.11
"Taxe gros et petit blanc" 186 3090 1884 1 "702000" -0.83
"Taxe eclairage" 186 2077 1885 1 "702000" 0.25
"Taxe eclairage" 186 2077 1887 1 "702000" -0.25
"Taxe eclairage" 186 2077 1888 1 "702000" -0.02
"Taxe led" 186 2481 1916 1 "702000" -0.83
"Taxe eclairage" 186 2481 1916 1 "702000" -0.52
I expected
NAME account_id Partner_id Invoice_id J_id accountgl amounteur
186 2476 1883 1 "702000" -0.94
"Taxe gros et petit blanc" 186 3090 1884 1 "702000" -0.83
"Taxe eclairage" 186 2077 1885 1 "702000" 0.25
"Taxe eclairage" 186 2077 1887 1 "702000" -0.25
"Taxe eclairage" 186 2077 1888 1 "702000" -0.02
186 2481 1916 1 "702000" -1.35
Thanks

Answer 1

I'm guessing, but it seems you expect the results to be grouped by account_id, partner_id, invoice_id, and perhaps journal_id. But you've told it to group by so many more columns.
account_move_line.account_id,
account_move_line.partner_id,
account_move_line.invoice_id,
account_move_line.journal_id,
account_account.code,
account_move_line.balance,
account_move_line.name
To be grouped, a row would have to have the same account, partner, invoice, and journal IDs. Plus the same code, balance, and name.
Cut your group by back to just the four IDs.
This will mean you cannot select some columns because the group has several values for that column. For example, the name. Each group will contain several names, no single name can be selected.