✨ DB Nerdery Challenges Solutions II #53
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README.md
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| @@ -60,7 +60,7 @@ create database nerdery_challenge; | |||
| ``` | |||
| \q | |||
| ``` | |||
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| C:\Users\arago\OneDrive\Escritorio\nerdery-repos\DB-Nerdery-Challenges\src\dump.sql | |||
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I was copying the dump.sql path and forgot to delete from readme file
README.md
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| SELECT type, SUM(mount) AS total | ||
| FROM accounts | ||
| group by type |
README.md
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| 2. How many users with at least 2 `CURRENT_ACCOUNT`. | ||
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| ```sql | ||
| SELECT count(u.name) as user_w_least_two_accounts |
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What it is going to happen if for any reason do you have a null value in u.name?
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This will only count u.name fields with values and ignore null fields
README.md
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| DO | ||
| $$ | ||
| DECLARE | ||
| account_balance RECORD; | ||
| BEGIN | ||
| FOR account_balance IN | ||
| WITH account_balances AS (SELECT u.name, | ||
| a.account_id, | ||
| a.mount AS initial_mount, | ||
| COALESCE(SUM( | ||
| CASE | ||
| WHEN m.type = 'TRANSFER' AND m.account_from = a.id | ||
| THEN -m.mount | ||
| WHEN m.type = 'TRANSFER' AND m.account_to = a.id | ||
| THEN m.mount | ||
| WHEN m.type = 'IN' AND m.account_from = a.id | ||
| THEN m.mount | ||
| WHEN m.type = 'OUT' AND m.account_from = a.id | ||
| THEN -m.mount | ||
| WHEN m.type = 'OTHER' AND m.account_from = a.id | ||
| THEN m.mount | ||
| ELSE 0 | ||
| END | ||
| ), 0) AS movement_total | ||
| FROM users AS u | ||
| INNER JOIN accounts AS a ON u.id = a.user_id | ||
| LEFT JOIN movements AS m ON a.id IN (m.account_from, m.account_to) | ||
| GROUP BY u.id, u.name, a.account_id, a.mount) | ||
| SELECT account_id, | ||
| (initial_mount + movement_total) AS updated_balance | ||
| FROM account_balances | ||
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| LOOP | ||
| UPDATE accounts | ||
| SET mount = account_balance.updated_balance | ||
| WHERE account_id = account_balance.account_id; | ||
| END LOOP; | ||
| END | ||
| $$; |
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I don't think this is the exercise it is mentioned
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I understand you point here, but to get the result was not needed to persist that information
README.md
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| SELECT u.name || ' ' || u.last_name AS full_name, a.mount | ||
| FROM users AS u | ||
| INNER JOIN accounts AS a ON u.id = a.user_id | ||
| ORDER BY a.mount DESC | ||
| LIMIT 3; |
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This is not the actual result consider that you need to include the after movements from the movements table.
This is not considering the movements done
README.md
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| ```sql | ||
| SELECT id, mount | ||
| FROM accounts | ||
| WHERE accounts.id = '3b79e403-c788-495a-a8ca-86ad7643afaf' OR accounts.id = 'fd244313-36e5-4a17-a27c-f8265bc46590'; |
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Suggestion: here you can directly use IN to get both ids filtered
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In other hand you need to get the result based on after all movements
README.md
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| 50.75) | ||
| RETURNING * INTO movement; | ||
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| IF (SELECT mount FROM accounts WHERE id = movement.account_from) < movement.mount THEN |
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Bear in mind that you need to take a look over after movements values
README.md
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| FOR updated_account_record IN | ||
| UPDATE accounts | ||
| SET mount = CASE | ||
| WHEN id = movement.account_from THEN mount - movement.mount | ||
| WHEN id = movement.account_to THEN mount + movement.mount | ||
| END | ||
| WHERE id = movement.account_from | ||
| OR id = movement.account_to | ||
| RETURNING * | ||
| LOOP | ||
| RAISE INFO 'Updated account %', updated_account_record.id; | ||
| END LOOP; | ||
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| RAISE INFO 'Transaction successful'; | ||
| COMMIT; | ||
| END |
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I understand your point in here but this will change how the process is managed and will ignore the limit under the after make movements
| UPDATE accounts | ||
| SET mount = mount - record.mount | ||
| WHERE id = record.account_from | ||
| RETURNING * INTO accounts_record; | ||
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