Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

✨ DB Nerdery Challenges Solutions II #53

Open
wants to merge 10 commits into
base: challenge-2
Choose a base branch
from
+508 −39
Open

✨ DB Nerdery Challenges Solutions II #53

Show file tree
Hide file tree
Changes from 9 commits
Commits
Show all changes
10 commits
Select commit Hold shift + click to select a range
a5c18e7
feat: add query solutions
marvnramos Nov 28, 2024
c39ec06
feat: add query solutions
marvnramos Nov 28, 2024
0df3795
add result images
marvnramos Nov 28, 2024
16625ac
feat: add new responses
Nov 29, 2024
8a18eaf
feat: add imges result
Nov 29, 2024
952432f
Add solutions into answer.sql
Nov 29, 2024
f9cb556
feat: fix exercise 4 result
Nov 29, 2024
91afe92
feat: fix solution
Nov 29, 2024
b69f77d
feat: updating fourth exercise solution
Nov 29, 2024
e33d47c
feat: solving pr suggestions
Dec 5, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
272 changes: 238 additions & 34 deletions README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@ docker run --name nerdery-container -e POSTGRES_PASSWORD=password123 -p 5432:543
```
docker exec -it -u postgres nerdery-container psql
```

C:\Users\arago\OneDrive\Escritorio\nerdery-repos\DB-Nerdery-Challenges\src\dump.sql
3. Create the database:

```
Expand All @@ -60,7 +60,7 @@ create database nerdery_challenge;
```
\q
```

C:\Users\arago\OneDrive\Escritorio\nerdery-repos\DB-Nerdery-Challenges\src\dump.sql
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

What does this mean?

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I was copying the dump.sql path and forgot to delete from readme file

4. Restore de postgres backup file

```
Expand All @@ -78,84 +78,288 @@ Now it's your turn to write SQL queries to achieve the following results (You ne

1. Total money of all the accounts group by types.

```sql
SELECT type, SUM(mount) AS total
FROM accounts
group by type
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nit: use uppercase for keywords

```
Your query here
```

<p align="center">
<img src="src/my-results/result1.png" alt="result_1"/>
</p>

2. How many users with at least 2 `CURRENT_ACCOUNT`.

```sql
SELECT count(u.name) as user_w_least_two_accounts
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nit: use uppercase with keywords

Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

What it is going to happen if for any reason do you have a null value in u.name?

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This will only count u.name fields with values and ignore null fields

FROM users AS u
INNER JOIN accounts AS a ON u.id = a.user_id
WHERE a.type = 'CURRENT_ACCOUNT'
HAVING count(a.id) >= 2;
```
Your query here
```

<p align="center">
<img src="src/my-results/result2.png" alt="result_2"/>
</p>

3. List the top five accounts with more money.

```sql
SELECT id, mount
FROM accounts
ORDER BY mount DESC
LIMIT 5;
```
Your query here
```

<p align="center">
<img src="src/my-results/result3.png" alt="result_3"/>
</p>

4. Get the three users with the most money after making movements.

```
Your query here
```sql
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

LOOP
UPDATE accounts
SET mount = account_balance.updated_balance
WHERE account_id = account_balance.account_id;
END LOOP;
END
$$;
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I don't think this is the exercise it is mentioned

Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I understand you point here, but to get the result was not needed to persist that information


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;
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

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

```

<p align="center">
<img src="src/my-results/result4.png" alt="result_4"/>
</p>

5. In this part you need to create a transaction with the following steps:

a. First, get the ammount for the account `3b79e403-c788-495a-a8ca-86ad7643afaf` and `fd244313-36e5-4a17-a27c-f8265bc46590` after all their movements.
b. Add a new movement with the information:
from: `3b79e403-c788-495a-a8ca-86ad7643afaf` make a transfer to `fd244313-36e5-4a17-a27c-f8265bc46590`
mount: 50.75
```sql
SELECT id, mount
FROM accounts
WHERE accounts.id = '3b79e403-c788-495a-a8ca-86ad7643afaf' OR accounts.id = 'fd244313-36e5-4a17-a27c-f8265bc46590';
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggestion: here you can directly use IN to get both ids filtered

Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

In other hand you need to get the result based on after all movements

```

<p align="center">
<img src="src/my-results/result5A.png" alt="result_5"/>
</p>

b. Add a new movement with the information:from: `3b79e403-c788-495a-a8ca-86ad7643afaf` make a transfer to `fd244313-36e5-4a17-a27c-f8265bc46590` mount: 50.75

```sql
DO
$$
DECLARE
movement RECORD;
updated_account_record RECORD;
BEGIN
INSERT INTO movements(id, type, account_from, account_to, mount)
VALUES (gen_random_uuid(),
'TRANSFER',
'3b79e403-c788-495a-a8ca-86ad7643afaf',
'fd244313-36e5-4a17-a27c-f8265bc46590',
50.75)
RETURNING * INTO movement;

IF (SELECT mount FROM accounts WHERE id = movement.account_from) < movement.mount THEN
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Bear in mind that you need to take a look over after movements values

RAISE INFO 'Invalid movement: Insufficient balance in account %. Rolling back.', movement.account_from;
ROLLBACK;
RETURN;
END IF;

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;

RAISE INFO 'Transaction successful';
COMMIT;
END
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

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

$$;
```
<p align="center">
<img src="src/my-results/result5B.png" alt="result_5"/>
</p>
c. Add a new movement with the information:
from: `3b79e403-c788-495a-a8ca-86ad7643afaf`
type: OUT
mount: 731823.56

* Note: if the account does not have enough money you need to reject this insert and make a rollback for the entire transaction

d. Put your answer here if the transaction fails(YES/NO):
```
Your answer
* Note: if the account does not have enough money you need to reject this insert and make a rollback for the entire transaction
```sql
DO
$$
DECLARE
record RECORD;
accounts_record RECORD;
BEGIN
INSERT INTO movements(id, type, account_from, account_to, mount)
VALUES (gen_random_uuid(), 'OUT', '3b79e403-c788-495a-a8ca-86ad7643afaf', NULL, 731823.56)
RETURNING * INTO record;

UPDATE accounts
SET mount = mount - record.mount
WHERE id = record.account_from
RETURNING * INTO accounts_record;

Comment on lines +300 to +304
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Same as above

IF accounts_record.mount < 0 THEN
RAISE NOTICE 'Invalid movement: Insufficient balance in account %. Rolling back.', record.account_from;
ROLLBACK;
RETURN;
END IF;

RAISE NOTICE 'Transaction successful: Movement ID %, Account ID %, New Balance %.',
record.id, accounts_record.id, accounts_record.mount;

COMMIT;
END
$$;
```

d. Put your answer here if the transaction fails(YES/NO):
failure:
<p align="center">
<img src="src/my-results/result5C.png" alt="result_5"/>
</p>
success:
<p align="center">
<img src="src/my-results/result5C2.png" alt="result_5"/>
</p>
e. If the transaction fails, make the correction on step _c_ to avoid the failure:
```
Your query

```sql
INSERT INTO movements(id, type, account_from, account_to, mount)
VALUES (gen_random_uuid(), 'OUT', '3b79e403-c788-495a-a8ca-86ad7643afaf', NULL, 1000.05)
RETURNING * INTO record;
```

f. Once the transaction is correct, make a commit
```
Your query
```sql
RAISE NOTICE 'Transaction successful: Movement ID %, Account ID %, New Balance %.',
record.id, accounts_record.id, accounts_record.mount;

COMMIT;
```

e. How much money the account `fd244313-36e5-4a17-a27c-f8265bc46590` have:
```sql
SELECT id, mount
FROM accounts
WHERE id = 'fd244313-36e5-4a17-a27c-f8265bc46590';
```
Your query
```

<p align="center">
<img src="src/my-results/result5E.png" alt="result_5"/>
</p>

6. All the movements and the user information with the account `3b79e403-c788-495a-a8ca-86ad7643afaf`

```SQL
WITH user_info AS (SELECT u.id AS user_id,
u.name || ' ' || u.last_name AS fullname,
u.email,
u.date_joined,
a.id AS account_id
FROM users u
INNER JOIN accounts a ON u.id = a.user_id
WHERE a.id = '3b79e403-c788-495a-a8ca-86ad7643afaf')
SELECT ui.fullname,
ui.email,
ui.date_joined,
m.type,
m.account_from,
m.account_to,
m.mount
FROM user_info ui
LEFT JOIN movements m
ON m.account_from = ui.account_id OR m.account_to = ui.account_id;
```
Your query here
```
<p align="center">
<img src="src/my-results/result6.png" alt="result_6"/>
</p>


7. The name and email of the user with the highest money in all his/her accounts

```
Your query here
```sql
WITH highest_account_mount AS (SELECT user_id, MAX(mount) AS max_mount
FROM accounts
GROUP BY user_id
ORDER BY max_mount DESC
LIMIT 1)

SELECT u.name || ' ' || u.last_name AS full_name,
u.email,
ham.max_mount AS total_money
FROM users AS u
INNER JOIN highest_account_mount AS ham ON u.id = ham.user_id;
```

<p align="center">
<img src="src/my-results/result7.png" alt="result_7"/>
</p>

8. Show all the movements for the user `Kaden.Gusikowski@gmail.com` order by account type and created_at on the movements table

```
Your query here
```sql
WITH user_info AS (SELECT u.id, u.email, a.id AS account_id
FROM users AS u
INNER JOIN accounts AS a ON u.id = a.user_id
WHERE u.email = 'Kaden.Gusikowski@gmail.com')
SELECT DISTINCT ui.email,
m.id AS id_movement,
m.type,
m.account_from,
m.account_to,
m.mount,
m.created_at
FROM movements m
INNER JOIN user_info ui ON m.account_from = ui.account_id OR m.account_to = ui.account_id
ORDER BY m.type, m.created_at;
```

<p align="center">
<img src="src/my-results/result8.png" alt="result_8"/>
</p>
Loading