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Challenge 2 - Gabriel Echeverria #38

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Challenge 2 - Gabriel Echeverria #38

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ac9e770
feat: add new version for the challenge
ederivero Apr 7, 2023
7c9ca1c
chore: resolve comments
ederivero Apr 28, 2023
7fd8fa3
chore: resolve comments
ederivero Apr 28, 2023
45a9230
Finish challenge 2
Gecheverria Sep 9, 2024
5d5d9f5
Address challenge issues
Gecheverria Sep 10, 2024
be63df4
Address PR Comments
Gecheverria Sep 11, 2024
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284 changes: 234 additions & 50 deletions README.md
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
<p align="center" style="background-color:white">
<a href="https://www.ravn.co/" rel="noopener">
<img src="https://www.ravn.co/img/logo-ravn.png" alt="RAVN logo"></a>
<img src="src/ravn_logo.png" alt="RAVN logo" width="150px"></a>
</p>
<p align="center">
<a href="https://www.postgresql.org/" rel="noopener">
Expand Down Expand Up @@ -41,7 +41,7 @@ Open your terminal and run the follows commands:
1. This will create a container for postgresql:

```
docker run --name nerdery-container -e POSTGRES_PASSWORD=password123 -p 5432:5432 -d --rm postgres:13.0
docker run --name nerdery-container -e POSTGRES_PASSWORD=password123 -p 5432:5432 -d --rm postgres:15.2
```

2. Now, we access the container:
Expand All @@ -56,10 +56,15 @@ docker exec -it -u postgres nerdery-container psql
create database nerdery_challenge;
```

5. Close the database connection:
```
\q
```

4. Restore de postgres backup file

```
cat /.../src/dump.sql | docker exec -i nerdery-container psql -U postgres -d nerdery_challenge
cat /.../dump.sql | docker exec -i nerdery-container psql -U postgres -d nerdery_challenge
```

- Note: The `...` mean the location where the src folder is located on your computer
Expand All @@ -69,84 +74,263 @@ cat /.../src/dump.sql | docker exec -i nerdery-container psql -U postgres -d ner

## 📊 Excersises <a name = "excersises"></a>

Now it's your turn to write SQL querys to achieve the following results:
Now it's your turn to write SQL queries to achieve the following results (You need to write the query in the section `Your query here` on each question):

1. Count the total number of states in each country.
1. Total money of all the accounts group by types.

```
Your query here
SELECT type, SUM(mount)
FROM accounts
GROUP BY type
```

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

2. How many employees do not have supervisores.
2. How many users with at least 2 `CURRENT_ACCOUNT`.

```
Your query here
WITH AccountTotal AS (
SELECT a.user_id, COUNT(a.account_id)
FROM accounts AS a
WHERE a.type = 'CURRENT_ACCOUNT'
GROUP BY a.user_id
)
SELECT COUNT(user_id) AS total_accounts_multiple_current
FROM AccountTotal
WHERE COUNT > 1;
```

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

3. List the top five offices address with the most amount of employees, order the result by country and display a column with a counter.
3. List the top five accounts with more money.

```
Your query here
SELECT concat(u.name, ' ', u.last_name) AS user, a.account_id, a.mount
FROM accounts AS a
JOIN users AS u ON a.user_id = u.id
ORDER BY mount DESC
LIMIT 5
```

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

4. Three supervisors with the most amount of employees they are in charge.
4. Get the three users with the most money after making movements.

```
Your query here
SELECT u.name,
SUM(Case
WHEN m.type = 'IN' THEN m.mount
WHEN m.type = 'OUT' THEN -m.mount
WHEN m.type = 'OTHER' THEN -m.mount
else
COALESCE(CASE WHEN m.account_to = a.id THEN m.mount ELSE 0 END, 0) -
COALESCE(CASE WHEN m.account_from = a.id THEN m.mount ELSE 0 END, 0)
END
) AS total_balance
FROM users AS u
JOIN accounts AS a ON u.id = a.user_id
JOIN movements AS m ON a.id = m.account_from OR a.id = m.account_to
GROUP BY u.id
ORDER BY total_balance DESC
LIMIT 3
;
```

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

5. How many offices are in the state of Colorado (United States).
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

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):
```
Yes, because the amount exceeds the avialable funds the user has.
```

e. If the transaction fails, make the correction on step _c_ to avoid the failure:
```
DO $$
DECLARE
user_balance DOUBLE PRECISION;

BEGIN

SELECT mount
INTO user_balance
FROM accounts
WHERE id = '3b79e403-c788-495a-a8ca-86ad7643afaf';

IF user_balance > 731823.56 THEN
INSERT INTO movements (id, type, account_from, account_to, mount, created_at, updated_at)
VALUES (
uuid_generate_v4(),
'OUT',
'3b79e403-c788-495a-a8ca-86ad7643afaf',
NULL,
731823.56,
NOW(),
NOW()
);
ELSE
RAISE EXCEPTION 'Insufficient funds for user';
END IF;

COMMIT;

EXCEPTION
WHEN OTHERS THEN
ROLLBACK;
END $$;
```

f. Once the transaction is correct, make a commit
```
UPDATE accounts
SET mount = (
SELECT SUM(Case
WHEN m.type = 'IN' THEN m.mount
WHEN m.type = 'OUT' THEN -m.mount
WHEN m.type = 'OTHER' THEN -m.mount
else
COALESCE(CASE WHEN m.account_to = a.id THEN m.mount ELSE 0 END, 0) -
COALESCE(CASE WHEN m.account_from = a.id THEN m.mount ELSE 0 END, 0)
END
) AS balance
FROM accounts AS a
JOIN movements AS m ON a.id = m.account_from
WHERE a.id = '3b79e403-c788-495a-a8ca-86ad7643afaf'
)
WHERE id = '3b79e403-c788-495a-a8ca-86ad7643afaf';

UPDATE accounts
SET mount = (
SELECT SUM(Case
WHEN m.type = 'IN' THEN m.mount
WHEN m.type = 'OUT' THEN -m.mount
WHEN m.type = 'OTHER' THEN -m.mount
else
COALESCE(CASE WHEN m.account_to = a.id THEN m.mount ELSE 0 END, 0) -
COALESCE(CASE WHEN m.account_from = a.id THEN m.mount ELSE 0 END, 0)
END
) AS balance
FROM accounts AS a
JOIN movements AS m ON a.id = m.account_from
WHERE a.id = 'fd244313-36e5-4a17-a27c-f8265bc46590'
)
WHERE id = 'fd244313-36e5-4a17-a27c-f8265bc46590';

INSERT INTO movements (id, type, account_from, account_to, mount, created_at, updated_at)
VALUES (
gen_random_uuid(),
'TRANSFER',
'3b79e403-c788-495a-a8ca-86ad7643afaf',
'fd244313-36e5-4a17-a27c-f8265bc46590',
50.75,
NOW(),
NOW()
);

UPDATE accounts
SET mount = (
SELECT SUM(a.mount - 50.75) AS balance
FROM accounts AS a
JOIN movements AS m ON a.id = m.account_from
WHERE a.id = '3b79e403-c788-495a-a8ca-86ad7643afaf'
)
WHERE id = '3b79e403-c788-495a-a8ca-86ad7643afaf';

DO $$
DECLARE
user_balance DOUBLE PRECISION;

BEGIN

SELECT mount
INTO user_balance
FROM accounts
WHERE id = '3b79e403-c788-495a-a8ca-86ad7643afaf';

IF user_balance > 731823.56 THEN
INSERT INTO movements (id, type, account_from, account_to, mount, created_at, updated_at)
VALUES (
uuid_generate_v4(),
'OUT',
'3b79e403-c788-495a-a8ca-86ad7643afaf',
NULL,
731823.56,
NOW(),
NOW()
);
ELSE
RAISE EXCEPTION 'Insufficient funds for user';
END IF;

COMMIT;

EXCEPTION
WHEN OTHERS THEN
ROLLBACK;
END $$;
```

e. How much money the account `fd244313-36e5-4a17-a27c-f8265bc46590` have:
```
SELECT concat(u.name, ' ', u.last_name) AS user, SUM((CASE WHEN m.type = 'IN' THEN m.mount ELSE - m.mount END) + a.mount) AS net_amount
FROM users AS u
JOIN accounts AS a ON u.id = a.user_id
JOIN movements AS m ON m.account_from = a.id
WHERE a.id = 'fd244313-36e5-4a17-a27c-f8265bc46590'
GROUP BY u.name, u.last_name, u.email
ORDER BY net_amount DESC;
```


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

```
Your query here
SELECT concat(u.name, ' ', u.last_name) AS user, u.email, a.account_id, a.mount, m.account_to, m.account_from, m.mount, m.type
FROM users AS u
JOIN accounts AS a ON u.id = a.user_id
JOIN movements AS m ON a.id = m.account_to OR a.id = m.account_from
WHERE a.id = '3b79e403-c788-495a-a8ca-86ad7643afaf';
```

<p align="center">
<img src="src/results/result5.png" alt="result_5"/>
</p>

6. The name of the office with its number of employees ordered in a desc.
7. The name and email of the user with the highest money in all his/her accounts

```
Your query here
SELECT concat(u.name, ' ', u.last_name) AS user, u.email, SUM(Case
WHEN m.type = 'IN' THEN m.mount
WHEN m.type = 'OUT' THEN -m.mount
WHEN m.type = 'OTHER' THEN -m.mount
else
COALESCE(CASE WHEN m.account_to = a.id THEN m.mount ELSE 0 END, 0) -
COALESCE(CASE WHEN m.account_from = a.id THEN m.mount ELSE 0 END, 0)
END
) AS net_amount
FROM users AS u
JOIN accounts AS a ON u.id = a.user_id
JOIN movements AS m ON m.account_from = a.id
GROUP BY u.name, u.last_name, u.email
ORDER BY net_amount DESC
LIMIT 1;
```

<p align="center">
<img src="src/results/result6.png" alt="result_6"/>
</p>

7. The office with more and less employees.

```
Your query here
```

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

8. Show the uuid of the employee, first_name and lastname combined, email, job_title, the name of the office they belong to, the name of the country, the name of the state and the name of the boss (boss_name)
8. Show all the movements for the user `[email protected]` order by account type and created_at on the movements table

```
Your query here
SELECT u.email, m.type, a.account_id, m.account_from, m.account_to, m.created_at
FROM movements AS m
JOIN accounts AS a ON m.account_from = a.id OR m.account_to = a.id
JOIN users AS u ON a.user_id = u.id
WHERE u.email = '[email protected]'
ORDER BY a.type, m.created_at DESC;
```

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