Course Content

Intermediate SQL

## Intermediate SQL

# Total Ride Time for Each Subway Line Challenge

The construction company has decided to **increase the number of stations on the Yellow metro line**.

Our next task is to find **the turnaround time for each line**. It's important for the company to **ensure that they can close the Yellow line** for maintenance and expansion by adding new metro stations, so it's crucial for them not to inconvenience passengers too much.

Therefore, we need to **find the total turnaround time** for the train by summing the time to each station (using the `SUM()`

function).

Note:

If we simply calculate the sum of the time to each station, it will be the

train's time from one end station to the other. However, it's also important for us to know thetotal turnaround timefor the train along the metro line. To achieve this, we need tomultiply the sum by 2.

To understand how to do this task, let's consider an **example** with an `employees`

table.

Suppose we need to find the **department with the highest average monthly salary**.

For this, we can use the following query:

`SELECT department, AVG(salary) / 12 AS average_monthly_salary FROM employees GROUP BY department ORDER BY average_monthly_salary DESC`

Thus, we **obtain the necessary data** as a result.

Let's return to the **task** because the workers **await our verdict** on the expansion of the metro station.

Here is the preview of a `metro_travel_time`

table we are working with:

Task

Calculate the **turnaround time** for each of the metro lines. To do this, use `SUM()`

, **group the data**, and order in ascending order. The **company already trusts you**, as you have helped them a lot before.

Note:

Name the new column

`turnaround_time`

so that your solution can be successfully tested. Also, don't forget tomultiplythe sum of timeby 2.

Task

Calculate the **turnaround time** for each of the metro lines. To do this, use `SUM()`

, **group the data**, and order in ascending order. The **company already trusts you**, as you have helped them a lot before.

Note:

Name the new column

`turnaround_time`

so that your solution can be successfully tested. Also, don't forget tomultiplythe sum of timeby 2.

Everything was clear?

# Total Ride Time for Each Subway Line Challenge

The construction company has decided to **increase the number of stations on the Yellow metro line**.

Our next task is to find **the turnaround time for each line**. It's important for the company to **ensure that they can close the Yellow line** for maintenance and expansion by adding new metro stations, so it's crucial for them not to inconvenience passengers too much.

Therefore, we need to **find the total turnaround time** for the train by summing the time to each station (using the `SUM()`

function).

Note:

If we simply calculate the sum of the time to each station, it will be the

train's time from one end station to the other. However, it's also important for us to know thetotal turnaround timefor the train along the metro line. To achieve this, we need tomultiply the sum by 2.

To understand how to do this task, let's consider an **example** with an `employees`

table.

Suppose we need to find the **department with the highest average monthly salary**.

For this, we can use the following query:

`SELECT department, AVG(salary) / 12 AS average_monthly_salary FROM employees GROUP BY department ORDER BY average_monthly_salary DESC`

Thus, we **obtain the necessary data** as a result.

Let's return to the **task** because the workers **await our verdict** on the expansion of the metro station.

Here is the preview of a `metro_travel_time`

table we are working with:

Task

Calculate the **turnaround time** for each of the metro lines. To do this, use `SUM()`

, **group the data**, and order in ascending order. The **company already trusts you**, as you have helped them a lot before.

Note:

Name the new column

`turnaround_time`

so that your solution can be successfully tested. Also, don't forget tomultiplythe sum of timeby 2.

Task

**turnaround time** for each of the metro lines. To do this, use `SUM()`

, **group the data**, and order in ascending order. The **company already trusts you**, as you have helped them a lot before.

Note:

`turnaround_time`

so that your solution can be successfully tested. Also, don't forget tomultiplythe sum of timeby 2.

Everything was clear?

# Total Ride Time for Each Subway Line Challenge

The construction company has decided to **increase the number of stations on the Yellow metro line**.

Our next task is to find **the turnaround time for each line**. It's important for the company to **ensure that they can close the Yellow line** for maintenance and expansion by adding new metro stations, so it's crucial for them not to inconvenience passengers too much.

Therefore, we need to **find the total turnaround time** for the train by summing the time to each station (using the `SUM()`

function).

Note:

If we simply calculate the sum of the time to each station, it will be the

train's time from one end station to the other. However, it's also important for us to know thetotal turnaround timefor the train along the metro line. To achieve this, we need tomultiply the sum by 2.

To understand how to do this task, let's consider an **example** with an `employees`

table.

Suppose we need to find the **department with the highest average monthly salary**.

For this, we can use the following query:

`SELECT department, AVG(salary) / 12 AS average_monthly_salary FROM employees GROUP BY department ORDER BY average_monthly_salary DESC`

Thus, we **obtain the necessary data** as a result.

Let's return to the **task** because the workers **await our verdict** on the expansion of the metro station.

Here is the preview of a `metro_travel_time`

table we are working with:

Task

**turnaround time** for each of the metro lines. To do this, use `SUM()`

, **group the data**, and order in ascending order. The **company already trusts you**, as you have helped them a lot before.

Note:

`turnaround_time`

so that your solution can be successfully tested. Also, don't forget tomultiplythe sum of timeby 2.

Task

**turnaround time** for each of the metro lines. To do this, use `SUM()`

, **group the data**, and order in ascending order. The **company already trusts you**, as you have helped them a lot before.

Note:

`turnaround_time`

so that your solution can be successfully tested. Also, don't forget tomultiplythe sum of timeby 2.

Everything was clear?

The construction company has decided to **increase the number of stations on the Yellow metro line**.

**the turnaround time for each line**. It's important for the company to **ensure that they can close the Yellow line** for maintenance and expansion by adding new metro stations, so it's crucial for them not to inconvenience passengers too much.

**find the total turnaround time** for the train by summing the time to each station (using the `SUM()`

function).

Note:

train's time from one end station to the other. However, it's also important for us to know thetotal turnaround timefor the train along the metro line. To achieve this, we need tomultiply the sum by 2.

To understand how to do this task, let's consider an **example** with an `employees`

table.

Suppose we need to find the **department with the highest average monthly salary**.

For this, we can use the following query:

Thus, we **obtain the necessary data** as a result.

**task** because the workers **await our verdict** on the expansion of the metro station.

Here is the preview of a `metro_travel_time`

table we are working with:

Task

**turnaround time** for each of the metro lines. To do this, use `SUM()`

, **group the data**, and order in ascending order. The **company already trusts you**, as you have helped them a lot before.

Note:

`turnaround_time`

so that your solution can be successfully tested. Also, don't forget tomultiplythe sum of timeby 2.