# FAQ: Calculating Churn - Multiple Month: Create Months Temporary Table

This community-built FAQ covers the “Multiple Month: Create Months Temporary Table” exercise from the lesson “Calculating Churn”.

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## FAQs on the exercise Multiple Month: Create Months Temporary Table

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FYI I had trouble with getting the answer to the first question:

"1.

We will be using the months as a temporary table (using `WITH` ) in the churn calculation.

Create the `months` temporary table using `WITH` and `SELECT` everything from it so that you can see the structure.

We need a table for January, February, and March of 2017."

I found the concept to be pretty simply, but was stumped for awhile. Turns out it was adding a few commas that I didn’t need. I thought I would convey that here:

WITH months AS (
SELECT STATEMENT (no comma at the end)
UNION
SELECT STATEMENT (no comma at the end)
UNION
SELECT STATEMENT (no comma at the end)
)
SELECT *
FROM months;

4 Likes

Hi, In slide 4 I was getting an error message reading something like “be sure your table has 3 months in it” when I displayed my code. Once I decided to let Codecademy give me their answer, I realized the only difference was that my February row’s “last_day” was 31 while the answer’s was 28.

Suggesting that a reminder about the number of days in Feb may be a better hint for that issue. Thanks for the new path!

11 Likes

Dude thank you lol I was struggling all over forgetting the length of the month of February. I think the most valuable lesson here for a new programmer is that paying attention to detail needs to be brought to a WHOLE other level. Thanks for the tip mckinley

4 Likes

hi, why we not use CREATE TABLE and INSERT INTO? for new table?

with months as
(
SELECT
‘2017-01-01’ AS first_day,
‘2017-01-31’ AS last_day
union
SELECT
‘2017-02-01’ AS first_day,
‘2017-02-28’ AS last_day
union
SELECT
‘2017-03-01’ AS first_day,
‘2017-03-31’ AS last_day)
SELECT *
FROM months;

hi, why we not use CREATE TABLE and INSERT INTO? for new table?

with months as
(
SELECT
‘2017-01-01’ AS first_day,
‘2017-01-31’ AS last_day
union
SELECT
‘2017-02-01’ AS first_day,
‘2017-02-28’ AS last_day
union
SELECT
‘2017-03-01’ AS first_day,
‘2017-03-31’ AS last_day)
SELECT *
FROM months;

1 Like

I was thinking to split rows into months columns with something like:

``````select *
from subscriptions
group by strftime('%Y %m', subscription_start);
``````

can you tell me why it does not work as expected ?

What am I doing wrong with my code here?

with months as
(
SELECT
‘2017-01-01’ AS first_day,
‘2017-01-31’ AS last_day
union
SELECT
‘2017-02-01’ AS first_day,
‘2017-02-28’ AS last_day
union
SELECT
‘2017-03-01’ AS first_day,
‘2017-03-31’ AS last_day
)
SELECT *
FROM months;

your quotation marks

awesome thanks for the feedback

Wow thank you! I totally didn’t realise this for a long time.

Hi there, I think that’s because we need temporary table and ‘WITH’ is the way.

Is there another way to create a temporary table from scratch? To me the UNION statement does not seem that convenient.

Is there a possibility to include the INSERT INTO Statement into a temporary table created by the WITH statement? I`ve tried to…emphasis on tried what am I doing wrong?

WITH months AS(
SELECT ‘2017-01-01’ AS first_day, ‘2017-01-31’ AS last_day
INSERT INTO months (first_day, last_day)
VALUES
(‘2017-02-01’,‘2017-02-28’),
(‘2017-03-01’,‘2017-03-31’)
)
SELECT * FROM months;

What about February 29?

Agree this is probably the most important lesson to be learned. All the times I got stuck it turned out to be because of some tiny error, like a . instead of _ or an upper case instead of lower case letter. In the last exercise with the glasses I got stuck with writing if number_of_pairs = “3” and couldn’t make the code work for an eternity, until I realised in the table it said “3 pairs”. Sigh!

A bit confused about about the aliasing in this exercise, why do we write ( SELECT “2017-02-01” AS first_day ) here, but (SELECT COUNT(*) AS “First step”), in other SELECT queries? To be clearer, why do we need the quotation marks sometimes when aliasing and sometimes not?

2 Likes

I think i got the bit to setup the dates, ok but incase i leap year i had 29 days in february not too worry, this is the solution you need months at the top with months as and then
SELECT * select all table columns with the star

FROM months; from months using the semi colon to end statement…

Thanks

Ian

WITH months as

(SELECT

‘2017-01-01’ as first_day,

‘2017-01-31’ as last_day

UNION

SELECT

‘2017-02-01’ as first_day,

‘2017-02-28’ as last_day

UNION

SELECT

‘2017-03-01’ as first_day,

‘2017-03-31’ as last_day

)

SELECT *

FROM months; semi colon

I was wondering this too but it is only in a leap year , so my guess is too make it simpler it is 28 days thanks
Ian

my guess is this is not a temporary table that you are making , you are trying to select year and month from all columns from the subscriptions table imho

thanks

Ian

I think this is what you mean

CORRECT SOLUTION:

WITH months as(
SELECT
‘2017-01-01’ AS first_day,
‘2017-01-31’ AS last_day
UNION
SELECT
‘2017-02-01’ AS first_day,
‘2017-02-28’ AS last_day
UNION
SELECT
‘2017-03-01’ AS first_day,
‘2017-03-31’ AS last_day
)

SELECT * FROM months;