FAQ: Code Challenge: Queries - Code Challenge 3

This community-built FAQ covers the “Code Challenge 3” exercise from the lesson “Code Challenge: Queries”.

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This exercise can be found in the following Codecademy content:

Web Development
Data Science

FAQs on the exercise Code Challenge 3

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I am still confused with how the AND statement works. I tried the following code, it didn’t work-

SELECT name, gender, number
FROM babies
WHERE year = 1880

What am I getting wrong? Is AND only to be used when you’re doing operations on two different columns ?

you don’t need to use AND in this case. AND is used when you’re joining multiple conditions, like: where… and… and…

I’m not fully understanding what GROUP BY does.

In the first query I leave out ‘GROUP BY name’ and the second one I include it. I’m not sure why there is a difference in query results. For instance, why is ‘John’ and ‘William’ not included in the second query results?

that´s an interesting question. i would have also expected the same result.
nevertheless name is the primary key, and grouping by a primary key does not really make sense, innit?