SQL Select vs Multiple Tables

I just completed the Codeacademy SQL Fundamentals course: https://www.codecademy.com/paths/data-analyst/tracks/dsf-learn-sql/modules/dsf-review-sql/informationals/review-fundamentals-of-sql

I want to make sure I understand the difference between queries and manipulation:
When I use the SELECT command, I am only changing how the tables look temporarily, to run an analysis or get some kind of results. But, I’m not actually changing or manipulating the tables.

When I use the commands JOIN or UNION… those are also only temporary ways to view tables in a combined fashion, correct?

So: how do I convert these SELECT commands and update the tables I’m working on? If I understand correctly, this would be with the CREATE TABLE, INSERT, ALTER TABLE, DELETE and UPDATE commands. So: if I use these, than I’m manipulating and changing the actual tables. Is this correct?

Thank you for your support.


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You’re not changing the tables. You’re selecting rows of information from the tables based on whatever conditions you apply in your query.


Yep. You’re changing the existing structure of tables in a DB.

If they are available, I would suggest downloading the SQL Cheatsheets for reference.

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Thank you! Yes, I’ve got the cheatseets bookmarked. Just wanted to double check I was understanding the difference correctly.