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Do I need a Subquery?

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I think I need a Subquery to solve my latest issue, but am unsure.  (Boy am i rusty on SQL!!)

Simplified example...

Let's say that I have query #1 that joins a bunch of tables (too complicated to post here for now) and it's end result is the following...


| Plan   | Ver | Category |
| Basic | v2   | News       |
| Basic | v2   | Articles   |
| Basic | v2   | Op-Ed      |


Now for query #2 - the one I need help with - I am trying to do something like this...


FROM article AS a

WHERE (a.slug = $urlSlug) AND {a.category_id is equal to one of the Category values returned in Query #1



Edited by SaranacLake
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1 minute ago, requinix said:

You might not need a subquery. Depends what that "too complicated" query was. So just let us see it.

It involves joining 3-4 tables - some with composites keys.  I haven't written it yet.

Either way, query #1 will return a result set that might be anywhere from 1 to 15 "Category" values.  (Since the results will vary, that I why I was thinking query #1 would be in the WHERE part of query #2.


	WHERE a.category_id IN (query #1 results)



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19 hours ago, requinix said:

Okay. How about you write it, then come back and say what it is? Because like I said, depending on what it is, you may not need the subquery.

While I am doing that, care to give me a hint what the alternative might be?  🙂


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3 minutes ago, kicken said:

Maybe just adding another join to your "complicated" query that connects the articles table.

A-ha.  Yeah, I was thinking that is what you'd say.

No, I considered that, but in my ERD that wouldn't work because I have a fork like this...

	>|-------||-  MY_TABLE  -||-------<


(I am brushing up on MySQL so I can create a "test" database and try out my hypotheses!)


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