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Re: Using Joins/Unions




On Tue, August 4, 2015 11:19, Ryan Coleman wrote:
> I have been a MySQL user and supporter for over a decade (since 2001) and
> I am almost ashamed to admit that I haven’t the faintest idea on how to do
> joins and unions.
>
> I have a specific query I would love to run…
>
> I have two tables, one with Unique data (“images”) and one with
> corresponding paths but many replicated records (“files”).
>
> I want to run a query that takes the results from /images/ and also
> searches /images.file/ as a LIKE statement from /files.path/, sort by
> /files.filesize/ in descending order returning just the first record
> (largest file size).  There may be up to 750 records from /images/ and
> thusly could be 3000+ from /files/.
>
> How on earth do I do this?
>
> —
> Ryan
First question, will there always be at least one record in the files
table for every record in the images table?  That controls the kind of
join you will use.  I don't think that a union is a player. Also, is there
a unique record ID in each of the table?
------
William R. Mussatto
Systems Engineer
http://www.csz.com
909-920-9154


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