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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: alt.folklore.computers,comp.os.linux.misc
Subject: Re: The joy of FORTRAN
Date: Thu, 27 Feb 2025 21:39:25 -0000 (UTC)
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On Thu, 27 Feb 2025 12:04:15 +0000, The Natural Philosopher wrote:

>> Ummmmmm ... SQL from *anything* isn't especially "pleasant'  🙂
> 
> It is if you restrict yourself to just a few library bits that work
> [well]

I think the most complex query I’ve done is a 7-way table join.

> I found out early that MySQL was really really good at very simple
> queries but was abominably slow at processing complex ones and it was
> better to not try and write the One True SQL statement, but several
> simple ones and  to manipulate the data in C afterwards.

Quite the opposite. One of my jobs is to maintain and continue development 
of a system written in PHP for a client by some previous developer who 
only knew ... PHP. One of the reports it generates is a list of hours 
worked over a range of dates. The original code did a separate query for 
each date in the range. So the longer the interval, the slower it went. 
(E.g. a query covering 6 months could get pretty painful.) I replaced that 
code with a single query over the entire date range, where my code looped 
over the result records and grouped them accordingly for output.

Result: much faster results -- even a query covering 6 months would appear 
in just a few seconds.

Moral: the more information you give the query optimizer, the more 
efficiently you will get results.