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By: Apachez
Is this a MySQL Optimizer bug (which we could expect to be fixed in near future) or is this “by design” for the next couple of years ?I mean the UNION is a nice workaround but needs more code and logic...
View ArticleBy: MySQL Performance Blog » MySQL: Followup on UNION for query optimization,...
[…] Few days ago I wrote an article about using UNION to implement loose index scan. […]
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By: James Day
Apachez, one of many areas where it’s known that the optimizer can be improved. They are gradually being done, no particular schedule for when each one is done. Other than more slowly than we’d all...
View ArticleBy: How adding another table to JOIN can improve performance ? | MySQL...
[…] have described couple of solutions to this problem – using IN list instead of range or UNION which however require […]
View ArticleBy: How to select the first/least/max row per group in SQL at Xaprb
[…] Peter Zaitsev has written in detail about this technique, so I won’t go into it too much more here. If it suits your purposes, it can be a very good solution. […]
View ArticleBy: Mark
Its 3 years later, has this been fixed? If so, in what version of MySQL?Thanks!
View ArticleBy: How to select the first/least/max row per group in SQL | Wilson80s
[…] Peter Zaitsev has written in detail about this technique, so I won’t go into it too much more here. If it suits your purposes, it can be a very good solution. […]
View ArticleBy: Jindra
Thanks, helped me to optimize query with agregate function on table with multiple key:table: Create table tabData ( channel_id Int NOT NULL, date_time Datetime NOT NULL, value Double NOT NULL, Primary...
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By: Spyd
Hey, i found this page while googling for more information after i implemented something exactly like this! I thought i had done something “dirty” but now i’m happy that this “tricky” method is...
View ArticleBy: You know, for kids!
In mysql> SELECT name FROM people WHERE age=18 AND zip IN (12345,12346, 12347) -> UNION ALL -> SELECT name FROM people WHERE age=19 AND zip IN (12345,12346, 12347) -> UNION ALL -> SELECT...
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