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Tactics for using PHP in a high-load site
...l you measure and compare your changes.
For example, for many years, the MySQL query cache was the solution to all of our performance problems. If your site was slow, MySQL experts suggested turning the query cache on. It turns out that if you have a high write load, the cache is actually cripplin...
Set NOW() as Default Value for datetime datatype?
...
As of MySQL 5.6.5, you can use the DATETIME type with a dynamic default value:
CREATE TABLE foo (
creation_time DATETIME DEFAULT CURRENT_TIMESTAMP,
modification_time DATETIME ON UPDATE CURRENT_TIMESTAMP
)
Or even...
How to update column with null value
I am using mysql and need to update a column with a null value. I have tried this many different ways and the best I have gotten is an empty string.
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MySQL: Quick breakdown of the types of joins [duplicate]
I would like a quick breakdown of the types of MySQL joins. I know of these, the rest I am not sure what they mean.
3 Answe...
How can I make SQL case sensitive string comparison on MySQL?
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http://dev.mysql.com/doc/refman/5.0/en/case-sensitivity.html
The default character set and collation are latin1 and latin1_swedish_ci, so nonbinary string comparisons are case insensitive by default. This means that if you search wi...
Variable declaration placement in C
...ly if the curlies are part of a block (not if they are part of a struct or union declaration or a braced initializer.)
– Jens
Jun 18 '13 at 19:39
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Simple way to calculate median with MySQL
...the simplest (and hopefully not too slow) way to calculate the median with MySQL? I've used AVG(x) for finding the mean, but I'm having a hard time finding a simple way of calculating the median. For now, I'm returning all the rows to PHP, doing a sort, and then picking the middle row, but surely ...
How to avoid mysql 'Deadlock found when trying to get lock; try restarting transaction'
...AL 900 SECOND
ORDER BY id
) u;
Another thing to keep in mind is that mysql documentation suggest that in case of a deadlock the client should retry automatically. you can add this logic to your client code. (Say, 3 retries on this particular error before giving up).
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Retrieving the last record in each group - MySQL
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MySQL 8.0 now supports windowing functions, like almost all popular SQL implementations. With this standard syntax, we can write greatest-n-per-group queries:
WITH ranked_messages AS (
SELECT m.*, ROW_NUMBER() OVER (PARTIT...
Show MySQL host via SQL Command
...last comment,
I don't think you can resolve IP for the hostname using pure mysql function,
as it require a network lookup, which could be taking long time.
However, mysql document mention this :-
resolveip google.com.sg
docs :- http://dev.mysql.com/doc/refman/5.0/en/resolveip.html
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