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MIN/MAX vs ORDER BY and LIMIT
...oks like MIN() is able to simply pluck the smallest value from the index ('Select tables optimized away' and 'NULL' rows) whereas the SORT and LIMIT still needs needs to do an ordered traversal of the index (106,000 rows). The actual performance impact is probably negligible.
It looks like MIN() i...
Quicksort: Choosing the pivot
...states "Hoare suggested partitioning around the median of several randomly selected lines. Sedgewick [...] recommended choosing the median of the first [...] last [...] and middle". This indicates that both techniques for 'median-of-three' are known in the literature. (Update 2014-11-23: The articl...
Difference between ActionBarSherlock and ActionBar Compatibility
...ar (CAB) a menu that takes over the action bar, used for example for multi select (http://developer.android.com/design/patterns/new-4-0.html) This is a ICS feature (!) For this, an implementation of the ActionMode class (introduced in API level 11) had to be introduced into the ActionbarSherlock lib...
Why does installing Nokogiri on Mac OS fail with libiconv is missing?
...ed to install xCode command tools to allow you to install libiconv.
xcode-select --install
then install a newer version of libiconv
brew install libiconv
then install your gem
gem install nokogiri -- --with-iconv-dir=/usr/local/Cellar/libiconv/1.14
...
How can I convert a hex string to a byte array? [duplicate]
...gth)
.Where(x => x % 2 == 0)
.Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
.ToArray();
}
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Delete all the queues from RabbitMQ?
...oto Policies tab(on the right side)
Add Policy
Fill Fields
Virtual Host: Select
Name: Expire All Policies(Delete Later)
Pattern: .*
Apply to: Queues
Definition: expires with value 1 (change type from String to Number)
Save
Checkout Queues tab again
All Queues must be deleted
And don't forget remo...
The import android.support cannot be resolved
...Libraries tab. There click the Add External JARs Button on the Right pane.
Select the android-support-v4.jar file, usually the path for the Jar file is :
YOUR_DRIVE\android-sdks\extras\android\support\v4\android-support-v4.jar
After adding android-support-v4.jar Library, navigate to the Order and E...
sql ORDER BY multiple values in specific order?
...
You can order by a selected column or other expressions.
Here an example, how to order by the result of a case-statement:
SELECT col1
, col2
FROM tbl_Bill
WHERE col1 = 0
ORDER BY -- order by case-statement
CASE WHEN tbl_Bi...
Style disabled button with CSS
...ts.
For browsers/devices supporting CSS2 only, you can use the [disabled] selector.
As with the image, don't put an image in the button. Use CSS background-image with background-position and background-repeat. That way, the image dragging will not occur.
Selection problem: here is a link to the s...
“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
...int, unique key (u));
mysql> insert into foo (u) values (10);
mysql> select * from foo;
+----+------+
| id | u |
+----+------+
| 1 | 10 |
+----+------+
mysql> show create table foo\G
CREATE TABLE `foo` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`u` int(11) DEFAULT NULL,
...