大约有 42,000 项符合查询结果（耗时：0.0715秒） [XML]
SQL “select where not in subquery” returns no results
...emantically the same.
When it is nullable, NOT IN is different, since IN (and, therefore, NOT IN) return NULL when a value does not match anything in a list containing a NULL.
This may be confusing but may become more obvious if we recall the alternate syntax for this:
common_id = ANY
(
SELECT c...
What are some common uses for Python decorators? [closed]
...ple! No idea what it does though. An explanation what you are doing there, and how the decorator solves the problem would be very nice.
– MeLight
Jun 15 '14 at 16:00
8
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How to prevent favicon.ico requests?
...in a Web page is a good thing (normally).
However it is not always desired and sometime developers need a way to avoid the extra payload. For example an IFRAME would request a favicon without showing it.
Worst yet, in Chrome and Android an IFRAME will generate 3 requests for favicons:
"GET /favicon....
clang: how to list supported target architectures?
Currently I am interested in ARM in general and specifically iphone/android targets. But I just want to know more about clang, since it feels to play important role in the years to come.
...
What's the difference between require and require-dev? [duplicate]
I'm new to the composer and I would like to know the difference between require and require-dev .
The composer website doesn't offer a good explanation the difference between these two.
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jQuery ajax error function
...
The required parameters in an Ajax error function are jqXHR, exception and you can use it like below:
$.ajax({
url: 'some_unknown_page.html',
success: function (response) {
$('#post').html(response.responseText);
},
error: function (jqXHR, exception) {
var msg = ...
Calculate last day of month in JavaScript
...efox 2.0.0.17: Thu Jan 31 2008 00:00:00 GMT-0600 (Canada Central Standard Time)
Firefox 3.0.3: Thu Jan 31 2008 00:00:00 GMT-0600 (Canada Central Standard Time)
Google Chrome 0.2.149.30: Thu Jan 31 2008 00:00:00 GMT-0600 (Canada Central Standard Time)
Safari for Windows 3.1.2: Thu ...
Catching error codes in a shell pipe
...
If you really don't want the second command to proceed until the first is known to be successful, then you probably need to use temporary files. The simple version of that is:
tmp=${TMPDIR:-/tmp}/mine.$$
if ./a > $tmp.1
then
if ./b <$tmp.1 >$tmp.2
...
Looping through a hash, or using an array in PowerShell
...
Christian's answer works well and shows how you can loop through each hash table item using the GetEnumerator method. You can also loop through using the keys property. Here is an example how:
$hash = @{
a = 1
b = 2
c = 3
}
$hash.Keys | % { "...
What's the best way to set a single pixel in an HTML5 canvas?
...
There are two best contenders:
Create a 1×1 image data, set the color, and putImageData at the location:
var id = myContext.createImageData(1,1); // only do this once per page
var d = id.data; // only do this once per page
d[0] = r;
d[1] = g;
d[2] = b;
d[3] = a;
...