大约有 47,000 项符合查询结果（耗时：0.0411秒） [XML]
How do I get SUM function in MySQL to return '0' if no values are found?
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307
Use COALESCE to avoid that outcome.
SELECT COALESCE(SUM(column),0)
FROM table
WHERE ...
T...
What is the “-->” operator in C++?
...ised that the following snippet compiled and worked in both Visual Studio 2008 and G++ 4.4.
25 Answers
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How to get all possible combinations of a list’s elements?
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edited Jan 21 '09 at 12:52
answered Jan 21 '09 at 11:20
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CSS I want a div to be on top of everything
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dev.bv
93099 silver badges1616 bronze badges
answered Sep 14 '11 at 19:22
Skylar AndersonSkylar Anderson
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Node.js + Nginx - What now?
...ng like:
# the IP(s) on which your node server is running. I chose port 3000.
upstream app_yourdomain {
server 127.0.0.1:3000;
keepalive 8;
}
# the nginx server instance
server {
listen 80;
listen [::]:80;
server_name yourdomain.com www.yourdomain.com;
access_log /var/log/...
Why does ~True result in -2?
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240
int(True) is 1.
1 is:
00000001
and ~1 is:
11111110
Which is -2 in Two's complement1
1 Fl...
How to linebreak an svg text within javascript?
... occur, you can break your text into multiple <tspan>s, each with x="0" and dy="1.4em" to simulate actual lines of text. For example:
<g transform="translate(123 456)"><!-- replace with your target upper left corner coordinates -->
<text x="0" y="0">
<tspan x="0" dy...
Maven check for updated dependencies in repository
...lable:
[INFO] org.apache.maven:maven-artifact ........................ 2.0 -> 2.0.9
[INFO] org.apache.maven:maven-plugin-api ...................... 2.0 -> 2.0.9
[INFO] org.apache.maven:maven-project ....................... 2.0.2 -> 2.0.9
[INFO] org.codehaus.plexus:plexus-utils ........
Maven dependency for Servlet 3.0 API?
How can I tell Maven 2 to load the Servlet 3.0 API?
10 Answers
10
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Matplotlib: “Unknown projection '3d'” error
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First off, I think mplot3D worked a bit differently in matplotlib version 0.99 than it does in the current version of matplotlib.
Which version are you using? (Try running: python -c 'import matplotlib; print matplotlib."__version__")
I'm guessing you're running version 0.99, in which case you'll...