大约有 40,000 项符合查询结果（耗时：0.0823秒） [XML]
COUNT DISTINCT with CONDITIONS
...count(distinct tag) as tag_count,
count(distinct (case when entryId > 0 then tag end)) as positive_tag_count
from
your_table_name;
The first count(distinct...) is easy.
The second one, looks somewhat complex, is actually the same as the first one, except that you use case...when clause. In ...
How do I parse JSON with Objective-C?
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With the perspective of the OS X v10.7 and iOS 5 launches, probably the first thing to recommend now is NSJSONSerialization, Apple's supplied JSON parser. Use third-party options only as a fallback if you find that class unavailable at runtime.
So, for exampl...
How do I draw a grid onto a plot in Python?
...lot using pylab in Python and now I would like to superimpose a grid of 10x10 onto the scatter plot. How do I do that?
5 ...
Maven project version inheritance - do I have to specify the parent version?
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EDIT: Since Maven 3.5.0 there is a nice solution for this using ${revision} placeholder. See FrVaBe's answer for details. For previous Maven versions see my original answer below.
No, there isn't. You always have to specify parent's version. Fo...
C# short/long/int literal format?
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var d = 1.0d; // double
var d0 = 1.0; // double
var d1 = 1e+3; // double
var d2 = 1e-3; // double
var f = 1.0f; // float
var m = 1.0m; // decimal
var i = 1; // int
var ui = 1U; // uint
var ul = 1UL; // ulong
var l =...
Is SQL or even TSQL Turing Complete?
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Qantas 94 Heavy
14.4k1616 gold badges6060 silver badges7777 bronze badges
answered Sep 28 '11 at 7:59
Jan de VosJan de Vos
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An “and” operator for an “if” statement in Bash
...US} is empty. It would probably be better to do:
if ! [ "${STATUS}" -eq 200 ] 2> /dev/null && [ "${STRING}" != "${VALUE}" ]; then
or
if [ "${STATUS}" != 200 ] && [ "${STRING}" != "${VALUE}" ]; then
It's hard to say, since you haven't shown us exactly what is going wrong wit...
How to loop through all but the last item of a list?
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answered May 27 '09 at 9:04
freespacefreespace
15.1k33 gold badges3434 silver badges5555 bronze badges
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Transitions on the CSS display property
...rder: 1px solid #eee;
}
div > ul {
visibility: hidden;
opacity: 0;
transition: visibility 0s, opacity 0.5s linear;
}
div:hover > ul {
visibility: visible;
opacity: 1;
}
<div>
<ul>
<li>Item 1</li>
<li>Item 2</li>
<li&...
Capture key press (or keydown) event on DIV element
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302
(1) Set the tabindex attribute:
<div id="mydiv" tabindex="0" />
(2) Bind to keydown:
...