大约有 46,000 项符合查询结果（耗时：0.0492秒） [XML]
How to force LINQ Sum() to return 0 while source collection is empty
...word
&& l.Property.PropertyId == PropertyId)
.Select(l => l.Amount)
.DefaultIfEmpty(0)
.Sum();
This way, your query will only select the Amount field. If the collection is empty, it will return one element with the value of 0 and then the sum will ...
Postgres could not connect to server
...
Had a similar problem; a pid file was blocking postgres from starting up. To fix it:
$ rm /usr/local/var/postgres/postmaster.pid
$ brew services restart postgresql
and then all is well.
share
|
...
MAMP Pro 3.05 on Mavericks updated to Yosemite - Apache does not start
...
Just found workaround from MAMP on Twitter
Workaround for the 10.10 Preview 5 bug:
Rename the file “envvars” located in into “_envvars”
share
|
...
Why is WinRT unmanaged? [closed]
...e runtime implementation detail. The collector for .NET is very different from the collector for Javascript for example. The native objects created in either must observe the very strict rules of the collector. Which in turn means that they would have had to create WinRT versions that are specifi...
XPath: How to select elements based on their value?
...st thing is when using [], there are only two types of data:
[number] to select a node from node-set
[bool] to filter a node-set from node-set
In this case, the value is evaluated to boolean by function boolean(), and there is a rule:
Filters are always evaluated with respect to a context.
...
CSS3 selector :first-of-type with class name?
Is it possible to use the CSS3 selector :first-of-type to select the first element with a given class name? I haven't been successful with my test so I'm thinking it's not?
...
Syntax for a single-line Bash infinite while loop
...ation of semicolons and/or braces. I'd like to do this, but as a one-liner from the command line:
12 Answers
...
Why is setTimeout(fn, 0) sometimes useful?
... recently run into a rather nasty bug, wherein the code was loading a <select> dynamically via JavaScript. This dynamically loaded <select> had a pre-selected value. In IE6, we already had code to fix the selected <option> , because sometimes the <select> 's selected...
Nexus 7 not visible over USB via “adb devices” from Windows 7 x64
...he Nexus, or undoubtedly any other device. Not exactly obvious, but if you select the second option "Camera (PTP)" the device is available for debugging (the lesson is ignore the camera, and focus on the protocol PTP).
This configuration is persistent, and I'm guessing that with a brand new device...
Run all SQL files in a directory
...o and make sure SQLCMD Mode is enabled
Click on SQLCMD Mode; files will be selected in grey as below
:r c:\Scripts\script1.sql
:r c:\Scripts\script2.sql
:r c:\Scripts\script3.sql
Now execute
share
|
...