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How to concatenate columns in a Postgres SELECT?
...catenated to NULL is NULL. If NULL values can be involved and the result shall not be NULL, use concat_ws() to concatenate any number of values (Postgres 9.1 or later):
SELECT concat_ws(', ', a, b) AS ab FROM foo;
Or concat() if you don't need separators:
SELECT concat(a, b) AS ab FROM foo;
No...
How is the java memory pool divided?
...ap memory
The heap memory is the runtime data area from which the Java VM allocates memory for all class instances and arrays. The heap may be of a fixed or variable size. The garbage collector is an automatic memory management system that reclaims heap memory for objects.
Eden Space: The pool fr...
How to check file MIME type with javascript before upload?
...emo at the bottom.
Check that your browser supports both File and Blob. All major ones should.
if (window.FileReader && window.Blob) {
// All the File APIs are supported.
} else {
// File and Blob are not supported
}
Step 1:
You can retrieve the File information from an <in...
How to compile a 64-bit application using Visual C++ 2010 Express?
...
Here are step by step instructions:
Download and install the Windows Software Development Kit version 7.1. Visual C++ 2010 Express does not include a 64 bit compiler, but the SDK does. A link to the SDK: http://msdn.microsoft.com/en-us/windowsserver/bb980924.aspx
Change your pr...
How to check if APK is signed or “debug build”?
... java.security.cert.CertificateException and android.content.pm.Signature. All other classes don't present multiple matches for me
– Christian García
Nov 29 '12 at 13:55
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SQL - many-to-many table primary key
...at the table sorted, just the index. And the index won't be stored sequentially, it'll be stored in an efficient manner to be able to be retrieved quickly.
In addition, the vast majority of database tables are read far more often than written. That makes anything you do on the select side far more ...
How can I set multiple CSS styles in JavaScript?
...s repainting the element every time you change a property (you change them all "at once" somehow).
On the other side, you would have to build the string first.
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why windows 7 task scheduler task fails with error 2147942667
...ks fail to run if the path in "Start in (Optional)" field has quotes
Basically, edit your scheduled task and take the Quotes out of the Start In field:
Open your Scheduled Task
Switch to "Actions" tab
Open your Action
Remove Quotes (") from the field "Start in (optional)"
Save and close all open ...
Convert String to Float in Swift
...ying to convert numbers taken from a UITextField, which I presume, are actually Strings, and convert them to Float, so I can multiply them.
...
Detect network connection type on Android
...twork is connected and fast enough to meet your demands you have to handle all the network types returned by getSubType().
It took me an hour or two to research and write this class to do just exactly that, and I thought I would share it with others that might find it useful.
Here is a Gist of the...