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MySQL select where column is not empty
In MySQL, can I select columns only where something exists?
13 Answers
13
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typedef fixed length array
I have to define a 24-bit data type.I am using char[3] to represent the type. Can I typedef char[3] to type24 ? I tried it in a code sample. I put typedef char[3] type24; in my header file. The compiler did not complain about it. But when I defined a function void foo(type24 val) {} in my C...
What is the difference between _tmain() and main() in C++?
...point.
It has one of these two signatures:
int main();
int main(int argc, char* argv[]);
Microsoft has added a wmain which replaces the second signature with this:
int wmain(int argc, wchar_t* argv[]);
And then, to make it easier to switch between Unicode (UTF-16) and their multibyte character...
Unicode Processing in C++
...ng new projects in Dev Studio, religiously make sure the Unicode option is selected in your project properties.
For C++ strings, use std::wstring instead of std::string
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Is there a difference between single and double quotes in Java?
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Use single quotes for literal chars, double quotes for literal Strings, like so:
char c = 'a';
String s = "hello";
They cannot be used any other way around (like in Python, for example).
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How can I indent multiple lines in Xcode?
When I select multiple lines of code and want to indent them as usual with TAB key, it just deletes them all. I come from Eclipse where I always did it that way. How's that done in Xcode? I hope not line by line ;)
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Set a persistent environment variable from cmd.exe
... value)
Dim wu
Set wu = wsh.Environment(typey)
wui = wu.Item(vary)
Select Case action
Case "ls"
WScript.Echo wui
Case "del"
On Error Resume Next
wu.remove(vary)
On Error Goto 0
Case "set"
wu.Item(vary) = value
Case "add"
If wui = "" Then
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Vim: How to insert in visual block mode?
...
Try this
After selecting a block of text, press Shift+i or capital I.
Lowercase i will not work.
Then type the things you want and finally to apply it to all lines, press Esc twice.
If this doesn't work...
Check if you have +visualextra ...
#define macro for debug printing in C?
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#include <stdarg.h>
#include <stdio.h>
void dbg_printf(const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
vfprintf(stderr, fmt, args);
va_end(args);
}
You can also use this technique in C99, of course, but the __VA_ARGS__ technique is neater because it uses re...
How to make an OpenGL rendering context with transparent background?
... 0);
assert(hbmpDIB);
assert(bmp_cnt);
if(hbmpDIB)
SelectObject(pdcDIB, hbmpDIB);
}
BOOL CreateHGLRC()
{
DWORD dwFlags = PFD_SUPPORT_OPENGL | PFD_DRAW_TO_BITMAP;
PIXELFORMATDESCRIPTOR pfd ;
memset(&pfd,0, sizeof(PIXELFORMATDESCRIPTOR)) ;
pfd.nSize = size...