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COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
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Use either COUNT(field) or COUNT(*), and stick with it consistently, and if your database allows COUNT(tableHere) or COUNT(tableHere.*), use that.
In short, don't use COUNT(1) for anything. It's a one-trick pony, which rarely does what you want, and in those rare cases is equivalent to count(*)...
How to disable GCC warnings for a few lines of code
...of the diagnostics as of each push, and restore to that point at each pop. If a pop has no matching push, the command-line options are restored." -- from the GCC manual: gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html
– bobpaul
Jan 11 '13 at 18:43
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Creating a segue programmatically
...ime that creates them for you. You can normally call performSegueWithIdentifier: in your view controller's code, but this relies on having a segue already set up in the storyboard to reference.
What I think you are asking though is how you can create a method in your common view controller (base c...
Select values from XML field in SQL Server 2008
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You must use .nodes() and cross apply if xmlField contains more than one <person> elements.
– Remus Rusanu
May 22 '09 at 18:45
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Inserting HTML into a div
I am trying to insert a chunk of HTML into a div. I want to see if plain JavaScript way is faster than using jQuery. Unfortunately, I forgot how to do it the 'old' way. :P
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R command for setting working directory to source file location in Rstudio
I am working out some tutorials in R. Each R code is contained in a specific folder. There are data files and other files in there. I want to open the .r file and source it such that I do not have to change the working directory in Rstudio as shown below:
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Get value from hidden field using jQuery
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@Jean: I don't undertand that, please be more specific.
– Sarfraz
Jun 22 '10 at 8:55
Please c...
CocoaPods - use specific pod version
.... Of course, this needs to be done from your project's top level folder. If the update does not occur, edit your Podfile.lock file and change the AFNetworking version # to something less than what it is and issue a pod update in the terminal again. This tells CocoaPods that you have a different v...
Download and open PDF file using Ajax
...You don't necessarily need Ajax for this. Just an <a> link is enough if you set the content-disposition to attachment in the server side code. This way the parent page will just stay open, if that was your major concern (why would you unnecessarily have chosen Ajax for this otherwise?). Beside...
Counting the number of elements with the values of x in a vector
...bset it:
> a[names(a)==435]
435
3
Or convert it into a data.frame if you're more comfortable working with that:
> as.data.frame(table(numbers))
numbers Freq
1 4 2
2 5 1
3 23 2
4 34 2
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