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MySQL: Invalid use of group function
..., not WHERE.
The difference is: the WHERE clause filters which rows MySQL selects. Then MySQL groups the rows together and aggregates the numbers for your COUNT function.
HAVING is like WHERE, only it happens after the COUNT value has been computed, so it'll work as you expect. Rewrite your subque...
What's the @ in front of a string in C#?
...also allows multi-line contents - which can be very handy for SQL:
string select = @"
SELECT Foo
FROM Bar
WHERE Name='Baz'";
The one bit of escaping which is necessary for verbatim string literals is to get a double quote (") which you do by doubling it:
string verbatim = @"He said, ""Would you ...
Making the Android emulator run faster
...ve to properly shut down your emulator device (hold the power button, then select Power off) to avoid having errors when you start it the next time (I could just close the ARM emulator, but with the Intel emulator, just closing seems to create problems).
– ADTC
...
Get button click inside UITableViewCell
... action for your button as below:
[cell.yourbutton addTarget:self action:@selector(yourButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
3) Code actions based on index as below in ViewControler:
-(void)yourButtonClicked:(UIButton*)sender
{
if (sender.tag == 0)
{
...
How to remove unused imports from Eclipse
...rences → Java → Editor → Save Actions.
Check the option "Perform the selected actions on save".
Check the option "Organize imports".
Now every time you save your classes, eclipse will take care of removing the unused imports.
...
Hidden features of Perl?
...
One of my favourite features in Perl is using the boolean || operator to select between a set of choices.
$x = $a || $b;
# $x = $a, if $a is true.
# $x = $b, otherwise
This means one can write:
$x = $a || $b || $c || 0;
to take the first true value from $a, $b, and $c, or a default of 0...
:first-child not working as expected
I'm trying to select the first h1 inside a div with a class called detail_container . It works if h1 is the first element within this div , but if it comes after this ul it won't work.
...
Procedure expects parameter which was not supplied
... data tab [beside layout and Preview tabs] next to the name of the dataset selected, there is another drop down control that lets you change the CommandType. Enjoy!
– SarjanWebDev
Aug 14 '12 at 6:17
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Tricks to manage the available memory in an R session
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I make aggressive use of the subset parameter with selection of only the required variables when passing dataframes to the data= argument of regression functions. It does result in some errors if I forget to add variables to both the formula and the select= vector, but it sti...
Is there a way to suppress warnings in Xcode?
... Easy way to get the warning code: go to the Log Navigator (Command+7), select the topmost build, expand the log (the '=' button on the right), and scroll to the bottom.
– Neal Ehardt
Jan 25 '12 at 16:46
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