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How to filter SQL results in a has-many-through relation
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Results:
Total runtimes from EXPLAIN ANALYZE.
1) Martin 2: 44.594 ms
SELECT s.stud_id, s.name
FROM student s
JOIN student_club sc USING (stud_id)
WHERE sc.club_id IN (30, 50)
GROUP BY 1,2
HAVING COUNT(*) > 1;
2) Erwin 1: 33.217 ms
SELECT s.stud_id, s.name
FROM student s
JOIN ...
How to hide a in a menu with CSS?
...hat Chrome, it seems, will not allow me to hide <option> in a <select> . Firefox will.
13 Answers
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Real life example, when to use OUTER / CROSS APPLY in SQL
...1) Top N per group queries (can be more efficient for some cardinalities)
SELECT pr.name,
pa.name
FROM sys.procedures pr
OUTER APPLY (SELECT TOP 2 *
FROM sys.parameters pa
WHERE pa.object_id = pr.object_id
ORDER BY pr.n...
How do you remove all the options of a select box and then add one option and select it with jQuery?
Using core jQuery, how do you remove all the options of a select box, then add one option and select it?
24 Answers
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select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
select、poll、epoll之间的区别总结[整理]select，poll，epoll都是IO多路复用的机制。I O多路复用就通过一种机制，可以监视多个描述符，一旦某个描述符就绪（一般是读就绪或者写就绪...select，poll，epoll都是IO多路复用的机制。I/O多路...
How to add extra info to copied web text
...cument.location.href}`;
event.clipboardData.setData('text', document.getSelection() + pagelink);
event.preventDefault();
});
Lorem ipsum dolor sit amet, consectetur adipiscing elit.<br/>
<textarea name="textarea" rows="7" cols="50" placeholder="paste your copied text here"></...
UIButton: set image for selected-highlighted state
I set an images for button's states Normal,Highlighted and Selected, but when the button in selected state and I press/highlight it I didn't see my highlighted image but just grayed picture.
Is it possible to set an image for highlighted state when the button selected?
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quick random row selection in Postgres
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You might want to experiment with OFFSET, as in
SELECT myid FROM mytable OFFSET floor(random()*N) LIMIT 1;
The N is the number of rows in mytable. You may need to first do a SELECT COUNT(*) to figure out the value of N.
Update (by Antony Hatchkins)
You must use floor he...
How to make an Android Spinner with initial text “Select One”?
I want to use a Spinner that initially (when the user has not made a selection yet) displays the text "Select One". When the user clicks the spinner, the list of items is displayed and the user selects one of the options. After the user has made a selection, the selected item is displayed in the Spi...
How do I replace text in a selection?
...e you have open.
There is an icon option which when hovered over says "In Selection" that you can select to find and replace within a selection. I've pointed to the correct icon in the screenshot below.
Hit replace all, and voila, all instances of '0' will be replaced with '255'.
Note: this ...