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How to 'insert if not exists' in MySQL?
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Solution:
INSERT INTO `table` (`value1`, `value2`)
SELECT 'stuff for value1', 'stuff for value2' FROM DUAL
WHERE NOT EXISTS (SELECT * FROM `table`
WHERE `value1`='stuff for value1' AND `value2`='stuff for value2' LIMIT 1)
Explanation:
The innermost query
SELECT *...
How to integrate CSS pre-processing within Eclipse? [closed]
...and then click OK.
Find the *.scss entry in the File Associations list and select it.
After selecting *.scss, on the bottom pane Associated editors:, click the Add... button.
Make sure Internal editors is selected on the top, then find and select CSS Editor and then click OK.
This associated the f...
“A project with an Output type of Class Library cannot be started directly”
...oject in Solution Explorer -> Properties.
In opened tab with properties select Application and there will be ComboBox marked with Output Type label.
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How does Facebook Sharer select Images and other metadata when sharing my URL?
...s pulled from the source as a preview for their link. How are these images selected, and how can I ensure that any particular image on my page is always included in this list?
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“Inspect” a hover element?
...if this is just a problem on my PC or not, but I can't see the menu option selected via keyboard and the shortcut key (ctrl-shift-I) doesn't work while the dropdown menu is visible, so since inspect element is the last option on the dropdown, I used up-arrow key to wrap-around to the last item and h...
Select rows of a matrix that meet a condition
...20, ncol = 4)
colnames(m) <- letters[1:4]
The following command will select the first row of the matrix above.
subset(m, m[,4] == 16)
And this will select the last three.
subset(m, m[,4] > 17)
The result will be a matrix in both cases.
If you want to use column names to select columns...
How can I resolve “Error: No developer directory found at /Developer”?
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sudo xcode-select -switch /Applications/Xcode.app/Contents/Developer
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Selecting pandas column by location
...ed in future versions. See pandas.pydata.org/pandas-docs/dev/… on how to select by position using iloc/iat.
– Wouter Overmeire
Apr 12 '13 at 10:04
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CSS selector - element with a given child [duplicate]
I'm looking to make a selector which will select all elements if they have a specific child element. For example, select all <div> with a child <span> .
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Get spinner selected items text?
How to get spinner selected item's text?
13 Answers
13
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