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mysql create user if not exists
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In 5.7.6 and above, you should be able to use CREATE USER
CREATE USER IF NOT EXISTS 'user'@'localhost' IDENTIFIED BY 'password';
Note that the 5.7.6 method doesn't actually grant any permissions.
If you aren't using a version which h...
MySQL InnoDB not releasing disk space after deleting data rows from table
I have one MySQL table using the InnoDB storage engine; it contains about 2M data rows. When I deleted data rows from the table, it did not release allocated disk space. Nor did the size of the ibdata1 file reduce after running the optimize table command.
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How does one reorder columns in a data frame?
...ws, and the 1,2,3,4 refers to the columns.
To change the order as in the above question do df2[,c(1,3,2,4)]
If you want to output this file as a csv, do write.csv(df2, file="somedf.csv")
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How to simulate a mouse click using JavaScript?
I know about the document.form.button.click() method. However, I'd like to know how to simulate the onclick event.
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What is the difference between the different methods of putting JavaScript code in an ?
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I quite enjoy Matt Kruse's Javascript Best Practices article. In it, he states that using the href section to execute JavaScript code is a bad idea. Even though you have stated that your users must have JavaScript enabled, there's no reason you can't have a sim...
SQL Server: What is the difference between CROSS JOIN and FULL OUTER JOIN?
What is the difference between CROSS JOIN and FULL OUTER JOIN in SQL Server?
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Find a pair of elements from an array whose sum equals a given number
Given array of n integers and given a number X, find all the unique pairs of elements (a,b), whose summation is equal to X.
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How do you compare structs for equality in C?
...ties to do this - you have to do it yourself and compare each structure member by member.
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Objective-C : BOOL vs bool
I saw the "new type" BOOL ( YES , NO ).
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When do we need curly braces around shell variables?
In shell scripts, when do we use {} when expanding variables?
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