MySQL error

This is a small error, but I was scared when I saw it. For convenience, I switched the owner of “/usr/local/” into my current account.

sudo chown -R user:group /usr/local/

It made MySQL can not read the table content!! So never change the owner of “/usr/local/mysql” if you know what will happen.

Update wordpress without usingFTP

Edit the “wp-content.php” file as follow:

/** Set up direct method for wordpress update without using FTP */
define('FS_METHOD','direct');

These sentences are preferred to plug into the last part of wp-content.php.

R: Linear Least Squares Regression

Here we look at the most basic linear least squares regression. The main purpose is to provide an example of the basic commands. It is assumed that you know how to enter data or read data files which is covered in the first chapter, and it is assumed that you are familiar with the different data types.

We will examine the interest rate for four year car loans, and the data that we use comes from the U.S. Federal Reserve’s mean rates. We are looking at and plotting means. This, of course, is a very bad thing because it removes a lot of the variance and is misleading. The only reason that we are working with the data in this way is to provide an example of linear regression that does not use too many data points. Do not try this without a professional near you, and if a professional is not near you do not tell anybody you did this. They will laugh at you. People are mean, especially professionals.
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SQLite3

  1. Get the row numbers after group or select the query.
    select count(*) as rows from (select * from database group by query)