пятница, 2 октября 2009 г.

Отличный пример работы с sed(выгрузка данных из mysql в csv)

на всякий пожарный цитирую тут:

Export from MySQL to CSV

Using command line tools to export data from a MySQL database into a CSV file is quite easy. Here's how:

mysql -uexampleuser -pletmein exampledb -B -e "select * from \`person\`;" | sed 's/\t/","/g;s/^/"/;s/$/"/;s/\n//g' > filename.csv

Here is some sample output of the above:

"id","username","group","password"
"1","tux","admin","5f4dcc3b5aa765d61d8327deb882cf99"
"2","tlugian","admin","5f4dcc3b5aa765d61d8327deb882cf99"
"3","saiyuki","admin","5f4dcc3b5aa765d61d8327deb882cf99"
"4","fred","staff","5f4dcc3b5aa765d61d8327deb882cf99"
"5","barney","staff","5f4dcc3b5aa765d61d8327deb882cf99"
"6","wilma","admin","5f4dcc3b5aa765d61d8327deb882cf99"

And now for the explanation:

Starting with the MySQL command. I wont explain the -u and -p options they are straight forward (if in doubt man mysql). The -B option will delimit the data using tabs and each row will appear on a new line. The -e option denotes the command to run once you have logged into the database. In this case we are using a simple SELECT statement.

Onto sed. The command used here contains three seperate sed scripts:

s/\t/","/g;s/^/"/ <--- this will search and replace all occurences of 'tabs' and replace them with a ",".

;s/$/"/; <--- This will place a " at the start of the line.

s/\n//g <---- This will place a " at the end of the line.

After running the result set through sed we redirect the output to a file with a .csv extension.


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