R data tricks : merging and joining

rbind and cbind join files respectively as if they were stacked on top of each other - bind by row - and as if they were placed side by side - bind by column.

merge allows you to join datasets on shared columns. remember to specify by = list of fields on which to join, and all=TRUE if you want to include rows in which no union took place.

output CSV from mysql

1. Make sure you've got FILE permission

mysql> grant FILE on *.* to matt;

2. make sure mysql can write to the destination directory - I used /tmp

mysql> select 'hello world' into outfile '/tmp/destination.txt';

3. select your csv output

SELECT order_id,product_name,qty
FROM orders
INTO OUTFILE '/tmp/destination.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n';

restoring a mysql db from file

restoring a mysql db from file

mysql> create database charm;

$ mysql -u matt -D charm -p < charm.sql

mysql> grant all on charm.* to matt;