Mysql

SELECT a,b,a+b INTO OUTFILE '/tmp/result.txt'
 FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
 LINES TERMINATED BY '\n'
 FROM test_table;

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

USE mysql;
UPDATE user SET File_priv = 'Y' WHERE User = 'db_user';
FLUSH PRIVILEGES;