-- Wanna export a joined result?
SELECT a.id, a.name, b.name
FROM tableA a
JOIN tableB b ON a.id = b.rel_id
WHERE a.deleted=0 and b.deleted=0
ORDER BY a.name, b.nane
INTO OUTFILE '/var/lib/mysql-files/xxxx.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n';


-- Trouble shooting #1
-- User needs to have the FILE grant
mysql> show grants for <user>
-- If it's missing, then grant it
mysql> GRANT FILE ON *.* TO

-- Trouble shooting #2
-- Output path strict?
mysql> SHOW VARIABLES LIKE "secure_file_priv";
+------------------+-----------------------+
| Variable_name    | Value                 |
+------------------+-----------------------+
| secure_file_priv | /var/lib/mysql-files/ |
+------------------+-----------------------+