How to retrieve data from table with join - mysql

Question

I'm using MySQL 5.5. with two tables in it:
DROP TABLE IF EXISTS `events_dictionary`;
CREATE TABLE `events_dictionary` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(64) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `events_dictionary` VALUES (1, 'Light'),(2, 'Switch'),(3, 'on'),(4, 'off');
DROP TABLE IF EXISTS `events_log`;
CREATE TABLE `events_log` (
`log_id` bigint(20) NOT NULL AUTO_INCREMENT,
`event_name_id` int(11) NOT NULL DEFAULT '0',
`event_param1` int(11) DEFAULT NULL,
`event_value1` int(11) DEFAULT NULL,
PRIMARY KEY (`log_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `events_log` VALUES (1, 1, 2, 3),(2, 1, 2, 4);
Table events_dictionary contains names for events_log events names,params and values.
So, my question is - how could i select data from event_log table with columns event_name_id, event_param1, event_value1 mapped to name values from events_dictionary table?
I tried to do this query:
SELECT name, event_param1, event_value1
FROM events_log
JOIN events_dictionary ON events_log.event_name_id = events_dictionary.id;
But, in this case i see only event_name_id replaced with values from events_dictionary, like this:
name | event_param1 | event_value1
Light | 1 | 1
Light | 1 | 2
And i want to replace event_param1, and event_value1 with names from events_dictionary too.
Thanks in advance!

Answer 1

You need to join to the events_dictionary multiple times
SELECT a.name, b.name, c.name
FROM events_log
JOIN events_dictionary a ON events_log.event_name_id = a.id
JOIN events_dictionary b ON events_log.event_param1 = b.id
JOIN events_dictionary c ON events_log.event_value1 = c.id;
PS
Your example for the event_log isn't that helpful , instead insert the values (1,1,2,3),(2,1,2,4) to turn the switch on and off for the light.
DS

Answer 2

You can use correlated subqueries:
SELECT name,
(SELECT t.name
FROM events_dictionary AS t
WHERE t.id = event_param1) AS param_name,
(SELECT t2.name
FROM events_dictionary AS t2
WHERE t2.id = event_value1) AS event_name
FROM events_log AS el
JOIN events_dictionary AS ed ON el.event_name_id = ed.id;
Demo here