How can I select distinct column based on max datetime (another column) also joining two tables in MySQL?

Question

I've read many somewhat similar questions here and tried everything I can think of, without success. I think I've found the question based on a single table, or without the need for getting a distinct column, but not my situation exactly.

I want to get distinct ticker_symbol and corresponding ticker_name and latest ticker_quote based on these tables:

CREATE TABLE `tickers` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `ticker_symbol` varchar(6) COLLATE utf8_unicode_ci NOT NULL,
  `ticker_name` varchar(128) COLLATE utf8_unicode_ci NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  `updated_at` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci



CREATE TABLE `ticker_quotes` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `ticker_symbol` varchar(6) COLLATE utf8_unicode_ci NOT NULL,
  `ticker_quote` float(8,2) NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  `updated_at` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=111 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

Answer 1

Try

SELECT q.ticker_symbol, t.ticker_name, q.ticker_quote
  FROM (SELECT ticker_symbol, MAX(created_at) created_at
          FROM ticker_quotes 
         GROUP BY ticker_symbol) m JOIN
       ticker_quotes q ON m.ticker_symbol = q.ticker_symbol 
                      AND m.created_at = q.created_at JOIN
       tickers t ON q.ticker_symbol = t.ticker_symbol

SQLFiddle