php - Mysql 查询执行时间过长

Question

所以我必须表，products_used 大约 600MB 和 products_language_description 大约 5MB，但问题是这个查询永远不会完成运行...

我已经尝试过修复、优化分析，但我不知道如何改进...

SELECT pu.products_id, count(pu.products_id) as products_count, p.products_name,
pu.time_used FROM products_used pu, products_language_description p
WHERE pu.merchant_id='69'
AND p.products_id=pu.products_id GROUP BY products_id ORDER BY products_count
DESC LIMIT 0, 20



CREATE TABLE `products_used` (
    `products_used_id` INT(15) NOT NULL AUTO_INCREMENT,
    `plans_key` VARCHAR(255) NOT NULL DEFAULT '0',
    `products_id` BIGINT(20) NOT NULL DEFAULT '0',
    `customers_id` INT(10) NOT NULL DEFAULT '0',
    `merchant_id` INT(10) NOT NULL DEFAULT '0',
    `time_used` DATETIME NOT NULL DEFAULT '0000-00-00 00:00:00',
    PRIMARY KEY (`products_used_id`),
    INDEX `plans_key` (`plans_key`)
)
COLLATE='latin1_swedish_ci'
ENGINE=MyISAM
AUTO_INCREMENT=24625441;

CREATE TABLE `products_language_description` (
    `products_id` INT(5) NOT NULL DEFAULT '0',
    `products_description` LONGTEXT NOT NULL,
    `products_name` TEXT NOT NULL COLLATE 'utf8_general_ci',
    `products_help_info` LONGBLOB NOT NULL,
    `products_language` VARCHAR(255) NOT NULL DEFAULT '',
    PRIMARY KEY (`products_id`, `products_language`)
)
COLLATE='latin1_swedish_ci'
ENGINE=MyISAM;

Answer 1

尝试向 products_used 表上的 product_id 和 merchant_id 字段添加索引