我脑子里有SQL,会而且应该在1秒之内运行:
SELECT mem.`epid`,
mem.`model_id`,
em.`UKM_Make`,
em.`UKM_Model`,
em.`UKM_CCM`,
em.`UKM_Submodel`,
em.`Year`,
em.`UKM_StreetName`,
f.`fit_part_number`
FROM `table_one` AS mem
INNER JOIN `table_two` em ON mem.`epid` = em.`ePID`
INNER JOIN `table_three` f ON `mem`.`model_id` = f.`fit_model_id`
LIMIT 1;
INNER JOIN `table_three` f ON `mem`.`model_id` = f.`fit_model_id`
以下是我的表格结构:
表1
+----------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+---------+------+-----+---------+-------+
| epid | int(11) | YES | | NULL | |
| model_id | int(11) | YES | | NULL | |
+----------+---------+------+-----+---------+-------+
表2
+----------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------------+--------------+------+-----+---------+-------+
| id | int(11) | NO | PRI | NULL | |
| ePID | int(11) | NO | | NULL | |
| UKM_Make | varchar(100) | NO | | NULL | |
| UKM_Model | varchar(100) | NO | | NULL | |
| UKM_CCM | int(11) | NO | | NULL | |
| UKM_Submodel | varchar(100) | NO | | NULL | |
| Year | int(11) | NO | | NULL | |
| UKM_StreetName | varchar(100) | NO | | NULL | |
| Vehicle Type | varchar(100) | NO | | NULL | |
+----------------+--------------+------+-----+---------+-------+
表3
+-----------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------+-------------+------+-----+---------+----------------+
| fit_fitment_id | int(11) | NO | PRI | NULL | auto_increment |
| fit_part_number | varchar(50) | NO | | NULL | |
| fit_model_id | int(11) | YES | | NULL | |
| fit_year_start | varchar(4) | YES | | NULL | |
| fit_year_end | varchar(4) | YES | | NULL | |
+-----------------+-------------+------+-----+---------+----------------+
以上是
describe $table_name
有什么我明显遗漏的吗?如果没有,我怎么能找出原因
table_three
编辑一个:
CREATE INDEX fit_model ON table_three (fit_model_id)
,它在0.00秒内执行查询(在MYSQL中)。取消限制后,仍在运行的建议。。。所以不太清楚。安东关于使用EXPLAIN的建议我使用了它并得到了以下结果:
+------+-------------+-------+------+---------------+-----------+---------+----------------------+-------+-------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+-------------+-------+------+---------------+-----------+---------+----------------------+-------+-------------------------------------------------+
| 1 | SIMPLE | mem | ALL | NULL | NULL | NULL | NULL | 5587 | Using where |
| 1 | SIMPLE | f | ref | fit_model | fit_model | 5 | mastern.mem.model_id | 14 | |
| 1 | SIMPLE | em | ALL | NULL | NULL | NULL | NULL | 36773 | Using where; Using join buffer (flat, BNL join) |
+------+-------------+-------+------+---------------+-----------+---------+----------------------+-------+-------------------------------------------------+
编辑两个
我使用以下查询根据建议添加了一个外键:
ALTER TABLE `table_one`
ADD CONSTRAINT `model_id_fk_tbl_three`
FOREIGN KEY (`model_id`)
REFERENCES `table_three` (`fit_model_id`)
MYSQL仍然在执行这个命令—有很多行,所以有一半的人希望出现这种行为。有了PHP,我可以像那样分解查询并构建数组,所以我想这可能解决了这个问题——我想我还能做些什么来减少执行时间吗?
