下面的查询会搜索客户之前所做的选择并获得正确的结果。无论如何,查询应该尽可能快。在测试时我意识到where子句会减慢查询速度。我们可以解决这个问题吗?
SELECT
customerselections.customer_id,
customerselections.selectedcompany_id,
companycampaigns.*,
companies.company_logo
FROM customerselections
INNER JOIN companycampaigns ON companycampaigns.company_id=customerselections.selectedcompany_id
INNER JOIN companies ON companies.company_id=customerselections.selectedcompany_id
WHERE customerselections.customer_id='$customerid' LIMIT $offset,$limit
更新:解释结果
客户选择:
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE customerselections ALL NULL NULL NULL NULL 12799999
companycampaigns
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE companycampaigns ALL NULL NULL NULL NULL 2000000
公司
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE companies ALL NULL NULL NULL NULL 2039500
QUERY EXPLAIN
|id|select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
|1|SIMPLE | customerselections | ref | selectedcompany_id,customer_id | customer_id | 4 | const | 2 9 | |
|1|SIMPLE| companycampaigns | ref | company_id | company_id | 4 | viptrio.customerselections.selectedcompany_id | 1 | |
|1|SIMPLE| companies | eq_ref | PRIMARY | PRIMARY | 4 | viptrio.customerselections.selectedcompany_id |1 | |
更新
CREATE TABLE IF NOT EXISTS `companies` (
`company_id` int(11) NOT NULL auto_increment,
`company_customerid` int(11) default NULL,
`company_name` tinytext NOT NULL,
`company_description` tinytext,
`company_email` tinytext NOT NULL,
`company_website` tinytext,
`company_gsm` tinytext,
`company_landline` tinytext,
`company_fax` tinytext,
`company_address` tinytext,
`company_contactperson` tinytext,
`company_businessid` smallint(11) NOT NULL,
`company_cityid` smallint(5) NOT NULL,
`company_countrycode` char(3) NOT NULL,
`company_refnum` tinytext,
`company_regdate` tinytext NOT NULL,
`company_logo` tinytext,
`company_keyword` tinytext,
PRIMARY KEY (`company_id`),
KEY `company_cityid` (`company_cityid`),
KEY `company_countrycode` (`company_countrycode`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=2039501 ;
CREATE TABLE IF NOT EXISTS `companycampaigns` (
`campaign_id` int(11) NOT NULL auto_increment,
`company_id` int(11) NOT NULL,
`campaign_title` varchar(40) NOT NULL,
`campaign_detail` mediumtext NOT NULL,
`campaign_startdate` tinytext,
`campaign_enddate` tinytext,
`published` tinyint(1) NOT NULL default '0',
PRIMARY KEY (`campaign_id`),
KEY `company_id` (`company_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=2000001 ;
CREATE TABLE IF NOT EXISTS `customerselections` (
`selection_id` int(11) NOT NULL auto_increment,
`customer_id` int(11) NOT NULL,
`selectedcompany_id` int(11) NOT NULL,
PRIMARY KEY (`selection_id`),
KEY `selectedcompany_id` (`selectedcompany_id`),
KEY `customer_id` (`customer_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=12800006 ;
答案 0 :(得分:0)
你可以尝试下面的
SELECT * FROM
(SELECT * FROM customerselections WHERE customer_id ='$ customerid')as cs
内联合公司公司cc ON cc.company_id = cs.selectedcompany_id
INNER JOIN公司c ON c.company_id = cs.selectedcompany_id
LIMIT $ offset,$ limit
答案 1 :(得分:0)
试试这个:
SELECT'$ customerid',cc。*,c.logo 从 companycampaigns cc INNER JOIN公司c ON c.company_id = cc.company_id 其中c.company_id in(SELECT selectedcompany_id FROM customerselections FROM customer_id ='$ customerid') LIMIT $ offset,$ limit
答案 2 :(得分:0)
试试这个(带有customer_id的索引):
SELECT t1.customer_id, t1.selectedcompany_id,
cc.*, c.company_logo
FROM (SELECT customer_id, selectedcompany_id,
FROM customerselections
WHERE customer_id='$customerid' ) AS t1
INNER JOIN companycampaigns cc ON cc.company_id = t1.selectedcompany_id
INNER JOIN companies c ON c.company_id = t1.selectedcompany_id
LIMIT $offset, $limit
我更喜欢使用表别名来使查询更具可读性。
答案 3 :(得分:0)
我认为`customerselections`.`customer_id`
是int
,但您正在尝试:
WHERE customerselections.customer_id='$customerid'
将它与字符串进行比较。你试过了吗?
WHERE customerselections.customer_id = $customerid
。