这是我的查询，在远程MySQL服务器上执行至少需要1分钟。
select
a.z_companyid_pk 'z_companyid_pk',
a.company_name 'Client',
a.display_name 'Display_Name',
a.z_parentcompanyid_fk 'Parent_Company',
a.z_resellerid_fk 'Reseller',
(select
company_name
from
company_mst
where
z_companyid_pk = a.z_resellerid_fk) 'Reseller_name',
(select
if(count(*) >= 1, 'YES', 'NO')
from
webprofile
where
z_boxid_fk in (select
z_boxid_pk
from
box_mst
where
z_companyid_fk = a.z_companyid_pk)) 'V1_Website',
(select
if(count(*) >= 1, 'YES', 'NO')
from
webapp_mst
where
z_companyid_fk = a.z_companyid_pk) 'V2_Website',
(select
if(count(*) > 0, 'YES', 'NO')
from
widget_mst
where
widget_status = 1
and type in ('templated-menu' , 'menus')
and z_companyid_fk = a.z_companyid_pk) 'Widgets_with_my_menu',
(select
if(count(imagehtml) > 0, 'YES', 'NO')
from
image_mst
where
length(imagehtml) > 0
and z_companyid_fk = a.z_companyid_pk) 'HTML_menus',
(select
max(login_datetime)
from
loginlog_mst a
LEFT OUTER JOIN
contact_mst b ON a.z_contactid_fk = b.z_contactid_pk
where
b.z_companyid_fk = a.z_companyid_pk) 'LCI',
k.z_boxid_pk 'DMB_Box_ID',
k.box_name,
(select
box_lastcheck
from
box_online
where
z_boxid_fk = k.z_boxid_pk) 'LCI_last_Checked_in_Date',
(select
websitelink
from
company_profile
where
z_companyid_fk = a.z_companyid_pk) 'Website',
(select
company_email
from
company_profile
where
z_companyid_fk = a.z_companyid_pk) 'Primary_Contact_Email',
concat(a.company_address_line1,
a.company_address_line2) 'address',
(select
city_name
from
city_mst
WHERE
z_cityid_pk = a.z_cityid_fk) 'city',
(select
state_name
from
state_mst
WHERE
z_stateid_pk = a.z_stateid_fk) 'Province',
(select
country_name
FROM
country_mst
where
z_countryid_pk = z_countryid_fk) 'country_name',
a.company_postalcode 'zip_postal_code',
(select
telephone
from
company_profile
where
z_companyid_fk = a.z_companyid_pk) 'company_telephone',
a.z_timezoneid_fk,
b.timezone 'time_Zone',
(select
facebooklink
from
company_profile
where
z_companyid_fk = a.z_companyid_pk) 'facebook',
(select
twitterlink
from
company_profile
where
z_companyid_fk = a.z_companyid_pk) 'twitter',
(SELECT
bizurl
FROM
user_settings us
INNER JOIN
asset_mst am ON (us.userid = am.userid)
where
us.isiteid = 1
and am.z_companyid_fk = a.z_companyid_pk) 'Yelp',
(SELECT
bizurl
FROM
user_settings us
INNER JOIN
asset_mst am ON (us.userid = am.userid)
where
us.isiteid = 2
and am.z_companyid_fk = a.z_companyid_pk) 'Urbanspoon',
(SELECT
bizurl
FROM
user_settings us
INNER JOIN
asset_mst am ON (us.userid = am.userid)
where
us.isiteid = 3
and am.z_companyid_fk = a.z_companyid_pk) 'Trip_Advisor',
(SELECT
bizurl
FROM
user_settings us
INNER JOIN
asset_mst am ON (us.userid = am.userid)
where
us.isiteid = 4
and am.z_companyid_fk = a.z_companyid_pk) 'Citysearch',
(SELECT
bizurl
FROM
user_settings us
INNER JOIN
asset_mst am ON (us.userid = am.userid)
where
us.isiteid = 5
and am.z_companyid_fk = a.z_companyid_pk) 'Open_Table',
(SELECT
bizurl
FROM
user_settings us
INNER JOIN
asset_mst am ON (us.userid = am.userid)
where
us.isiteid = 6
and am.z_companyid_fk = a.z_companyid_pk) 'ZAGAT',
(SELECT
bizurl
FROM
user_settings us
INNER JOIN
asset_mst am ON (us.userid = am.userid)
where
us.isiteid = 32
and am.z_companyid_fk = a.z_companyid_pk) 'Zomato',
d.z_contactid_fk 'Email_contact_ID',
d.username 'Email_User_Name',
d.contact_firstname,
d.contact_lastname,
d.status,
(select
max(login_datetime)
from
loginlog_mst
where
z_contactid_fk = d.z_contactid_fk) 'last_login_date',
(select
GROUP_CONCAT(groupname)
from
contact_group_mst
where
z_companyid_fk = a.z_companyid_pk) 'group_name'
from
company_mst a
LEFT OUTER JOIN
timezone_mst b ON a.z_timezoneid_fk = b.z_timezoneid_pk
LEFT OUTER JOIN
company_profile c ON a.z_companyid_pk = c.z_companyid_fk
LEFT OUTER JOIN
(select
v.z_contactid_fk,
v.z_companyid_fk,
w.username,
w.contact_firstname,
w.contact_lastname,
if(contact_wtaccess = 1, 'Veryfied', 'Not Veryfied') 'status'
from
priviledge_mst v
LEFT OUTER JOIN contact_mst w ON v.z_contactid_fk = w.z_contactid_pk
where
w.type <> 'Staff') d ON a.z_companyid_pk = d.z_companyid_fk
LEFT OUTER JOIN
(select
z_boxid_pk, box_name, asset_mst.z_companyid_fk
from
box_mst
INNER JOIN asset_mst ON (box_mst.userid_fk = asset_mst.userid)
where
asset_mst.status = 0
and type = 'menubox') k ON a.z_companyid_pk = k.z_companyid_fk
where
a.status <> 0
and a.z_companyid_pk in (101089 , 104001, 103863)
ORDER BY a.company_name
请通过推荐一些技巧或修改或我可以应用于此查询以提高性能的任何提示来帮助我。
答案 0 :(得分：0)
即使没有实际数据，也很难确定实际问题。但你可以用以下2种方法检查 -
您在左连接中使用子查询，在子查询中传递z_companyid_pk以减少子查询中的数据集。
删除子查询并简单地使用左连接。
假设您已经检查过并且所有必需的索引都在那里。
答案 1 :(得分：0)
构造
JOIN ( SELECT ... )
JOIN ( SELECT ... )
执行效果不佳，因为这些子查询的tmp表中没有索引。如果可能，将它们转换为表格的JOIN。如果没有，则为它们创建TEMATEARY TABLE并索引tmp表。
a需要INDEX(z_companyid_pk)，除非该列已经是PRIMARY KEY。
输出中有多少行？我想了解聚合需要做多少工作。
请勿使用LEFT，除非您希望并希望“右”表中缺少数据。
和type ='menubox'
哪个表格是type？
请为priviledge_mst，contact_mst，company_mst，asset_mst，box_mst提供SHOW CREATE TABLE。我们需要检查索引。