I have one query which almost took 22 second to populate data.
SELECT
TP.*,
GROUP_CONCAT(DISTINCT TS.`subject_name`) AS subjects,
GROUP_CONCAT(DISTINCT TC.`class_name`) AS classes,
GROUP_CONCAT(DISTINCT TT.`tution_name`) AS tution_type,
GROUP_CONCAT(DISTINCT TL.`name`) AS locations
FROM `tutor_profile` TP
LEFT JOIN `tutor_to_subject` TTS ON TP.`tutor_id`=TTS.`tutor`
LEFT JOIN `tutor_subjects` TS ON TS.`subject_id`=TTS.`subject`
LEFT JOIN `tutor_to_class` TTC ON TP.`tutor_id`=TTC.`tutor`
LEFT JOIN `tutor_classes` TC ON TC.`class_id`=TTC.`class`
LEFT JOIN `tutor_to_tution_type` TTTT ON TP.`tutor_id`=TTTT.`tutor`
LEFT JOIN `tution_types` TT ON TT.`tution_id`=TTTT.`tution_type`
LEFT JOIN `tutor_to_locality` TTL ON TP.`tutor_id`=TTL.`tutor`
LEFT JOIN `tutor_locality` TL ON TL.`id`=TTL.`locality`
WHERE 1=1 AND TP.`status` = 1
GROUP BY TP.`tutor_id`
ORDER BY TP.`date_added` DESC LIMIT 0 , 25
is there anyway to improve its performance?
You may try to use correlated subqueries in the output list instead of JOIN and GROUP BY:
SELECT
TP.*,
( SELECT GROUP_CONCAT(DISTINCT TS.`subject_name`)
FROM `tutor_to_subject` TTS
LEFT JOIN `tutor_subjects` TS ON TS.`subject_id`=TTS.`subject`
WHERE TP.`tutor_id`=TTS.`tutor` ) AS subjects,
-- the same for another output columns
FROM `tutor_profile` TP
WHERE 1=1 AND TP.`status` = 1
ORDER BY TP.`date_added` DESC LIMIT 0 , 25
Replace these
GROUP_CONCAT(DISTINCT TS.`subject_name`) AS subjects,
LEFT JOIN `tutor_to_subject` TTS ON TP.`tutor_id`=TTS.`tutor`
LEFT JOIN `tutor_subjects` TS ON TS.`subject_id`=TTS.`subject`
with
( SELECT GROUP_CONCAT(DISTINCT TS.`subject_name`
FROM `tutor_to_subject` TTS
JOIN `tutor_subjects` TS ON TS.`subject_id` = TTS.`subject`
WHERE TP.`tutor_id` = TTS.`tutor`
) AS subjects,
and toss the JOIN for TS. Do likewise for the other 3 group_concat + Left join.
For many-to-many tables, improve the indexes:
CREATE TABLE tutor_to_subject
tutor_id ...,
subject_id ...,
PRIMARY KEY(tutor_id, subject_id),
INDEX(subject_id)
) ENGINE=InnoDB;
More discussion: Many:many mapping
Also, get rid of the GROUP BY since it should not longer be needed.
And add
INDEX(status, date_added)
Related
I try to improve this query but I do not made successefully. I use a some left join and subquerys (I don't know another form) We try to get all bookings from users with certain status and the number of bookings multiples related with this booking and get from the log user the origin. The query is slow even if use a limit clausure. I Appreciate all the help can you give me.
This is the query:
SELECT DISTINCT b.uneaque_id, b.id, b.status, b.route_status, b.username, b.purpose, b.transfer, b.pickup_date, b.pickup_time, b.return_time, b.amount, b.default_location, b.start_address_route_comments, b.start_address_route, b.end_address_route_comments, b.end_address_route, u1.first_name, u1.last_name, b.transaction_Id, b.manual_payment, mr.AddressCount, lu.origin
FROM bookingdetails b
LEFT JOIN log_users lu ON lu.uneaque_id = b.uneaque_id AND lu.command_type = 'NEW BOOKING'
LEFT JOIN (
SELECT booking_id, COUNT(*) AS AddressCount FROM booking_multiple_rides GROUP BY booking_id
) mr ON b.id = mr.booking_id,
userdetails u1 WHERE b.username = u1.email
AND u1.user_status IN ('Active', 'Blocked', 'Not_Active')
AND b.default_location = 1
PD: Sorry for my english.
You have a ON b.id = mr.booking_id, userdetails u1 WHERE
you should change with a proper inner join
SELECT DISTINCT b.uneaque_id
, b.id, b.status
, b.route_status
, b.username
, b.purpose
, b.transfer
, b.pickup_date
, b.pickup_time
, b.return_time
, b.amount
, b.default_location
, b.start_address_route_comments
, b.start_address_route
, b.end_address_route_comments
, b.end_address_route
, u1.first_name
, u1.last_name
, b.transaction_Id
, b.manual_payment
, mr.AddressCount
, lu.origin
FROM bookingdetails b
LEFT JOIN log_users lu ON lu.uneaque_id = b.uneaque_id AND lu.command_type = 'NEW BOOKING'
LEFT JOIN (
SELECT booking_id
, COUNT(*) AS AddressCount
FROM booking_multiple_rides GROUP BY booking_id
) mr ON b.id = mr.booking_id
INNER JOIN userdetails u1 ON b.username = u1.email
AND u1.user_status IN ('Active', 'Blocked', 'Not_Active')
AND b.default_location = 1
and be sure you have proper index on
table bookingdetails a composite index on columns ( uneaque_id , id, default_location)
table log_users a composite index on columns (uneaque_id, command_type)
table userdetails a cmposite index on columns (email,user_status )
Tip 1.
Hiding a derived table in a LEFT JOIN is a prescription for sluggishness.
Replace
mr.AddressCount
with
( SELECT COUNT(*)
FROM booking_multiple_rides
WHERE booking_id = b.id
GROUP BY booking_id ) AS AddressCount
and get rid of the LEFT JOIN ( SELECT ... ) AS mr ON ..
Tip 2 Use explicit JOINs, no the old-fashioned "comma-join":
JOiN userdetails u1
ON b.username = u1.email
This won't help performance but it will make things clearer.
Tip 3: If you need an INNER JOIN (u1) after a LEFT JOIN, use parentheses. Else, put the inner joins first, then the left joins. This makes it easier to use, but may screw up the logic.
Tip 4: Don't use LEFT unless you need it. When you dont need it, it confuses the reader (and the Optimizer). (Again, no performance change.)
Tip 5: Why are you using DISTINCT? That takes an extra pass over all the resultset.
If those do not help enough, then provide SHOW CREATE TABLE so we can critique the indexes.
Good afternoon,
I'm trying to get some information from my MySQL database and I'm having problems because I'm not able to have the information needed. I have tried a lot of different approaches and none of them have worked. I hope you can find something because I'm very close to find the solution but something is missing:
MySQL query:
SELECT b.id, b.tipo_perfil, round(avg(b.edad)), COUNT(c.zona), c.zona
FROM analizador_datos_usuario AS a
INNER JOIN analizador_datos_perfil AS b ON (a.id_usuario = b.id_perfil)
INNER JOIN analizador_datos_perfil_historial AS c ON (b.id = c.id_perfil)
WHERE a.id_usuario=21
GROUP BY b.tipo_perfil, c.zona
ORDER BY b.tipo_perfil ASC, count(c.zona) DESC
This query gives me the following information:
Table (in red it's what I need):
Kind regards,
try that :
SELECT b.tipo_perfil, round(avg(b.edad)), COUNT(distinct c.zona), group_concat(distinct b.id separator ' ') as id_list, group_concat(distinct c.zona separator ' ') as zona_list
FROM analizador_datos_usuario AS a
INNER JOIN analizador_datos_perfil AS b ON (a.id_usuario = b.id_perfil)
INNER JOIN analizador_datos_perfil_historial AS c ON (b.id = c.id_perfil)
WHERE a.id_usuario=21
GROUP BY b.tipo_perfil
ORDER BY b.tipo_perfil ASC, count(distinct c.zona) DESC
I think you are getting result what is displayed and you want result which is in red colour.
Try this modified query:-
SELECT b.id, b.tipo_perfil, round(avg(b.edad)), COUNT(c.zona) counted_zone, c.zona
FROM analizador_datos_usuario AS a
INNER JOIN analizador_datos_perfil AS b ON (a.id_usuario = b.id_perfil)
INNER JOIN analizador_datos_perfil_historial AS c ON (b.id = c.id_perfil)
WHERE a.id_usuario=21
GROUP BY b.tipo_perfil, c.zona
Having MAX(counted_zone)
ORDER BY b.tipo_perfil ASC, counted_zone DESC
I have the below SQL query and it will return a group_name along with a list of departments for that group. I was able to lowercase the departments returned, but I can't figure out how to lowercase the group name as well.
Also, instead of lowercasing each returned column is there perhaps a way to lowercase the entire result in one swoop?
SELECT sg.group_name,A.dept_name
FROM `sys_groups` `sg`
INNER JOIN (SELECT gda.group_id,
GROUP_CONCAT(LOWER(sd.dept_name) ORDER BY `dept_name`
SEPARATOR '|'
) `dept_name`
FROM `group_dept_access` `gda`
INNER JOIN `sys_department` `sd`
ON gda.dept_id = sd.dept_id
GROUP BY gda.group_id) AS `A`
ON sg.group_id = A.group_id
Thank you in advance!
Try this:
SELECT LOWER(sg.group_name) group_name, LOWER(A.dept_name) dept_name
FROM sys_groups sg
INNER JOIN (SELECT gda.group_id,
GROUP_CONCAT(sd.dept_name ORDER BY dept_name SEPARATOR '|') dept_name
FROM group_dept_access gda
INNER JOIN sys_department sd ON gda.dept_id = sd.dept_id
GROUP BY gda.group_id
) AS A ON sg.group_id = A.group_id
Looking for some help with optimising the query below. Seems to be two bottlenecks at the moment which cause it to take around 90s to complete the query. There's only 5000 products so it's not exactly a massive database/table. The bottlenecks are SQL_CALC_FOUND_ROWS and the ORDER BY statement - If I remove both of these it takes around a second to run the query.
I've tried removing SQL_CALC_FOUND_ROWS and running a count() statement, but that takes a long time as well..
Is the best thing going to be to use INNER JOIN's (which I'm not too familiar with) as per the following Stackoverflow post? Slow query when using ORDER BY
SELECT SQL_CALC_FOUND_ROWS *
FROM tbl_products
LEFT JOIN tbl_link_products_categories ON lpc_p_id = p_id
LEFT JOIN tbl_link_products_brands ON lpb_p_id = p_id
LEFT JOIN tbl_link_products_authors ON lpa_p_id = p_id
LEFT JOIN tbl_link_products_narrators ON lpn_p_id = p_id
LEFT JOIN tbl_linkfiles ON lf_id = p_id
AND (
lf_table = 'tbl_products'
OR lf_table IS NULL
)
LEFT JOIN tbl_files ON lf_file_id = file_id
AND (
file_nameid = 'p_main_image_'
OR file_nameid IS NULL
)
WHERE p_live = 'y'
ORDER BY p_title_clean ASC, p_title ASC
LIMIT 0 , 10
You could try reducing the size of the joins by using a derived table to retrieve the filtered and ordered products before joining. This assumes that p_live, p_title_clean and p_title are fields in your tbl_products table -
SELECT *
FROM (SELECT *
FROM tbl_products
WHERE p_live = 'y'
ORDER BY p_title_clean ASC, p_title ASC
LIMIT 0 , 10
) AS tbl_products
LEFT JOIN tbl_link_products_categories
ON lpc_p_id = p_id
LEFT JOIN tbl_link_products_brands
ON lpb_p_id = p_id
LEFT JOIN tbl_link_products_authors
ON lpa_p_id = p_id
LEFT JOIN tbl_link_products_narrators
ON lpn_p_id = p_id
LEFT JOIN tbl_linkfiles
ON lf_id = p_id
AND (
lf_table = 'tbl_products'
OR lf_table IS NULL
)
LEFT JOIN tbl_files
ON lf_file_id = file_id
AND (
file_nameid = 'p_main_image_'
OR file_nameid IS NULL
)
This is a "stab in the dark" as there is not enough detail in your question.
At the moment I can get the results I need with two seperate SELECT statements
SELECT
COUNT(rl.refBiblioID)
FROM biblioList bl
LEFT JOIN refList rl ON bl.biblioID = rl.biblioID
GROUP BY bl.biblioID
SELECT
GROUP_CONCAT(
CONCAT_WS( ':', al.lastName, al.firstName )
ORDER BY al.authorID )
FROM biblioList bl
LEFT JOIN biblio_author ba ON ba.biblioID = bl.biblioID
JOIN authorList al ON al.authorID = ba.authorID
GROUP BY bl.biblioID
Combining them like this however
SELECT
GROUP_CONCAT(
CONCAT_WS( ':', al.lastName, al.firstName )
ORDER BY al.authorID ),
COUNT(rl.refBiblioID)
FROM biblioList bl
LEFT JOIN biblio_author ba ON ba.biblioID = bl.biblioID
JOIN authorList al ON al.authorID = ba.authorID
LEFT JOIN refList rl ON bl.biblioID = rl.biblioID
GROUP BY bl.biblioID
causes the author result column to have duplicate names. How can I get the desired results from one SELECT statement without using DISTINCT? With subqueries?
If subselects are acceptable, I believe you could make this happen by doing something like this:
SELECT
y.authors,
COUNT(rl.refBiblioID)
FROM
(SELECT
bl.biblioId,
GROUP_CONCAT(
CONCAT_WS(':', al.lastName, al.firstName)
ORDER BY al.authorID) AS authors
FROM biblioList bl
LEFT JOIN biblio_author ba ON ba.biblioID = bl.biblioID
JOIN authorList al ON al.authorID = ba.authorID
GROUP BY bl.biblioID) y
LEFT JOIN refList rl ON (y.biblioID = rl.biblioID)
GROUP BY y.biblioID
Another solution would be to add DISTINCT to your GROUP_CONCAT, but that was not what you wanted?
GROUP_CONCAT(
DISTINCT(CONCAT_WS(':', al.lastName, al.firstName) ORDER BY al.authorID)),