Avoid filesort when having ORDER BY column in result - mysql

For a medical calendar, I've got the following query:
SELECT
`events`.`StartDate`,
`events`.`ID`,
`events`.`EndDate`,
`events`.`Title`,
`insurances`.`Title`,
`personsPatients`.`PrimaryPhone`,
`personsDocs`.`Name`
FROM `events`
LEFT JOIN `events++persons` ON `events`.`ID` = `events++persons`.`FirstEntityID` AND `events++persons`.`Type` = 'Patient'
LEFT JOIN `persons` AS `personsPatients` ON `events++persons`.`SecondEntityID` = `personsPatients`.`ID`
LEFT JOIN `insurances` ON `persons`.`Provider` = `insurances`.`ID`
LEFT JOIN `events++persons` AS `events++persons1` ON `events`.`ID` = `events++persons1`.`FirstEntityID` AND `events++persons1`.`Type` = 'Doctor'
LEFT JOIN `persons` AS `personsDoctors` ON `events++persons`.`SecondEntityID` = `personsDoctors`.`ID`
LEFT JOIN `companies++events` ON `events`.`ID` = `companies++events`.`SecondEntityID`
WHERE
((`events`.`Type` = 'Annotation' and `companies++events`.`FirstEntityID` IS NULL) or
(`events`.`Type` = 'Annotation' and `companies++events`.`FirstEntityID` = 1) or
(`events`.`Type` = 'Consultation' and `companies++events`.`FirstEntityID` = 1)) and
`events`.`StartDate` >= '2015-03-02 00:00:00' AND
`events`.`StartDate` <= '2015-03-07 23:59:59'
ORDER BY `events`.`StartDate` ASC
Events are linked via events++persons to two persons: A doctor and a patient.
This query is enormously slow.
When I remove the ORDER BY (which is essential), the filesort and the temp table vanish. Any help is greatly appreciated!

The problem lies with companies++events - all the one-to-one LEFT JOINs in the world don't help when the criterion comes only at the end. I managed to move that info into the main entity (kind of like a pointer) and create a covering index, now the query is lightning-fast.

Related

How to access outer table data in join where

How can I access data from an outer table in a SELECT, and use it in an WHERE inside a JOIN estructure?
Below is the current query:
SELECT
cvl.id caracteristica_valor_id,
cvl.nome caracteristica_valor_nome,
cvl.valor caracteristica_valor_valor,
ctp.id caracteristica_tipo_id,
ctp.nome caracteristica_tipo_nome,
ctp.codigo caracteristica_tipo_codigo,
ctp.tipo caracteristica_tipo_tipo,
COUNT(DISTINCT var.id_perfil_produto) quantidade_itens
FROM
caracteristica_variacao cvr
INNER JOIN caracteristica_valor cvl ON cvl.id = cvr.id_caracteristica_valor
INNER JOIN caracteristica_tipo ctp ON ctp.id = cvl.id_caracteristica_tipo
INNER JOIN variacao var ON var.id = cvr.id_variacao
INNER JOIN(
SELECT DISTINCT
ppr.id perfil_produto_id
FROM
perfil_produto ppr
INNER JOIN produto pro ON pro.id = ppr.id_produto
INNER JOIN(
SELECT ppr2.id AS id_perfil_sub,a
COUNT(var.id) AS qtd_variacoes,
SUM(var.quantidade_estoque) AS quantidade_estoque,
COALESCE(SUM(var.quantidade_estoque_reservada),0) AS quantidade_estoque_reservada,
MIN(var.disponibilidade) AS disponibilidade,
MIN(var.frete_gratis) AS frete_gratis,
MIN(var.preco_venda) AS preco_venda,
MAX(var.preco_listagem) AS preco_listagem
FROM
variacao var
LEFT JOIN perfil_produto ppr2 ON ppr2.id = var.id_perfil_produto
LEFT JOIN caracteristica_variacao cvr_1 ON cvr_1.id_variacao = var.id
LEFT JOIN caracteristica_valor cvl_1 ON cvl_1.id = cvr_1.id_caracteristica_valor
LEFT JOIN caracteristica_tipo ctp_1 ON ctp_1.id = cvl_1.id_caracteristica_tipo
WHERE
var.disponibilidade = 1
AND(
ctp_1.codigo = 'tamanho' AND cvl_1.valor IN('p')
)
GROUP BY
ppr2.id
) AS grp_var ON grp_var.id_perfil_sub = ppr.id
INNER JOIN produto_categoria prc ON pro.id = prc.produto_id
INNER JOIN categoria cat ON prc.categoria_id = cat.id
WHERE
pro.disponibilidade = 1 AND prc.categoria_id IN (164, 165, 166)
) AS produto ON produto.perfil_produto_id = var.id_perfil_produto
GROUP BY
cvl.id
ORDER BY
ctp.tipo ASC,
ctp.id
I need the field ctp.codigo from the outer table inside thist part:
WHERE
var.disponibilidade = 1
AND(
ctp_1.codigo = 'tamanho' AND cvl_1.valor IN('p')
)
for this section to be as follows:
WHERE
var.disponibilidade = 1
AND(
(ctp.codigo != 'tamanho' AND ctp_1.codigo = 'tamanho' AND cvl_1.valor IN('p'))
OR
(ctp.codigo = 'tamanho')
)
It's not possible to reference columns from the outer query from inside an inline view query.
In the MySQL venacular, the inline view query is called a "derived table". And that name makes sense, because of the way MySQL processes it. The execution plan first materializes the inline view query into a temporary(-ish) table. Once that is done, then the outer query can run, referencing the contents of the derived table.
MySQL doesn't have available the columns from the outer query at the time the inline view query runs.
It is possible to reference columns from the outer query inside a subquery that appears for example in the SELECT list, or in the WHERE clause. We call a subquery that references columns from outer query a "correlated subquery".

Mysql tekes too much time to excute sql query, based on multiple join

My Sql query takes more time to execute from mysql database server . There are number of tables are joined with sb_tblproperty table. sb_tblproperty is main table that contain more than 1,00,000 rows . most of table contain 50,000 rows.
How to optimize my sql query to fast execution. I have also used indexing.
indexing Explain - query - structure
SELECT `t1`.`propertyId`, `t1`.`projectId`,
`t1`.`furnised`, `t1`.`ownerID`, `t1`.`subType`,
`t1`.`fors`, `t1`.`size`, `t1`.`unit`,
`t1`.`bedrooms`, `t1`.`address`, `t1`.`dateConfirm`,
`t1`.`dateAdded`, `t1`.`floor`, `t1`.`priceAmount`,
`t1`.`priceRate`, `t1`.`allInclusive`, `t1`.`booking`,
`t1`.`bookingRate`, `t1`.`paidPercetage`,
`t1`.`paidAmount`, `t1`.`is_sold`, `t1`.`remarks`,
`t1`.`status`, `t1`.`confirmedStatus`, `t1`.`source`,
`t1`.`companyName` as company, `t1`.`monthly_rent`,
`t1`.`per_sqft`, `t1`.`lease_duration`,
`t1`.`lease_commencement`, `t1`.`lock_in_period`,
`t1`.`security_deposit`, `t1`.`security_amount`,
`t1`.`total_area_leased`, `t1`.`lease_escalation_amount`,
`t1`.`lease_escalation_years`, `t2`.`propertyTypeName` as
propertyTypeName, `t3`.`propertySubTypeName` subType,
`t3`.`propertySubTypeId` subTypeId, `Owner`.`ContactName`
ownerName, `Owner`.`companyName`, `Owner`.`mobile1`,
`Owner`.`otherPhoneNo`, `Owner`.`mobile2`,
`Owner`.`email`, `Owner`.`address` as caddress,
`Owner`.`contactType`, `P`.`projectName` as project,
`P`.`developerName` as developer, `c`.`name` as city,
if(t1.projectId="", group_concat( distinct( L.locality)),
group_concat( distinct(L2.locality))) as locality, `U`.`firstname`
addedBy, `U1`.`firstname` confirmedBy
FROM `sb_tblproperty` as t1
JOIN `sb_contact` Owner ON `Owner`.`id` = `t1`.`ownerID`
JOIN `tbl_city` C ON `c`.`id` = `t1`.`city`
JOIN `sb_propertytype` t2 ON `t1`.`propertyType`= `t2`.`propertyTypeId`
JOIN `sb_propertysubtype` t3 ON `t1`.`subType` =`t3`.`propertySubTypeId`
LEFT JOIN `sb_tbluser` U ON `t1`.`addedBy` = `U`.`userId`
LEFT JOIN`sb_tbluser` U1 ON `t1`.`confirmedBy` = `U1`.`userId`
LEFT JOIN `sb_tblproject` P ON `P`.`id` = `t1`.`projectId` LEFT
JOIN `sb_tblpropertylocality` PL ON `t1`.`propertyId` = `PL`.`propertyId`
LEFT JOIN `sa_localitiez` L ON `L`.`id` = `PL`.`localityId`
LEFT JOIN `sb_tblprojectlocality` PROL ON `PROL`.`projectId` = `P`.`id`
LEFT JOIN `sa_localitiez` L2 ON `L2`.`id` = `PROL`.`localityId`
LEFT JOIN `sb_tblfloor` F
ON `F`.`floorName` =`t1`.`floor`
WHERE `t1`.`is_sold` != '1' GROUP BY `t1`.`propertyId`
ORDER BY `t1`.`dateConfirm`
DESC LIMIT 1000
Please provide the EXPLAIN.
Meanwhile, try this:
SELECT ...
FROM (
SELECT propertyId
FROM sb_tblproperty
WHERE `is_sold` = 0
ORDER BY `dateConfirm` DESC
LIMIT 1000
) AS x
JOIN `sb_tblproperty` as t1 ON t1.propertyId = x.propertyId
JOIN `sb_contact` Owner ON `Owner`.`id` = `t1`.`ownerID`
JOIN `tbl_city` C ON `c`.`id` = `t1`.`city`
...
LEFT JOIN `sb_tblfloor` F ON `F`.`floorName` =`t1`.`floor`
ORDER BY `t1`.`dateConfirm` DESC -- yes, again
Together with
INDEX(is_sold, dateConfirm)
How can t1.projectId="" ? Isn't projectId the PRIMARY KEY? (This is one of many reasons for needing the SHOW CREATE TABLE.)
If my suggestion leads to "duplicate" rows (that is, multiple rows with the same propertyId), don't simply add back the GROUP BY propertyId. Instead figure out why, and avoid the need for the GROUP BY. (That is probably the performance issue.)
A likely case is the GROUP_CONCAT. A common workaround is to change from
GROUP_CONCAT( distinct( L.locality)) AS Localities,
...
LEFT JOIN `sa_localitiez` L ON `L`.`id` = `PL`.`localityId`
to
( SELECT GROUP_CONCAT(distinct locality)
FROM sa_localitiez
WHERE id = PL.localityId ) AS Localities
...
# and remove the JOIN

Rails - How to force associations to use alias table name

p = Patient.find(30)
p.patient_problems
The above code generates the following query
SELECT `patient_problem`.* FROM `patient_problem` WHERE `patient_problem`.`patient_id` = 30 AND (`patient_problem`.`record_status_id` = 1)
But is there any way to assign/use alias table_name like
p.patient_problems(:alias=>'p1') # just for Ex.. This code will not work
p.patient_problems(:alias=>'p2') # just for Ex.. This code will not work
So it will generate the following queries
SELECT `p1`.* FROM `patient_problem` AS `p1` WHERE `p1`.`patient_id` = 30 AND (`p1`.`record_status_id` = 1)
SELECT `p2`.* FROM `patient_problem` AS `p2` WHERE `p2`.`patient_id` = 30 AND (`p2`.`record_status_id` = 1)
Additional Info
My problem is when I try to use joins
p.patient_problems(:all,:joins=>joins)
I get this error
ActionView::Template::Error (Mysql2::Error: Not unique table/alias: 'patient_problem': SELECT `patient_problem`.* FROM `patient_problem` LEFT OUTER JOIN party on party.id = patient_problem.patient_id
LEFT OUTER JOIN party_identifier on party.id = party_identifier.party_id
LEFT OUTER JOIN blood_type on blood_type.id = party.blood_type_id
LEFT OUTER JOIN education_level on education_level.id = party.education_level_id
LEFT OUTER JOIN religion on religion.id = party.religion_id
LEFT OUTER JOIN living_arrangement on living_arrangement.id = party.living_arrangement_id
LEFT OUTER JOIN patient_problem patient_problem on patient_problem.patient_id = party.id and patient_problem.record_status_id = 1
left join (select user_type,username,user_id,auditable_id from (select MAX(id) id from audits where audits.auditable_type = 'PatientProblem' and user_type is not null group by auditable_id ) t inner join audits v on v.id=t.id ) entered_by1 on entered_by1.auditable_id = patient_problem.id
left outer join user user1 on entered_by1.user_id = user1.id
left outer join party as party_user1 on party_user1.id = user1.person_id
LEFT OUTER JOIN patient_patient_search patient_patient_search1 on patient_patient_search1.patient_id = party.id
left join search search1 on patient_patient_search1.patient_search_id = search1.id
and patient_patient_search1.patient_search_id = '75' WHERE `patient_problem`.`patient_id` = 45 AND (`patient_problem`.`record_status_id` = 1) AND ( (patient_problem.occurrence_date > '2013-01-01 00:00:00' and patient_problem.occurrence_date < '2013-06-30 23:59:59' and patient_problem.patient_problem_status_id in (5) and patient_problem.code is not null and patient_problem.code in ('10725009') ) and ( patient_patient_search1.patient_search_id in (75.0) ) ))
Ofcourse I could do some string manipulation on the generated joins query and set alias to patient_problem. But I thought setting alias for associations would be more cleaner since the joins query generated are unpredictable(in my scenario)
I am not sure what the variable joins is or how it was constructed. To alias tables in a join build your query like
Rails 3
PatientProblem.joins("as p1 OUTER JOIN patient_problem as p2 on ...")
or
PatientProblem.find(:all, :joins => "as p1 OUTER JOIN patient_problem as p2 ON ...")
you can make singleton methods for that and write the query one time and use may time like
def self.p1
#your active record query here.
end
and call like
PatientProblem.p1
Update
You can simply change the table name in your code:
Patient.table_name="p2"
I'm not sure if this would break anything else though ... so good luck!
Orignal Answer
One solution may be to define a separate model for each type of patient_problem and then do something like this:
class PatientProblem2 < ActiveRecord::Base
self.set_table_name "p2"
...
end
Another solution may be to use the ActiveRecord query interface which will allows for significant query flexibility:
http://guides.rubyonrails.org/active_record_querying.html
Perhaps you can be more specific on the nature problem you are trying to solve.

MySQL - Multirow Sum without Subquery

I currently have this working using a Sub-query, but as the DB grows this will become HUGELY inefficient. I'm wondering if there is a more efficient way to do what I need to do without sub-queries?
I need to have my final output look like so:
Question, Answer, Responses, Charts included in Response Count
Did this work?, N/A, 26, 30
Did this work?, Yes, 4, 30
This is my current query:
SELECT
bq_text,
ba_a,
bq_id,
COUNT(ba_a) AS ba_aC,
(SELECT COUNT(*) FROM board_done_sheet WHERE sd_b_id = bs.bs_id AND sd_sub = 1) AS sd_chartnumC
FROM board_done_sheet AS sh
LEFT JOIN board_done bd
ON (bd.bd_id = sh.sd_bd_id)
LEFT JOIN boardsubs bs
ON (bd.bd_b_id = bs.bs_id)
LEFT JOIN b_q_answers ba
ON (sh.sd_s_id = ba.ba_s_id)
LEFT JOIN bsquestions bq
ON (bq.bq_id = ba.ba_q_id)
LEFT JOIN multiples m
ON (ba.ba_m_id = m.m_id)
LEFT JOIN users u
ON (u.us_id = bd.bd_d_id)
LEFT JOIN profiles p
ON (p.p_u_id = bd.bd_d_id)
LEFT JOIN users rev
ON (rev.us_id = bd.bd_rev)
WHERE sd_sub = '1' AND bq_text <> 'Date' AND bq_id = 380
GROUP BY bs_id, bq_text, ba_a
That works perfectly, the problem is it has to use sub-queries which as time goes by will get less efficient.
I'm just wondering if there is a better more efficient way to do that summed field without it.
Presumably the subquery you're concerned about is the one in your toplevel SELECT.
That is easy to refactor so it won't get repeated.
Just JOIN it to the rest of the table. You'll want this sort of thing:
SELECT
bq_text, ...
COUNT(ba_a) AS ba_aC,
countup.countup AS sd_chartnumC
FROM board_done_sheet AS sh
LEFT JOIN board_done bd
ON (bd.bd_id = sh.sd_bd_id)
...
LEFT JOIN users rev
ON (rev.us_id = bd.bd_rev)
JOIN (
SELECT COUNT(*) AS countup , sd_b_id
FROM board_done_sheet
WHERE sd_sub = 1
GROUP BY sd_b_id
) AS countup ON countup.sd_b_id = bs.bs_id
WHERE sd_sub = '1'
AND bq_text <> 'Date'
AND bq_id = 380
GROUP BY bs_id, bq_text, ba_a
The countup subquery generates a summary table of counts and ids, and then joins it to the other tables.
A JOIN cascade of this complexity may become inefficient for other reasons as your table grows if you don't structure your indexes correctly.

SQL Query producing wrong count result

I have the following SQL query
SELECT
DISTINCT
count("SiteTree_Live"."ID")
FROM
"SiteTree_Live"
LEFT JOIN "Page_Live" ON "Page_Live"."ID" = "SiteTree_Live"."ID"
LEFT JOIN "TourPage_Live" ON "TourPage_Live"."ID" = "SiteTree_Live"."ID"
LEFT JOIN "DepartureDate" ON "DepartureDate"."TourID" = "SiteTree_Live"."ID"
WHERE
("SiteTree_Live"."Locale" = 'en_AU')
AND ("SiteTree_Live"."ClassName" IN ('TourPage'))
AND ("DepartureDate"."DepartureDate" LIKE '2012-11%')
but it producing a wrong count as the query result. The total intented result this query is suppose to return should not be more than 245 but currently, its returning more than about "4569" results.
Thats is because of the JOIN on the "DepartureDate" table as the query returns the expected result when i remove the join from the "DepartureDate" table.
What modification do i need to make to my query to count the Macthes between "SiteTree_Live"."ID" and "DepartureDate"."TourID" whiles counting only the "SiteTree_Live"."ID" count excluding the Departure dates?
Any suggestions welcomed :)
THE ANSWER
SELECT
COUNT(DISTINCT SiteTree_Live.ID)
FROM
"SiteTree_Live" LEFT JOIN "Page_Live" ON "Page_Live"."ID" = "SiteTree_Live"."ID"
LEFT JOIN "TourPage_Live" ON "TourPage_Live"."ID" = "SiteTree_Live"."ID"
LEFT JOIN "DepartureDate" ON "DepartureDate"."TourID" = "SiteTree_Live"."ID"
WHERE
("SiteTree_Live"."Locale" = 'en_AU')
AND ("SiteTree_Live"."ClassName" IN ('TourPage'))
AND ("DepartureDate"."DepartureDate" LIKE '2013-03%')
Seems to give me the right result. Thanks for the tip #Michael Berkowski
Minor correction: if DepartureDate is a date-type, then the LIKE '2013-03% will force it to be coerced into a character type (this is a mysql feature) As a result, any indexes on DepartureDate will not be used, IIRC. Better use a plain range-query:
SELECT
COUNT(DISTINCT stl.ID)
FROM
SiteTree_Live stl
LEFT JOIN
DepartureDate dd ON dd.TourID = stl.ID
WHERE
stl.Locale = 'en_AU'
AND stl.ClassName = 'TourPage'
AND dd.DepartureDate >= '2013-03-01'
AND dd.DepartureDate < '2013-04-01'
;
Do this (You have a bunch of unneeded joins)
SELECT
COUNT(DISTINCT SiteTree_Live.ID)
FROM
`SiteTree_Live`
LEFT JOIN
`DepartureDate` ON `DepartureDate`.`TourID` = `SiteTree_Live`.`ID`
WHERE
`SiteTree_Live`.`Locale` = 'en_AU'
AND `SiteTree_Live`.`ClassName` = 'TourPage'
AND `DepartureDate`.`DepartureDate` LIKE '2013-03%'
You could also do a GROUP BY:
SELECT
COUNT(SiteTree_Live.ID)
FROM
`SiteTree_Live`
LEFT JOIN
`DepartureDate` ON `DepartureDate`.`TourID` = `SiteTree_Live`.`ID`
WHERE
`SiteTree_Live`.`Locale` = 'en_AU'
AND `SiteTree_Live`.`ClassName` = 'TourPage'
AND `DepartureDate`.`DepartureDate` LIKE '2013-03%'
GROUP BY
SiteTree_Live.ID