Some may or may not consider this a complex statement, but for me (since I've only been doing statement for about a month) this one is. The below statement returns me the exact results I am looking for, but my problem is that it take over 95 seconds to run on a iMac. I need this statement to run on an iPhone. Can anyone thing of a better (quicker) way to do this?
select categories.category
from categories join categories_listings
where categories_listings.category_id = categories.id
and categories.association_id = 1
and (select count(*)
from (select (
select categories.category
from categories left join categories_listings
where categories_listings.category_id = categories.id
and categories.association_id = 1
and listings.id = categories_listings.listing_id) as region
from listings left join chamber_specifics
on chamber_specifics.listing_id=listings.id
where region = categories.category
and listings.association_id=1
and listings.status = 1
and downtown='Y')) >0
group by categories.category;
Let me know if more info is needed.
Thanks!
I came up with a statement that gets me the same results as in my question, but much fast at about 0.062 seconds to complete. Below is my Statement: (Thanks Rudu for the direction!)
select (
select categories.category
from categories left join categories_listings
where categories_listings.category_id = categories.id
and categories.association_id = 1
and listings.id = categories_listings.listing_id) as region
from listings left join chamber_specifics
on chamber_specifics.listing_id=listings.id
where listings.association_id=1
and listings.status = 1
and downtown='Y'
group by region
Related
I've been trying to improve a SQL query which uses multiple sub queries over the same table but with different conditions and only retrieves the first result from each sub queries.
I will try to simplify the use-case :
I have a table Products like this:
Product_id
reference
field3
field 4
1
ref1
val1
val3
2
ref2
val2
val4
And another table History:
History_id
reference
utilcode
physicalcode
issue
media
datetime
1
ref1
'test'
'TST'
'0'
'&audio'
'a_date'
2
ref2
'phone'
'CALLER'
'1'
'&video'
'a_date'
3
ref2
'test'
'CALLER'
'2'
'&test'
'a_date'
History is a log table and therefore contains a lot of values.
Now I have a query like this
SELECT
p.reference,
p.field3, p.field4,
(SELECT TOP 1 a_date
FROM history h
WHERE h.reference = p.reference
AND physicalcode = 'TST'
AND issue = 0
ORDER BY a_date DESC) AS latest_date_issue_0,
(SELECT TOP 1 a_date
FROM history h
WHERE h.reference = p.reference
AND physicalcode = 'TST'
AND issue = 1
ORDER BY a_date DESC) AS latest_date_issue_1
(SELECT TOP 1 a_date
FROM history h
WHERE h.reference = p.reference
AND utilcode = 'phone'
ORDER BY a_date DESC) AS latest_date_phone,
(SELECT TOP 1 media
FROM history h
WHERE h.reference = p.reference
AND utilcode = 'phone'
ORDER BY a_date DESC) AS latest_media,
-- and so on with many possible combinations
-- Note that there are more than this few fields on the tables I work on.
WHERE
p.field3 = 'valX',
p.field4 = 'valY'
FROM
products p
How could I merge every sub selects ? Or even a few that are alike to improve the performance ?
History being a very big table, selecting over it multiple times drastically slows down the query.
The main problem being that I only need the first value every time.
Thank you for your time and I hope to find a better way to deal with this issue!
I tried to use ROW_NUMBER() but I could not find a suitable way to use it.
I also tried to create a tmp table using WITH to group every possibility from history but it was worse.
EDIT : Execution plan https://www.brentozar.com/pastetheplan/?id=Sy1AKIsUs
You can convert your correlated subqueries (you call them "subselects") to independent subqueries, then JOIN them. That way each subquery will only need to run once. I'll show you how to do this for your first subquery.
Here's a subquery replacing your first subquery.
SELECT reference, MAX(a_date) a_date
FROM history
WHERE physicalcode = 'TST'
AND issue = 0
GROUP BY reference
This gives a virtual table containing the latest date for each reference number from the history table matching the criteria in your question. A multicolumn index on history (physicalcode, issue, reference, a_date) makes this fast.
Then you can join it to the main table something like this:
SELECT
p.reference,
p.field3, p.field4,
a.a_date a_date_issue_0
FROM products p
LEFT JOIN ( /*the subquery */
SELECT reference, MAX(a_date) a_date
FROM history
WHERE physicalcode = 'TST'
AND issue = 0
GROUP BY reference
) a ON p.reference=a.reference
These subqueries can also be defined as VIEWs or Common Table Expressions (CTEs). If you have many of them you'll probably find it easier to read and reason about your query by doing them that way.
Your last subquery is a little trickier to handle this way. I suggest you work with this answer and then maybe ask another question about that.
Thanks to #O.Jones I've been able to find a way to improve this query.
What I did to merge a few requests was to use a CTE like so :
From
SELECT
(SELECT TOP 1 a_date
FROM history h
WHERE h.reference = p.reference
AND physicalcode = 'TST'
AND issue = 0
ORDER BY a_date DESC) AS latest_date_issue_0,
(SELECT TOP 1 a_date
FROM history h
WHERE h.reference = p.reference
AND physicalcode = 'TST'
AND issue = 1
ORDER BY a_date DESC) AS latest_date_issue_1
(SELECT top 1 a_date
FROM history h
WHERE h.reference = p.reference
AND h.physicalcode = 'TSTKO'
ORDER BY h.d_systeme DESC ) AS d_tst_ko,
(SELECT top 1 a_date
FROM history h
WHERE h.reference = p.reference
AND h.physicalcode = 'CALLERID'
ORDER BY h.d_systeme DESC ) AS d_wrong_number
FROM products p
To
WITH physicalcode_cte (reference, physicalcode, issue, a_date) as
(
SELECT reference, physicalcode, issue, max(a_date)
from historique
where codephysique in ('TST','TSTKO','CALLERID')
and a_date > dateadd(month, -4, getdate()) -- filter on date range to reduce number of rows
group by reference, physicalcode, issue
)
SELECT
date_issue_0.a_date,
date_issue_1.a_date,
tst_ko.a_date,
wrong_number.a_date
FROM products p
LEFT JOIN physicalcode_cte date_issue_0 on p.reference = date_issue_0.reference
AND date_issue_0.codephysique = 'TST'
AND date_issue_0.anomalie = 0
LEFT JOIN physicalcode_cte date_issue_1 on p.reference = date_issue_1.reference
AND date_issue_1.codephysique = 'TST'
AND date_issue_1.anomalie = 1
LEFT JOIN physicalcode_cte tst_ko on p.reference = tst_ko.reference
AND tst_ko.codephysique = 'TST'
LEFT JOIN physicalcode_cte wrong_number on p.reference = wrong_number.reference AND
AND wrong_number.codephysique = 'TST'
I've applied this idea for different scenarii and made 2 CTE.
I couldn't merge everything, sometime merging caused cost increase. But after several tests I've been able to go from 7100 total cost to 2100.
It is still a lot but 3 times less anyway. Takes 5 seconds instead of a timeout.
It's a query used for monthly reports so I don't need it to be super fast, I will keep it that way.
Thanks you!
I need to select grade_name from tblgrade, subject_name from tblsubject, count (subscribe_id) from tblsubcription, count (sub_status) from tblsubcription where sub_status=1 and count (sub_status) from tblsubcription where sub_status is null.
This is what i have tried:
SELECT t2.grade_name,
t.subject_name,
(SELECT COUNT(*)
FROM tblsubcription
WHERE sub_status IS NULL
AND teacher_id = 2) AS pending,
(SELECT COUNT(*)
FROM tblsubcription
WHERE sub_status = '1'
AND teacher_id = 2) AS appoved,
COUNT(t1.subscribe_id) AS totalsub
FROM tblsubject t
INNER JOIN tblsubject_grade tg ON (t.subject_id = tg.subject_id)
INNER JOIN tblsubcription t1 ON (tg.subject_garde_id = t1.subject_garde_id)
INNER JOIN tblgrade t2 ON (tg.grade_id = t2.grade_id)
AND tg.grade_id = t2.grade_id
AND tg.subject_id = t.subject_id
AND t2.admin_id = t.admin_id
WHERE t1.teacher_id = 2
GROUP BY t.subject_name,
t2.grade_name;
See result obtained when the above query is executed and the expected result i need is in red
Looking at this subquery:
(SELECT COUNT(*)
FROM tblsubcription
WHERE sub_status IS NULL
AND teacher_id = 2) AS pending,
There is nothing here to relate (correlate) it to the specific row. You need an additional condition in the WHERE clause that tells you which Grade/Subject pair to look at. The other (approved) subquery is the same way.
Alternatively, you may be able to solve this with another join to tblsubscription and conditional aggregation.
I'd post code to fix this, but I find the images too blurry to read well, so I can't easily infer which fields to use. Next time post formatted text, and you'll get a better answer in less time.
I have an SQL query, it is running on MSSQL 2008 R2
View vMobileLastMobileHistory has about 1000 rows and
select * from vMobileLastMobileHistory is taking 0.2 sec
but this query is taking 5 seconds, how can I optimize this code?
(I think the problem is INTERSECT but I dont know how change this)
SELECT DISTINCT *
FROM
(
SELECT vMobileLastMobileHistory.*
FROM vMobileLastMobileHistory
LEFT OUTER JOIN MobileType_DomainAction ON
MobileType_DomainAction.tiMobileType = vMobileLastMobileHistory.tiMobileType
LEFT OUTER JOIN MobileType_User ON
MobileType_User.MobileID = MobileType_DomainAction.ID
WHERE MobileType_User.UserID = #UserID OR #UserID = - 1
INTERSECT
SELECT vMobileLastMobileHistory.*
FROM vMobileLastMobileHistory
LEFT OUTER JOIN dbo.Region_User ON
dbo.vMobileLastMobileHistory.strRegion = dbo.Region_User.strRegion
WHERE Region_User.iSystemUser = #UserID OR #UserID = - 1
INTERSECT
SELECT vMobileLastMobileHistory.*
FROM vMobileLastMobileHistory
LEFT OUTER JOIN Contractor_User ON
vMobileLastMobileHistory.strContractor = Contractor_User.strContractor
WHERE Contractor_User.iSystemUser = #UserID OR #UserID = - 1
)
The problem is that if you have any indexes on your iSytemUser columns, the optimise is unable to use them because it has to account for a specific userID being passed, or returning all results, it would be better to logically separate your two cases. In addition, since you don't care about any columns in the auxiliary tables, you could use EXISTS in your case of specific users to take advantage of a semi join:
IF (#UserID = -1)
BEGIN
SELECT DISTINCT *
FROM vMobileLastMobileHistory;
END
ELSE
BEGIN
SELECT DISTINCT *
FROM vMobileLastMobileHistory AS mh
WHERE EXISTS
( SELECT 1
FROM Contractor_User AS cu
WHERE cu.strContractor = mh.strContractor
AND cu.iSystemUser = #UserID
)
AND EXISTS
( SELECT 1
FROM Region_User AS ru
WHERE ru.strRegion = mh.strRegion
AND ru.iSystemUser = #UserID
)
AND EXISTS
( SELECT 1
FROM MobileType_DomainAction AS da
INNER JOIN MobileType_User AS mu
ON mu.MobileID = da.ID
WHERE da.tiMobileType = mh.tiMobileType
AND mu.iSystemUser = #UserID
);
END
Now you can have two execution plans for each case (returning all results, or for a specific user), in each case you only need to read from vMobileLastMobileHistory once, and you also limit the sorts required by removing the INTERSECT and replacing with 3 EXISTS clauses.
If they don't already exist then you may also which to consider some indexes on your tables. A good way of finding out what indexes would help is to run the query in SQL Server Management Studio with the option "Show Actual Execution Plan" enabled, this will then show you any missing indexes.
Most of time Intersect and Inner Join will be same. You are not share your data, so based on my knowledge and this link, I just replace intersect query into Inner join query as :
--I think you don't need distinct upper query. If you have issue inform me.
SELECT DISTINCT vml.*
FROM vMobileLastMobileHistory vml
LEFT OUTER JOIN MobileType_DomainAction mtda ON mtda.tiMobileType = vml.tiMobileType
LEFT OUTER JOIN MobileType_User ON MobileType_User.MobileID = mtda.ID
LEFT OUTER JOIN dbo.Region_User ON dbo.vml.strRegion = dbo.Region_User.strRegion
LEFT OUTER JOIN Contractor_User ON vml.strContractor = Contractor_User.strContractor
WHERE
(MobileType_User.UserID = #UserID
and Region_User.iSystemUser = #UserID or Contractor_User.iSystemUser = #UserID
) OR #UserID = - 1
I have a complex query to retrieve some results:
EDITED QUERY (added the UNION ALL):
SELECT t.*
FROM (
SELECT
dbo.Intervencao.INT_Processo, analista,
ETS.ETS_Sigla, ATC.ATC_Sigla, PAT.PAT_Sigla, dbo.Assunto.SNT_Peso,
CASE
WHEN ETS.ETS_Sigla = 'PE' AND (PAT.PAT_Sigla = 'LIB' OR PAT.PAT_Sigla = 'LBR') THEN (0.3*SNT_Peso)
WHEN ETS.ETS_Sigla = 'CD' THEN (0.3*SNT_Peso)*0.3
ELSE SNT_Peso
END AS PESOAREA,
CASE
WHEN a.max_TEA_FimTarefa IS NULL THEN a.max_TEA_InicioTarefa
ELSE a.max_TEA_FimTarefa
END AS DATA_INICIO_TERMINO,
ROW_NUMBER() OVER (PARTITION BY ATC.ATC_Sigla, a.SRV_Id ORDER BY TEA_FimTarefa DESC) AS seqnum
FROM dbo.Tarefa AS t
INNER JOIN (
SELECT
MAX(dbo.TarefaEtapaAreaTecnica.TEA_InicioTarefa) AS max_TEA_InicioTarefa,
MAX (dbo.TarefaEtapaAreaTecnica.TEA_FimTarefa) AS max_TEA_FimTarefa,
dbo.Pessoa.PFJ_Descri AS analista, dbo.AreaTecnica.ATC_Id, dbo.Tarefa.SRV_Id
FROM dbo.TarefaEtapaAreaTecnica
LEFT JOIN dbo.Tarefa ON dbo.TarefaEtapaAreaTecnica.TRF_Id = dbo.Tarefa.TRF_Id
LEFT JOIN dbo.AreaTecnica ON dbo.TarefaEtapaAreaTecnica.ATC_Id = dbo.AreaTecnica.ATC_Id
LEFT JOIN dbo.ServicoAreaTecnica ON dbo.TarefaEtapaAreaTecnica.ATC_Id = dbo.ServicoAreaTecnica.ATC_Id
AND dbo.Tarefa.SRV_Id = dbo.ServicoAreaTecnica.SRV_Id
INNER JOIN dbo.Pessoa ON dbo.Pessoa.PFJ_Id = dbo.ServicoAreaTecnica.PFJ_Id_Analista
GROUP BY dbo.AreaTecnica.ATC_Id, dbo.Tarefa.SRV_Id, dbo.Pessoa.PFJ_Descri
) AS a ON t.SRV_Id = a.SRV_Id
INNER JOIN dbo.TarefaEtapaAreaTecnica AS TarefaEtapaAreaTecnica_1 ON
t.TRF_Id = TarefaEtapaAreaTecnica_1.TRF_Id
AND a.ATC_Id = TarefaEtapaAreaTecnica_1.ATC_Id
AND a.max_TEA_InicioTarefa = TarefaEtapaAreaTecnica_1.TEA_InicioTarefa
LEFT JOIN AreaTecnica ATC ON TarefaEtapaAreaTecnica_1.ATC_Id = ATC.ATC_Id
LEFT JOIN Etapa ETS ON TarefaEtapaAreaTecnica_1.ETS_Id = ETS.ETS_Id
LEFT JOIN ParecerTipo PAT ON TarefaEtapaAreaTecnica_1.PAT_Id = PAT.PAT_Id
LEFT OUTER JOIN dbo.Servico ON a.SRV_Id = dbo.Servico.SRV_Id
INNER JOIN dbo.Intervencao ON dbo.Servico.INT_Id = dbo.Intervencao.INT_Id
LEFT JOIN dbo.Assunto ON dbo.Servico.SNT_Id = dbo.Assunto.SNT_Id
) t
The result is following:
It works good, the problem is that I was asked that if when a row is not present on this query, it must contain values from another table (ServicoAreaTecnica), so I got this query for the other table based on crucial information of the first query. So if I UNION ALL I get this:
Query1 +
UNION ALL
SELECT INN.INT_Processo,
PES.PFJ_Descri,
NULL, --ETS.ETS_Sigla,
ART.ATC_Sigla,
NULL ,--PAT.PAT_Sigla,
ASS.SNT_Peso,
NULL, --PESOAREA
NULL, --DATA_INICIO_TERMINO
NULL --seqnum
FROM dbo.ServicoAreaTecnica AS SAT
INNER JOIN dbo.AreaTecnica AS ART ON ART.ATC_Id = SAT.ATC_Id
INNER JOIN dbo.Servico AS SER ON SER.SRV_Id = SAT.SRV_Id
INNER JOIN dbo.Assunto AS ASS ON ASS.SNT_Id = SER.SNT_Id
INNER JOIN dbo.Intervencao AS INN ON INN.INT_Id = SER.INT_Id
INNER JOIN dbo.Pessoa AS PES ON PES.PFJ_Id = SAT.PFJ_Id_Analista
The result is following:
So what I want to do is to remove row number 1 because row number 2 exists on the first query, I think I got it explained better this time. The result should be only row number 1, row number 2 would appear only if query 1 doesn't retrieve a row for that particular INN.INT_Processo.
Thanks!
Ok, there are two ways to reduce your record set. Given that you've already written the code to produce the table with the extra rows, it might be easiest to just add code to reduce that:
Select * from
(Select *
, Row_Number() over
(partition by IntProcesso, Analista order by ISNULL(seqnum, 0) desc) as RN
from MyResults) a
where RN = 1
This will assign row_number 1 to any rows that came from your first query, or to any rows from the second query that do not have matches in the first query, then filter out extra rows.
You could also use outer joins with isnull or coalesce, as others have suggested. Something like this:
Select ISNULL(a.IntProcesso, b.IntProcesso) as IntProcesso
, ISNULL(a.Analista, b.Analista) as Analista
, ISNULL(a.ETSsigla, b.ETSsigla) as ETSsigla
[repeat for the rest of your columns]
from Table1 a
full outer join Table2 b
on a.IntProcesso = b.IntProcesso and a.Analista = b.Analista
Your code is hard to read, because of the lengthy names of everything (and to be honest, the fact that they're in a language I don't speak also makes it a lot harder).
But how about: replacing your INNER JOINs with LEFT JOINs, adding more LEFT JOINs to draw in the alternative tables, and introducing ISNULL clauses for each variable you want in the results?
If you do something like ... Query1 Right Join Query2 On ... that should get only the rows in Query2 that don't appear in Query 1.
SELECT videos.id, videos.game_id, videos.xbox360, videos.ps3, videos.pc,
videos.wii, videos.other, videos.thumbnail, videos.vid_info, videos.sdvid,
videos.hdvid, UNIX_TIMESTAMP( videos.date_added ) , game_data.name,
AVG( video_ratings.rating )
FROM videos, game_data, video_ratings
WHERE videos.game_id = game_data.id
AND videos.id = video_ratings.video_id
GROUP BY videos.id, video_ratings.video_id
ORDER BY videos.date_added DESC LIMIT 10;
I am running this query to extract data from three tables video_ratings, game_data, videos...
Now the problem I'm facing is the result only shows the videos that have been rated (or are in table video_ratings) because of AND videos.id = video_ratings.video_id...
Is there any way that I can select the data for all videos and the result shows AVG(video_ratings.rating) as null if ratings for those videos is not present in the video_ratings table (or say none of the videos have been rated so the result must show 10 rows with AVG(video_ratings.rating) column as null ) ...
Thanks
Yeah, just use a left outer inner instead of an inner join (which is what you're doing). I'd also suggest you use the JOIN syntax instead. It's far clearer:
SELECT v.id, v.game_id, v.xbox360, v.ps3, v.pc, v.wii,
v.other, v.thumbnail, v.vid_info, v.sdvid, v.hdvid,
UNIX_TIMESTAMP(v.date_added), gd.name, AVG(vg.rating)
FROM videos v
LEFT JOIN game_data gd ON gd.id = v.game_id
LEFT JOIN video_ratings vr ON v.id = vr.video_id
GROUP BY videos.id, video_ratings.video_id
ORDER BY videos.date_added DESC LIMIT 10