how to use select sub query in other query MySQL - mysql

I am writing a mysql select sub query, that is working fine, it returns 2 column is there way to select only 1 column.
My query is
SELECT sum(fl.qunt) as qunt,(
SELECT GROUP_CONCAT( xp.id
SEPARATOR ',' )
FROM prdt AS xp
LEFT JOIN prdt_fac AS pf ON pf.fk_product_children = xp.rowid
WHERE pf.prdt_fat = p.id
AND pf.prdt_ch = 6953
GROUP BY pf.prdt_fat
LIMIT 0 , 1
) AS prdt_chd
FROM fac_log AS fl
LEFT JOIN fac AS f ON fl.fac = f.id
LEFT JOIN prdt AS p ON f.prdt = p.id
GROUP BY prod_child
ORDER BY fl.tms DESC
LIMIT 0 , 1
This return two column qunt and prdt_ch.
But i want only column in result qunt.
Is there any way, becuase inner select query is must be used to get correct result.
Main purpose of this query is that i have to use this query as sub query in an other query, in this condition it throws error "operand should contain 1 column"
Thanks in advance

just select qunt using your select query as a table (t)
select qunt from (
SELECT sum(fl.qunt) as qunt,(
SELECT GROUP_CONCAT( xp.id
SEPARATOR ',' )
FROM prdt AS xp
LEFT JOIN prdt_fac AS pf ON pf.fk_product_children = xp.rowid
WHERE pf.prdt_fat = p.id
AND pf.prdt_ch = 6953
GROUP BY pf.prdt_fat
LIMIT 0 , 1
) AS prdt_chd
FROM fac_log AS fl
LEFT JOIN fac AS f ON fl.fac = f.id
LEFT JOIN prdt AS p ON f.prdt = p.id
GROUP BY prod_child
ORDER BY fl.tms DESC
LIMIT 0 , 1 ) t

Related

Doctrine Select last record from second table matching with first table

I have tow tables, first table related to forms and second table relate to adviser.each adviser can add comment for a form.
I tried select some column of two tables. It was works i have last subject of second table (adviser table ) in my result .but i need first subject of second table(adviser table ) .
#DQL
SELECT
f.name,
f.title,
f.conditionResultFinal,
f.conditionResult,
f.formCode,
f.dateInsert,
f.id,
(a.idFormRequestProject),
a.subject as subjectAdvisor
FROM AdminBundle:FormRequestProject f
JOIN AdminBundle:Advisor a
WHERE a.idFormRequestProject = f.id
AND (f.conditionResultFinal = 0 OR f.conditionResult = 0)
AND f.displayStatus = 1
GROUP BY f.id
ORDER by a.id,f.id DESC
Finally i solve this problem .i deleted GROUP By .and add new where ...
SELECT f.name,f.title,f.conditionResultFinal,
f.conditionResult ,
f.formCode,f.dateInsert ,
f.id,(a.idFormRequestProject),
a.subject as subjectAdvisor
FROM AdminBundle:FormRequestProject f
Left JOIN AdminBundle:Advisor a WHERE f.id = a.idFormRequestProject AND a.id =
(SELECT Max (aa.id) FROM AdminBundle:Advisor aa WHERE a.idFormRequestProject =
aa.idFormRequestProject ORDER by aa.id ASC ) AND
(f.conditionResultFinal = 0 OR f.conditionResult = 0 ) AND f.displayStatus =1
ORDER by f.id DESC

Join between sub-queries in SQLAlchemy

In relation to the answer I accepted for this post, SQL Group By and Limit issue, I need to figure out how to create that query using SQLAlchemy. For reference, the query I need to run is:
SELECT t.id, t.creation_time, c.id, c.creation_time
FROM (SELECT id, creation_time
FROM thread
ORDER BY creation_time DESC
LIMIT 5
) t
LEFT OUTER JOIN comment c ON c.thread_id = t.id
WHERE 3 >= (SELECT COUNT(1)
FROM comment c2
WHERE c.thread_id = c2.thread_id
AND c.creation_time <= c2.creation_time
)
I have the first half of the query, but I am struggling with the syntax for the WHERE clause and how to combine it with the JOIN. Any one have any suggestions?
Thanks!
EDIT: First attempt seems to mess up around the .filter() call:
c = aliased(Comment)
c2 = aliased(Comment)
subq = db.session.query(Thread.id).filter_by(topic_id=122098).order_by(Thread.creation_time.desc()).limit(2).offset(2).subquery('t')
subq2 = db.session.query(func.count(1).label("count")).filter(c.id==c2.id).subquery('z')
q = db.session.query(subq.c.id, c.id).outerjoin(c, c.thread_id==subq.c.id).filter(3 >= subq2.c.count)
this generates the following SQL:
SELECT t.id AS t_id, comment_1.id AS comment_1_id
FROM (SELECT count(1) AS count
FROM comment AS comment_1, comment AS comment_2
WHERE comment_1.id = comment_2.id) AS z, (SELECT thread.id AS id
FROM thread
WHERE thread.topic_id = :topic_id ORDER BY thread.creation_time DESC
LIMIT 2 OFFSET 2) AS t LEFT OUTER JOIN comment AS comment_1 ON comment_1.thread_id = t.id
WHERE z.count <= 3
Notice the sub-query ordering is incorrect, and subq2 somehow is selecting from comment twice. Manually fixing that gives the right results, I am just unsure of how to get SQLAlchemy to get it right.
Try this:
c = db.aliased(Comment, name='c')
c2 = db.aliased(Comment, name='c2')
sq = (db.session
.query(Thread.id, Thread.creation_time)
.order_by(Thread.creation_time.desc())
.limit(5)
).subquery(name='t')
sq2 = (
db.session.query(db.func.count(1))
.select_from(c2)
.filter(c.thread_id == c2.thread_id)
.filter(c.creation_time <= c2.creation_time)
.correlate(c)
.as_scalar()
)
q = (db.session
.query(
sq.c.id, sq.c.creation_time,
c.id, c.creation_time,
)
.outerjoin(c, c.thread_id == sq.c.id)
.filter(3 >= sq2)
)

MySQL search query with multiple joins and subqueries running slow

I have the following query which is actually within a stored procedure, but I removed it as there is too much going on inside the stored procedure. Basically this is the end result which takes ages (more than a minute) to run and I know the reason why - as you will also see from looking at the result of the explain - but I just cannot get it sorted.
Just to quickly explain what this query is doing. It is fetching all products from companies that are "connected" to the company where li.nToObjectID = 37. The result also returns some other information about the other companies like its name, company id, etc.
SELECT DISTINCT
SQL_CALC_FOUND_ROWS
p.id,
p.sTitle,
p.sTeaser,
p.TimeStamp,
p.ExpiryDate,
p.InStoreDate,
p.sCreator,
p.sProductCode,
p.nRetailPrice,
p.nCostPrice,
p.bPublic,
c.id as nCompanyID,
c.sName as sCompany,
m.id as nMID,
m.sFileName as sHighResFileName,
m.nSize,
(
Select sName
FROM tblBrand
WHERE id = p.nBrandID
) as sBrand,
(
Select t.sFileName
FROM tblThumbnail t
where t.nMediaID = m.id AND
t.sType = "thumbnail"
) as sFileName,
(
Select t.nWidth
FROM tblThumbnail t
where t.nMediaID = m.id AND
t.sType = "thumbnail"
) as nWidth,
(
Select t.nHeight
FROM tblThumbnail t
where t.nMediaID = m.id AND
t.sType = "thumbnail"
) as nHeight,
IF (
(
SELECT COUNT(id) FROM tblLink
WHERE
sType = "company"
AND sStatus = "active"
AND nToObjectID = 37
AND nFromObjectID = u.nCompanyID
),
1,
0
) AS bLinked
FROM tblProduct p
INNER JOIN tblMedia m
ON (
m.nTypeID = p.id AND
m.sType = "product"
)
INNER JOIN tblUser u
ON u.id = p.nUserID
INNER JOIN tblCompany c
ON u.nCompanyID = c.id
LEFT JOIN tblLink li
ON (
li.sType = "company"
AND li.sStatus = "active"
AND li.nToObjectID = 37
AND li.nFromObjectID = u.nCompanyID
)
WHERE c.bActive = 1
AND p.bArchive = 0
AND p.bActive = 1
AND NOW() <= p.ExpiryDate
AND (
li.id IS NOT NULL
OR (
li.id IS NULL
AND p.bPublic = 1
)
)
ORDER BY p.TimeStamp DESC
LIMIT 0, 52
Click here to see the output for EXPLAIN. Sorry, just couldn't get the formatting correct.
http://i60.tinypic.com/2hdqjgj.png
And lastly the number of rows for all the tables in this query:
tblProducts
Count: 5392
tblBrand
Count: 194
tblCompany
Count: 368
tblUser
Count: 416
tblMedia
Count: 5724
tblLink
Count: 24800
tblThumbnail
Count: 22207
So I have 2 questions:
1. Is there another way of writing this query which might potentially speed it up?
2. What index combination do I need for tblProducts so that not all the rows are searched through?
UPDATE 1
This is the new query after removing the subqueries and making use of left joins instead:
SELECT DISTINCT DISTINCT
SQL_CALC_FOUND_ROWS
p.id,
p.sTitle,
p.sTeaser,
p.TimeStamp,
p.ExpiryDate,
p.InStoreDate,
p.sCreator,
p.sProductCode,
p.nRetailPrice,
p.nCostPrice,
p.bPublic,
c.id as nCompanyID,
c.sName as sCompany,
m.id as nMID,
m.sFileName as sHighResFileName,
m.nSize,
brand.sName as sBrand,
thumb.sFilename,
thumb.nWidth,
thumb.nHeight,
IF (
(
SELECT COUNT(id) FROM tblLink
WHERE
sType = "company"
AND sStatus = "active"
AND nToObjectID = 37
AND nFromObjectID = u.nCompanyID
),
1,
0
) AS bLinked
FROM tblProduct p
INNER JOIN tblMedia m
ON (
m.nTypeID = p.id AND
m.sType = "product"
)
INNER JOIN tblUser u
ON u.id = p.nUserID
INNER JOIN tblCompany c
ON u.nCompanyID = c.id
LEFT JOIN tblLink li
ON (
li.sType = "company"
AND li.sStatus = "active"
AND li.nToObjectID = 37
AND li.nFromObjectID = u.nCompanyID
)
LEFT JOIN tblBrand AS brand
ON brand.id = p.nBrandID
LEFT JOIN tblThumbnail AS thumb
ON (
thumb.nMediaID = m.id
AND thumb.sType = 'thumbnail'
)
WHERE c.bActive = 1
AND p.bArchive = 0
AND p.bActive = 1
AND NOW() <= p.ExpiryDate
AND (
li.id IS NOT NULL
OR (
li.id IS NULL
AND p.bPublic = 1
)
)
ORDER BY p.TimeStamp DESC
LIMIT 0, 52;
UPDATE 2
ALTER TABLE tblThumbnail ADD INDEX (nMediaID,sType) USING BTREE;
ALTER TABLE tblMedia ADD INDEX (nTypeID,sType) USING BTREE;
ALTER TABLE tblProduct ADD INDEX (bArchive,bActive,ExpiryDate,bPublic,TimeStamp) USING BTREE;
After doing the above changes the explain showed that it is now only searching through 1464 rows on tblProduct instead of 5392.
That's a big query with a lot going on. It's going to take a few steps of work to optimize it. I will take the liberty of just presenting a couple of steps.
First step. Can you get rid of SQL_CALC_FOUND_ROWS and still have your program work correctly? If so, do that. When you specify SQL_CALC_FOUND_ROWS it sometimes means the server has to delay sending you the first row of your resultset until the last row is available.
Second step. Refactor the dependent subqueries to be JOINs instead.
Here's how you might approach that. Part of your query looks like this...
SELECT DISTINCT SQL_CALC_FOUND_ROWS
p.id,
...
c.id as nCompanyID,
...
m.id as nMID,
...
( /* dependent subquery to be removed */
Select sName
FROM tblBrand
WHERE id = p.nBrandID
) as sBrand,
( /* dependent subquery to be removed */
Select t.sFileName
FROM tblThumbnail t
where t.nMediaID = m.id AND
t.sType = "thumbnail"
) as sFileName,
( /* dependent subquery to be removed */
Select t.nWidth
FROM tblThumbnail t
where t.nMediaID = m.id AND
t.sType = "thumbnail"
) as nWidth,
( /* dependent subquery to be removed */
Select t.nHeight
FROM tblThumbnail t
where t.nMediaID = m.id AND
t.sType = "thumbnail"
) as nHeight,
...
Try this instead. Notice how the brand and thumbnail dependent subqueries disappear. You had three dependent subqueries for the thumbnail; they can disappear into a single JOIN.
SELECT DISTINCT SQL_CALC_FOUND_ROWS
p.id,
...
brand.sName,
thumb.sFilename,
thumb.nWidth,
thumb.nHeight,
...
FROM tblProduct p
INNER JOIN tblMedia AS m ON (m.nTypeID = p.id AND m.sType = 'product')
... (other table joins) ...
LEFT JOIN tblBrand AS brand ON p.id = p.nBrandID
LEFT JOIN tblMedia AS thumb ON (t.nMediaID = m.id AND thumb.sType = 'thumbnail')
I used LEFT JOIN rather than INNER JOIN so MySQL will present NULL values if the joined rows are missing.
Edit
You're using a join pattern that looks like this:
JOIN sometable AS s ON (s.someID = m.id AND s.sType = 'string')
You seem to do this for a few tables. You probably can speed up the JOIN operations by creating compound indexes in those tables. For example, try adding the following index to tblThumbnail: (sType, nMediaID). You can do that with this DDL statement.
ALTER TABLE tblThumbnail ADD INDEX (sType, nMediaID) USING BTREE
You can do similar things to other tables with the same join pattern.

Difficult MySQL Statement

I've got this query but the result is wrong.
How can I use the min() statement and the Group by Statement so that I will get for each AthletenID the lowest DiszOrder?
Select
ar_Leistungen.`AthletenID`,
ar_Leistungen.`Leistung`,
ar_Leistungen.`Disziplin`,
ar_Leistungen.`Klasse`,
min(ar_Leistungen.`DiszOrder`),
ar_Athleten.`Vorname`,
ar_Athleten.`Jahrgang`,
ar_Wettkampf.`Wettkampfdatum`
from
ar_Leistungen,
ar_Athleten,
ar_Wettkampf
Where
ar_Athleten.ID = ar_Leistungen.AthletenID and
ar_Leistungen.WettkampfID = ar_Wettkampf.ID and
ar_Leistungen.`Disziplin` = '100' and
ar_Leistungen.`Leistung` > 0 and
(ar_Athleten.`Jahrgang` = '1995' or ar_Athleten.`Jahrgang` = '1994') and
ar_Wettkampf.`Wettkampfdatum` LIKE '%2013%'
Group By
AthletenID
Order by
DiszOrder Desc
Limit
0, 100
You can have a subquery which separately gets the lowest DiszOrder for each AthletenID and join it with the other table so you can freely get the other value of the columns.
SELECT a.AthletenID,
a.Leistung,
a.Disziplin,
ar_Leistungen.Klasse,
a.DiszOrder),
b.Vorname,
b.Jahrgang,
c.Wettkampfdatum
FROM ar_Leistungen a
INNER JOIN ar_Athleten b
ON b.ID = a.AthletenID
INNER JOIN ar_Wettkampf c
ON a.WettkampfID = c.ID
INNER JOIN
(
SELECT AthletenID, MIN(DiszOrder) DiszOrder
FROM ar_Leistungen
GROUP BY AthletenID
) d ON a.AthletenID = d.AthletenID AND
a.DiszOrder = d.DiszOrder
WHERE a.Disziplin = '100' AND
a.Leistung > 0 AND
(b.Jahrgang IN ('1995', '1994'))

How to write a select statement inside another select in SQL

Can anyone tell me what is wrong with this query?
it gives a syntax error near the 2nd select
SELECT b.mc_boxes_idmc_boxes,
t.idtitles,
t.title,
t.languages_idlanguages,
MAX(h.idtitle_history),
MAX(h.edition)
(SELECT h.preview, h.file WHERE h.idtitle_history = MAX(h.idtitle_history))
FROM mc_boxes_has_titles b
LEFT JOIN titles t ON b.titles_idtitles = t.idtitles
LEFT JOIN title_history h ON h.titles_idtitles = t.idtitles
WHERE b.mc_boxes_idmc_boxes = 12
AND h.edition IS NOT NULL
GROUP BY b.mc_boxes_idmc_boxes, idtitles
ORDER BY b.sortorder;
looks like you are missing a comma after MAX(h.edition)
SELECT b.mc_boxes_idmc_boxes,
t.idtitles,
t.title,
t.languages_idlanguages,
MAX(h.idtitle_history),
MAX(h.edition),
(SELECT h.preview, h.file WHERE h.idtitle_history = MAX(h.idtitle_history))
FROM mc_boxes_has_titles b
LEFT JOIN titles t ON b.titles_idtitles = t.idtitles
LEFT JOIN title_history h ON h.titles_idtitles = t.idtitles
WHERE b.mc_boxes_idmc_boxes = 12
AND h.edition IS NOT NULL
GROUP BY b.mc_boxes_idmc_boxes, idtitles
ORDER BY b.sortorder;
besides the comma, you are selecting two fields in your subquery
SELECT b.mc_boxes_idmc_boxes,
t.idtitles,
t.title,
t.languages_idlanguages,
MAX(h.idtitle_history),
MAX(h.edition),
(SELECT preview FROM title_history WHERE idtitle_history = MAX(h.idtitle_history)),
(SELECT [file] FROM title_history WHERE idtitle_history = MAX(h.idtitle_history))
FROM mc_boxes_has_titles b
LEFT JOIN titles t ON b.titles_idtitles = t.idtitles
LEFT JOIN title_history h ON h.titles_idtitles = t.idtitles
WHERE b.mc_boxes_idmc_boxes = 12
AND h.edition IS NOT NULL
GROUP BY b.mc_boxes_idmc_boxes, idtitles
ORDER BY b.sortorder;
Adding to bluefeet's answer, you may want to check for reserved words. "File" for example is a reserved word in sql server.
Alias it as a virtual table. Change something like
SELECT b.mc_boxes_idmc_boxes,
t.idtitles,
t.title,
t.languages_idlanguages,
MAX(h.idtitle_history),
MAX(h.edition)
(SELECT h.preview, h.file WHERE h.idtitle_history = MAX(h.idtitle_history))
FROM mc_boxes_has_titles b
LEFT JOIN titles t ON b.titles_idtitles = t.idtitles
LEFT JOIN title_history h ON h.titles_idtitles = t.idtitles
WHERE b.mc_boxes_idmc_boxes = 12
AND h.edition IS NOT NULL
GROUP BY b.mc_boxes_idmc_boxes, idtitles
ORDER BY b.sortorder) as virtual_column_alias;
Check this out. Hope this will work.