I am running the below query
(
select Game.GameID, Game.season, GamePlaysPlayers.playerID
from (select Game.GameID, Game.season, GamePlaysPlayers.playerID
from Game
inner join GamePlaysPlayers on Game.GameID = GamePlaysPlayers.GameID
where Game.season = '20082009'
)
inner join (
select Game.GameID, Game.season, GamePlaysPlayers.playerID
from Game
inner join GamePlaysPlayers on Game.GameID = GamePlaysPlayers.GameID
where Game.season = '20182019'
) on Game.GameID = GamePlaysPlayers.GameID
);
And I got the error "Every derived table must have its own alias".
The error message is pretty clear.
If you refer to MySQL documentation https://dev.mysql.com/doc/refman/8.0/en/derived-tables.html, a name for every derived table is mandatory so you must include a AS clause to both subqueries.
I guess that the names would be "Game" for the first subquery and "GamePlaysPlayers" for the second one.
Related
My mysql query is too slow and i don't know how to optimize it. My webapp cant load this query because take too much time to run and the webserver have a limit time to get the result.
SELECT rc.trial_id,
rc.created,
rc.date_registration,
rc.agemin_value,
rc.agemin_unit,
rc.agemax_value,
rc.agemax_unit,
rc.exclusion_criteria,
rc.study_design,
rc.expanded_access_program,
rc.number_of_arms,
rc.enrollment_start_actual,
rc.target_sample_size,
(select name from repository_institution where id = rc.primary_sponsor_id) as
primary_sponsor,
(select label from vocabulary_studytype where id = rc.study_type_id) as study_type,
(select label from vocabulary_interventionassigment where id =
rc.intervention_assignment_id) as intervention_assignment,
(select label from vocabulary_studypurpose where id = rc.purpose_id) as study_purpose,
(select label from vocabulary_studymasking where id = rc.masking_id) as study_mask,
(select label from vocabulary_studyallocation where id = rc.allocation_id) as
study_allocation,
(select label from vocabulary_studyphase where id = rc.phase_id) as phase,
(select label from vocabulary_recruitmentstatus where id = rc.recruitment_status_id) as
recruitment_status,
GROUP_CONCAT(vi.label)
FROM
repository_clinicaltrial rc
inner JOIN repository_clinicaltrial_i_code rcic ON rcic.clinicaltrial_id = rc.id JOIN
vocabulary_interventioncode vi ON vi.id = rcic.interventioncode_id
GROUP BY rc.id;
Using inner join instead join could be a solution?
Changing to JOINs vs continuous selects per every row will definitely improve. Also, since you are using MySQL, using the keyword "STRAIGHT_JOIN" tells MySQL to do the query in the order I provided. Since your "rc" table is the primary and all the others are lookups, this will make MySQL use it in that context rather than hoping some other lookup table be the basis of the rest of the joins.
SELECT STRAIGHT_JOIN
rc.trial_id,
rc.created,
rc.date_registration,
rc.agemin_value,
rc.agemin_unit,
rc.agemax_value,
rc.agemax_unit,
rc.exclusion_criteria,
rc.study_design,
rc.expanded_access_program,
rc.number_of_arms,
rc.enrollment_start_actual,
rc.target_sample_size,
ri.name primary_sponsor,
st.label study_type,
via.label intervention_assignment,
vsp.label study_purpose,
vsm.label study_mask,
vsa.label study_allocation,
vsph.label phase,
vrs.label recruitment_status,
GROUP_CONCAT(vi.label)
FROM
repository_clinicaltrial rc
JOIN repository_clinicaltrial_i_code rcic
ON rc.id = rcic.clinicaltrial_id
JOIN vocabulary_interventioncode vi
ON rcic.interventioncode_id = vi.id
JOIN repository_institution ri
on rc.primary_sponsor_id = ri.id
JOIN vocabulary_studytype st
on rc.study_type_id = st.id
JOIN vocabulary_interventionassigment via
on rc.intervention_assignment_id = via.id
JOIN vocabulary_studypurpose vsp
ON rc.purpose_id = vsp.id
JOIN vocabulary_studymasking vsm
ON rc.masking_id = vsm.id
JOIN vocabulary_studyallocation vsa
ON rc.allocation_id = vsa.id
JOIN vocabulary_studyphase vsph
ON rc.phase_id = vsph.id
JOIN vocabulary_recruitmentstatus vrs
ON rc.recruitment_status_id = vrs.id
GROUP BY
rc.id;
One final note. You are using a GROUP BY and applying to the GROUP_CONCAT() which is ok. However, proper group by says you need to group by all non-aggregate columns, which in this case is every other column in the list. You may know this, and the fact the lookups will be the same based on the "rc" associated columns, but its not good practice to do so.
Your joins and subqueries are probably not the problem. Assuming you have correct indexes on the tables, then these are fast. "Correct indexes" means that the id column is the primary key -- a very reasonable assumption.
My guess is that the GROUP BY is the performance issue. So, I would suggest structuring the query with no `GROUP BY:
select . . .
(select group_concat(vi.label)
from repository_clinicaltrial_i_code rcic
vocabulary_interventioncode vi
on vi.id = rcic.interventioncode_id
where rcic.clinicaltrial_id = rc.id
)
from repository_clinicaltrial rc ;
For this, you want indexes on:
repository_clinicaltrial_i_code(clinicaltrial_id, interventioncode_id)
vocabulary_interventioncode(id, label)
I am getting a "... not unique table/alias 'plots' ..." error when trying to run the following UPDATE statement:
UPDATE homestead.plots
INNER JOIN homestead.graphs
ON homestead.drivers.id = homestead.graphs.driver_id
INNER JOIN homestead.plots
ON homestead.plots.graph_id = homestead.graphs.id
SET homestead.plots.yAxis = homestead.plots.yAxis + 3.4
WHERE homestead.graphs.name = "DI";
Even though the below SELECT statement works fine, and returns the results I want:
SELECT homestead.graphs.driver_id, homestead.drivers.MarketingNo, homestead.graphs.name, homestead.plots.xAxis, homestead.plots.yAxis
FROM homestead.drivers
INNER JOIN homestead.graphs
ON homestead.drivers.id = homestead.graphs.driver_id
INNER JOIN homestead.plots
ON homestead.plots.graph_id = homestead.graphs.id
WHERE homestead.graphs.name = "DI";
Any ideas how to fix my UPDATE statement to work? I've done a lot of research online but cannot understand why this doesn't work.
There are several flaws with your UPDATE statement, for example:
table plots is referenced twice (in the UPDATE and in a JOIN) and not aliased (this is causing the error that you are getting)
you are referring to column id in table homestead.graphs, but this table is not part of any join
Based on your SELECT query, I would try and phrase your UPDATE as follows:
UPDATE homestead.plots p
INNER JOIN homestead.graphs g ON p.graph_id = g.id AND g.name = "DI"
INNER JOIN homestead.drivers d ON d.id = g.driver_id
SET p.yAxis = p.yAxis + 3.4
So, this query is currently used in a webshop to retrieve technical data about articles.
It has served its purpose fine except the amount of products shown have increased lately resulting in unacceptable long loading times for some categories.
For one of the worst pages this (and some other queries) get requested about 80 times.
I only recently learned that MySQL does not optimize sub-queries that don't have a depending parameter to only run once.
So if someone could help me with one of the queries and explain how you can replace the in's and exists's to joins, i will probably be able to change the other ones myself.
select distinct criteria.cri_id, des_texts.tex_text, article_criteria.acr_value, article_criteria.acr_kv_des_id
from article_criteria, designations, des_texts, criteria, articles
where article_criteria.acr_cri_id = criteria.cri_id
and article_criteria.acr_art_id = articles.art_id
and articles.art_deliverystatus = 1
and criteria.cri_des_id = designations.des_id
and designations.des_lng_id = 9
and designations.des_tex_id = des_texts.tex_id
and criteria.cri_id = 328
and article_criteria.acr_art_id IN (Select distinct link_art.la_art_id
from link_art, link_la_typ
where link_art.la_id = link_la_typ.lat_la_id
and link_la_typ.lat_typ_id = 17484
and link_art.la_ga_id IN (Select distinct link_ga_str.lgs_ga_id
from link_ga_str, search_tree
where link_ga_str.lgs_str_id = search_tree.str_id
and search_tree.str_type = 1
and search_tree.str_id = 10132
and EXISTS (Select *
from link_la_typ
where link_la_typ.lat_typ_id = 17484
and link_ga_str.lgs_ga_id = link_la_typ.lat_ga_id)))
order by article_criteria.acr_value
I think this one is the main badguy with sub-sub-sub-queries
I just noticed i can remove the last exist and still get the same results but with no increase in speed, not part of the question though ;) i'll figure out myself whether i still need that part.
Any help or pointers are appreciated, if i left out some useful information tell me as well.
I think this is equivalent:
SELECT DISTINCT c.cri_id, dt.tex_text, ac.acr_value, ac.acr_kv_des_id
FROM article_criteria AS ac
JOIN criteria AS c ON ac.acr_cri_id = c.cri_id
JOIN articles AS a ON ac.acr_art_id = a.art_id
JOIN designations AS d ON c.cri_des_id = d.des_id
JOIN des_texts AS dt ON dt.tex_id = d.des_tex_id
JOIN (SELECT distinct la.la_art_id
FROM link_art AS la
JOIN link_la_typ AS llt ON la.la_id = llt.lat_la_id
JOIN (SELECT DISTINCT lgs.lgs_ga_id
FROM link_ga_str AS lgs
JOIN search_tree AS st ON lgs.lgs_str_id = st.str_id
JOIN link_la_typ AS llt ON lgs.lgs_ga_id = llt.lat_ga_id
WHERE st.str_type = 1
AND st.str_id = 10132
AND llt.lat_typ_id = 17484) AS lgs
ON la.la_ga_id = lgs.lgs_ga_id
WHERE llt.lat_typ_id = 17484) AS la
ON ac.acr_art_id = la.la_art_id
WHERE a.art_deliverystatus = 1
AND d.des_lng_id = 9
AND c.cri_id = 328
ORDER BY ac.acr_value
All the IN <subquery> clauses can be replaced with JOIN <subquery>, where you then JOIN on the column being tested equaling the column returned by the subquery. And the EXISTS test is converted to a join with the table, moving the comparison in the subquery's WHERE clause into the ON clause of the JOIN.
It's probably possible to flatten the whole thing, instead of joining with subqueries. But I suspect performance will be poor, because this won't reduce the temporary tables using DISTINCT. So you'll get combinatorial explosion in the resulting cross product, which will then have to be reduced at the end with the DISTINCT at the top.
I've converted all the implicit joins to ANSI JOIN clauses, to make the structure clearer, and added table aliases to make things more readable.
In general, you can convert a FROM tab1 WHERE ... val IN (SELECT blah) to a join like this.
FROM tab1
JOIN (
SELECT tab1_id
FROM tab2
JOIN tab3 ON whatever = whatever
WHERE whatever
) AS sub1 ON tab1.id = sub1.tab1_id
The JOIN (an inner join) will drop the rows that don't match the ON condition from your query.
If your tab1_id values can come up duplicate from your inner query, use SELECT DISTINCT. But don't use SELECT DISTINCT unless you need to; it is costly to evaluate.
Here is a brief explanation of what I'm trying to accomplish; my query follows below.
There are 4 tables and 1 view which are relevant for this particular query (sorry the names look messy, but they follow a strict convention that would make sense if you saw the full list):
Performances may have many Performers, and those associations are stored in PPerformer. Fans can have favorites, which are stored in Favorite_Performer. The _UpcomingPerformances view contains all the information needed to display a user-friendly list of upcoming performances.
My goal is to select all the data from _UpcomingPerformances, then include one additional column that specifies whether the given Performance has a Performer which the Fan added as their favorite. This involves selecting the list of Performers associated with the Performance, and also the list of Performers who are in Favorite_Performer for that Fan, and intersecting the two arrays to determine if anything is in common.
When I execute the below query, I get the error #1054 - Unknown column 'up.pID' in 'where clause'. I suspect it's somehow related to a misuse of Correlated Subqueries but as far as I can tell what I'm doing should work. It works when I replace up.pID (in the WHERE clause of t2) with a hard-coded number, and yes, pID is an existing column of _UpcomingPerformances.
Thanks for any help you can provide.
SELECT
up.*,
CASE
WHEN EXISTS (
SELECT * FROM (
SELECT RID FROM Favorite_Performer
WHERE FanID = 107
) t1
INNER JOIN
(
SELECT r.ID as RID
FROM PPerformer pr
JOIN Performer r ON r.ID = pr.Performer_ID
WHERE pr.Performance_ID = up.pID
) t2
ON t1.RID = t2.RID
)
THEN "yes"
ELSE "no"
END as pText
FROM
_UpcomingPerformances up
The problem is scope related. The nested Selects make the up table invisible inside the internal select. Try this:
SELECT
up.*,
CASE
WHEN EXISTS (
SELECT *
FROM Favorite_Performer fp
JOIN Performer r ON fp.RID = r.ID
JOIN PPerformer pr ON r.ID = pr.Performer_ID
WHERE fp.FanID = 107
AND pr.Performance_ID = up.pID
)
THEN 'yes'
ELSE 'no'
END as pText
FROM
_UpcomingPerformances up
I have a query in MySQL and I am making a crystal report by using this.
Now inside the query i have a column called scan_mode and it is coming from gfi_transaction table. This scan_mode I am using in report to suppress some sections. But some times this value is coming null for some transaction ids.
So now I want to take this scan_mode as separate query so that it will work.
Can any one please help how I can modify the below query to take only scan_mode column.
SELECT
cc.cost_center_code AS cccde,
cc.name AS ccnme,gf.scan_mode,
cc.cost_center_id AS ccid,
site.name AS siteme,
crncy.currency_locale AS currency_locale,
cntry.language AS LANGUAGE,
cntry.country_name AS cntrynm,
crncy.decimal_digits AS rnd,
gf.transaction_no AS Serial_No,
brnd.name AS brand_name,
rsn.description AS reason,
gf.comment AS COMMENT,
ts.status_description AS STATUS,
DATE_FORMAT(gf.created_date,'%d/%m/%Y') AS created_date,
gf.created_by AS created_by,
IFNULL(gf.approval_no,'Not authorized') AS Trans_no,
gf.approved_date AS approval_dt,
gf.approved_by AS approved_by,gf.status AS status1,
IFNULL(loc.cost_center_code,cc.cost_center_code) AS cur_location,
gf.document_ref_no,gf.document_ref_type,
,DATE_FORMAT(document_ref_date1,'%d/%m/%Y')) AS invoice_no
FROM
gfi_transaction gf
INNER JOIN gfi_instruction gfn ON (gf.transaction_id=gfn.transaction_id)
INNER JOIN gfi_document_instruction doc ON (gf.ref_transaction_no = doc.document_instruction_id)
INNER JOIN reason rsn ON (gf.reason_id = rsn.reason_id)
INNER JOIN gfi_status ts ON (gf.status = ts.gfi_status_id)
INNER JOIN transaction_type tt ON (gf.transaction_type_id = tt.transaction_type_id)
INNER JOIN brand brnd ON(gf.brand_id=brnd.brand_id)
-- cc details
INNER JOIN cost_center cc ON (brnd.parent_brand = cc.brand_id OR gf.brand_id = cc.brand_id)
INNER JOIN site site ON(cc.site_id = site.site_id)
INNER JOIN country cntry ON (site.country_id = cntry.country_id)
INNER JOIN currency crncy ON (cntry.currency_id=crncy.currency_id)
LEFT OUTER JOIN alshaya_location_details loc ON
(gf.brand_id = loc.brand_id AND loc.cost_center_id = gf.cost_centre_id)
LEFT OUTER JOIN alshaya_location_details locto ON
(locto.cost_center_id = gf.from_cost_center_id)
WHERE
gf.transaction_id='{?TransID}'
AND rsn.transaction_type_id IN (10,11,14)
wow, that's a big query. I ran across a similar problem in a query i was building and found the if syntax to be a solution to my problem. This was also answered in this question: MYSQL SELECT WITHIN IF Statement
$psdb->query = "SELECT count, s.classid,
if (k.sic != k.siccode, k.siccode, s.siccode) as siccode,
if (k.sic != k.siccode, k.sicdesc, s.sicdesc) as sicdesc,
if (k.sic != k.siccode, k.sicslug, s.sicslug) as sicslug
FROM ...
It looks like scan_mode column comes from "gfi_transaction" table which seems to be primary table in your query. If you get null for this column then it means your table itself have NULL value for this column. Taking that separately in a query wont solve your problem. Try replacing null with a default value and handle it in code. You can add default value instead of NULL by using ifnull(scan_mode, 'default')