I tryed to find an answer for this based on other questions, but I couldn't implement the logic into my necessity.
I can easily get the informations I need, however I can't update a table with those informations.
I have selected all the necessary values using the following query:
select `roleid`,
(select count(`killerid`) from `kills` where `killerid`=`roleid`) as `kills`,
(select count(`corpseid`) from `kills` where `corpseid`=`roleid`) as `deaths`
from `characters`
So this query returns the character's ID with its respective kills and deaths number.
Now, I need to know: How can I update table "characters", setting rows "kills" and "deaths" to the returned values in the query?
Thank you for your time.
UPDATE characters c
LEFT JOIN
( SELECT killerid, count(*) as kill_num FROM kills GROUP BY killerid ) k1
ON c.roleid = k1.killerID
LEFT JOIN
( SELECT corpseid, count(*) as death_num FROM kills GROUP BY corpseid ) k2
ON c.roleid = k2.corpseID
SET c.kills = k1.kill_num, c.deaths = k2.death_num
Related
Let's assume I have 2 tables. One contains car manufacturer's names and their IDs, the second contains information about car models. I need to select few of them from the first table, but order them by quantity of linked from the second table data.
Currently, my query looks like this:
SELECT DISTINCT `manufacturers`.`name`,
`manufacturers`.`cars_link`,
`manufacturers`.`slug`
FROM `manufacturers`
JOIN `cars`
ON manufacturers.cars_link = cars.manufacturer
WHERE ( NOT ( `manufacturers`.`cars_link` IS NULL ) )
AND ( `cars`.`class` = 'sedan' )
ORDER BY (SELECT Count(*)
FROM `cars`
WHERE `manufacturers`.cars_link = `cars`.manufacturer) DESC
It was working ok for my table of scooters which size is few dozens of mb. But now i need to do the same thing for the cars table, which size is few hundreds megabytes. The problem is that the query takes very long time, sometimes it even causes nginx timeout. Also, i think, that i have all the necesary database indexes. Is there any alternative for the query above?
lets try to use subquery for your count instead.
select * from (
select distinct m.name, m.cars_link, m.slug
from manufacturers m
join cars c on m.cars_link=c.manufacturer
left join
(select count(1) ct, c1.manufacturer from manufacturers m1
inner join cars_link c2 on m1.cars_link=c2.manufacturer
where coalesce(m1.cars_link, '') != '' and c1.class='sedan'
group by c1.manufacturer) as t1
on t1.manufacturer = c.manufacturer
where coalesce(m.cars_link, '') != '' and c.class='sedan') t2
order by t1.ct
Everything in the following query results in one line for each invBlueprintTypes row with the correct information. But I'm trying to add something to it. See below the codeblock.
Select
blueprintType.typeID,
blueprintType.typeName Blueprint,
productType.typeID,
productType.typeName Item,
productType.portionSize,
blueprintType.basePrice * 0.9 As bpoPrice,
productGroup.groupName ItemGroup,
productCategory.categoryName ItemCategory,
blueprints.productionTime,
blueprints.techLevel,
blueprints.researchProductivityTime,
blueprints.researchMaterialTime,
blueprints.researchCopyTime,
blueprints.researchTechTime,
blueprints.productivityModifier,
blueprints.materialModifier,
blueprints.wasteFactor,
blueprints.maxProductionLimit,
blueprints.blueprintTypeID
From
invBlueprintTypes As blueprints
Inner Join invTypes As blueprintType On blueprints.blueprintTypeID = blueprintType.typeID
Inner Join invTypes As productType On blueprints.productTypeID = productType.typeID
Inner Join invGroups As productGroup On productType.groupID = productGroup.groupID
Inner Join invCategories As productCategory On productGroup.categoryID = productCategory.categoryID
Where
blueprints.techLevel = 1 And
blueprintType.published = 1 And
productType.marketGroupID Is Not Null And
blueprintType.basePrice > 0
So what I need to get in here is the following table with the columns below it so I can use the values timestamp and sort the entire result by profitHour
tablename: invBlueprintTypesPrices
columns: blueprintTypeID, timestamp, profitHour
I need this information with the following select in mind. Using a select to show my intention of the JOIN/in-query select or whatever that can do this.
SELECT * FROM invBlueprintTypesPrices
WHERE blueprintTypeID = blueprintType.typeID
ORDER BY timestamp DESC LIMIT 1
And I need the main row from table invBlueprintTypes to still show even if there is no result from the invBlueprintTypesPrices. The LIMIT 1 is because I want the newest row possible, but deleting the older data is not a option since history is needed.
If I've understood correctly I think I need a subquery select, but how to do that? I've tired adding the exact query that is above with a AS blueprintPrices after the query's closing ), but did not work with a error with the
WHERE blueprintTypeID = blueprintType.typeID
part being the focus of the error. I have no idea why. Anyone who can solve this?
You'll need to use a LEFT JOIN to check for NULL values in invBlueprintTypesPrices. To mimic the LIMIT 1 per TypeId, you can use the MAX() or to truly make sure you only return a single record, use a row number -- this depends on whether you can have multiple max time stamps for each type id. Assuming not, then this should be close:
Select
...
From
invBlueprintTypes As blueprints
Inner Join invTypes As blueprintType On blueprints.blueprintTypeID = blueprintType.typeID
Inner Join invTypes As productType On blueprints.productTypeID = productType.typeID
Inner Join invGroups As productGroup On productType.groupID = productGroup.groupID
Inner Join invCategories As productCategory On productGroup.categoryID = productCategory.categoryID
Left Join (
SELECT MAX(TimeStamp) MaxTime, TypeId
FROM invBlueprintTypesPrices
GROUP BY TypeId
) blueprintTypePrice On blueprints.blueprintTypeID = blueprintTypePrice.typeID
Left Join invBlueprintTypesPrices blueprintTypePrices On
blueprintTypePrice.TypeId = blueprintTypePrices.TypeId AND
blueprintTypePrice.MaxTime = blueprintTypePrices.TimeStamp
Where
blueprints.techLevel = 1 And
blueprintType.published = 1 And
productType.marketGroupID Is Not Null And
blueprintType.basePrice > 0
Order By
blueprintTypePrices.profitHour
Assuming you might have the same max time stamp with 2 different records, replace the 2 left joins above with something similar to this getting the row number:
Left Join (
SELECT #rn:=IF(#prevTypeId=TypeId,#rn+1,1) rn,
TimeStamp,
TypeId,
profitHour,
#prevTypeId:=TypeId
FROM (SELECT *
FROM invBlueprintTypesPrices
ORDER BY TypeId, TimeStamp DESC) t
JOIN (SELECT #rn:=0) t2
) blueprintTypePrices On blueprints.blueprintTypeID = blueprintTypePrices.typeID AND blueprintTypePrices.rn=1
You don't say where you are putting the subquery. If in the select clause, then you have a problem because you are returning more than one value.
You can't put this into the from clause directly, because you have a correlated subquery (not allowed).
Instead, you can put it in like this:
from . . .
(select *
from invBLueprintTypesPrices ibptp
where ibtp.timestamp = (select ibptp2.timestamp
from invBLueprintTypesPrices ibptp2
where ibptp.blueprintTypeId = ibptp2.blueprintTypeId
order by timestamp desc
limit 1
)
) ibptp
on ibptp.blueprintTypeId = blueprintType.TypeID
This identifies the most recent records for all the blueprintTypeids in the subquery. It then joins in the one that matches.
What I want to do is to set every patient its unique patient code which starts with 1 and it's not based on row id. Id only specifies order. Something like this:
patient_id patient_code
2 1
3 2
4 3
This is my query:
UPDATE patients p1
SET p1.patient_code = (
SELECT COUNT( * )
FROM patients p2
WHERE p2.patient_id <= p1.patient_id
)
But it is throwing error:
#1093 - You can't specify target table 'p1' for update in FROM clause
I found this thread: Mysql error 1093 - Can't specify target table for update in FROM clause.But I don't know how to apply approved answer this to work with subquery WHERE which is necessary for COUNT.
UPDATE
patients AS p
JOIN
( SELECT
p1.patient_id
, COUNT(*) AS cnt
FROM
patients AS p1
JOIN
patients AS p2
ON p2.patient_id <= p1.patient_id
GROUP BY
p1.patient_id
) AS g
ON g.patient_id = p.patient_id
SET
p.patient_code = g.cnt ;
I found working solution, but this is just workaround:
SET #code=0;
UPDATE patients SET patient_code = (SELECT #code:=#code+1 AS code)
Try this,
UPDATE patients p1 INNER JOIN
(
SELECT COUNT(*) as count,patient_id
FROM patients
group by patient_id
)p2
SET p1.patient_code=p2.count
WHERE p2.patient_id <= p1.patient_id
SQL_LIVE_DEMO
Thanks to Mari's answer I found a solution to my similar problem. But I wanted to add a bit of an explanation which for me at first wasn't too clear from his answer.
What I wanted to do would have been as simple as the following:
UPDATE my_comments AS c
SET c.comment_responses = (
SELECT COUNT(c1.*) FROM my_comments AS c1
WHERE c.uid = c.parent_uid
);
Thanks to Mari I then found the solution on how to achieve this without running into the error You can't specify target table 'p1' for update in FROM clause:
UPDATE my_comments AS c
INNER JOIN (
SELECT c1.parent_uid, COUNT(*) AS cnt
FROM my_comments AS c1
WHERE c1.parent_uid <> 0
GROUP BY c1.parent_uid
) AS c2
SET c.comment_responses = c2.cnt
WHERE c2.parent_uid = c.uid;
My problems before getting to this solution were 2:
the parent_uid field doesn't always contain an id of a parent which is why I added the WHERE statement in the inner join
I didn't quite understand why I would need the GROUP BY until I executed the SELECT statement on it's own and the answer is: because COUNT groups the result and really counts everything. In order to prevent this behavior the GROUP BY is needed. In my case I didn't have to group it by uid though but the parent_uid to get the correct count. If I grouped it by uid the COUNT would always be 1 but the parent_uid existed multiple times in the result. I suggest you check the SELECT statement on it's own to check if it's the result you expect before you execute the full UPDATE statement.
Can anyone see what is wrong with the below query?
When I run it I get:
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use
near 'a where a.CompetitionID = Competition.CompetitionID' at line 8
Update Competition
Set Competition.NumberOfTeams =
(
SELECT count(*) as NumberOfTeams
FROM PicksPoints
where UserCompetitionID is not NULL
group by CompetitionID
) a
where a.CompetitionID = Competition.CompetitionID
The main issue is that the inner query cannot be related to your where clause on the outer update statement, because the where filter applies first to the table being updated before the inner subquery even executes. The typical way to handle a situation like this is a multi-table update.
Update
Competition as C
inner join (
select CompetitionId, count(*) as NumberOfTeams
from PicksPoints as p
where UserCompetitionID is not NULL
group by CompetitionID
) as A on C.CompetitionID = A.CompetitionID
set C.NumberOfTeams = A.NumberOfTeams
Demo: http://www.sqlfiddle.com/#!2/a74f3/1
Thanks, I didn't have the idea of an UPDATE with INNER JOIN.
In the original query, the mistake was to name the subquery, which must return a value and can't therefore be aliased.
UPDATE Competition
SET Competition.NumberOfTeams =
(SELECT count(*) -- no column alias
FROM PicksPoints
WHERE UserCompetitionID is not NULL
-- put the join condition INSIDE the subquery :
AND CompetitionID = Competition.CompetitionID
group by CompetitionID
) -- no table alias
should do the trick for every record of Competition.
To be noticed :
The effect is NOT EXACTLY the same as the query proposed by mellamokb, which won't update Competition records with no corresponding PickPoints.
Since SELECT id, COUNT(*) GROUP BY id will only count for existing values of ids,
whereas a SELECT COUNT(*) will always return a value, being 0 if no records are selected.
This may, or may not, be a problem for you.
0-aware version of mellamokb query would be :
Update Competition as C
LEFT join (
select CompetitionId, count(*) as NumberOfTeams
from PicksPoints as p
where UserCompetitionID is not NULL
group by CompetitionID
) as A on C.CompetitionID = A.CompetitionID
set C.NumberOfTeams = IFNULL(A.NumberOfTeams, 0)
In other words, if no corresponding PickPoints are found, set Competition.NumberOfTeams to zero.
For the impatient:
UPDATE target AS t
INNER JOIN (
SELECT s.id, COUNT(*) AS count
FROM source_grouped AS s
-- WHERE s.custom_condition IS (true)
GROUP BY s.id
) AS aggregate ON aggregate.id = t.id
SET t.count = aggregate.count
That's #mellamokb's answer, as above, reduced to the max.
You can check your eav_attributes table to find the relevant attribute IDs for each image role, such as;
Then you can use those to set whichever role to any other role for all products like so;
UPDATE catalog_product_entity_varchar AS `v` INNER JOIN (SELECT `value`,`entity_id` FROM `catalog_product_entity_varchar` WHERE `attribute_id`=86) AS `j` ON `j`.`entity_id`=`v`.entity_id SET `v`.`value`=j.`value` WHERE `v`.attribute_id = 85 AND `v`.`entity_id`=`j`.`entity_id`
The above will set all your 'base' roles to the 'small' image of the same product.
I am trying to create an update query and making little progress in getting the right syntax.
The following query is working:
SELECT t.Index1, t.Index2, COUNT( m.EventType )
FROM Table t
LEFT JOIN MEvents m ON
(m.Index1 = t.Index1 AND
m.Index2 = t.Index2 AND
(m.EventType = 'A' OR m.EventType = 'B')
)
WHERE (t.SpecialEventCount IS NULL)
GROUP BY t.Index1, t.Index2
It creates a list of triplets Index1,Index2,EventCounts.
It only does this for case where t.SpecialEventCount is NULL. The update query I am trying to write should set this SpecialEventCount to that count, i.e. COUNT(m.EventType) in the query above. This number could be 0 or any positive number (hence the left join). Index1 and Index2 together are unique in Table t and they are used to identify events in MEvent.
How do I have to modify the select query to become an update query? I.e. something like
UPDATE Table SET SpecialEventCount=COUNT(m.EventType).....
but I am confused what to put where and have failed with numerous different guesses.
I take it that (Index1, Index2) is a unique key on Table, otherwise I would expect the reference to t.SpecialEventCount to result in an error.
Edited query to use subquery as it didn't work using GROUP BY
UPDATE
Table AS t
LEFT JOIN (
SELECT
Index1,
Index2,
COUNT(EventType) AS NumEvents
FROM
MEvents
WHERE
EventType = 'A' OR EventType = 'B'
GROUP BY
Index1,
Index2
) AS m ON
m.Index1 = t.Index1 AND
m.Index2 = t.Index2
SET
t.SpecialEventCount = m.NumEvents
WHERE
t.SpecialEventCount IS NULL
Doing a left join with a subquery will generate a giant
temporary table in-memory that will have no indexes.
For updates, try avoiding joins and using correlated
subqueries instead:
UPDATE
Table AS t
SET
t.SpecialEventCount = (
SELECT COUNT(m.EventType)
FROM MEvents m
WHERE m.EventType in ('A','B')
AND m.Index1 = t.Index1
AND m.Index2 = t.Index2
)
WHERE
t.SpecialEventCount IS NULL
Do some profiling, but this can be significantly faster in some cases.
my example
update card_crowd as cardCrowd
LEFT JOIN
(
select cc.id , count(1) as num
from card_crowd cc LEFT JOIN
card_crowd_r ccr on cc.id = ccr.crowd_id
group by cc.id
) as tt
on cardCrowd.id = tt.id
set cardCrowd.join_num = tt.num;