This is such a simple problem but for some reason I cannot get my head round it today.
I have two entities:- title and product each respectively named tbl_title and tbl_product. Each title can have many products.
The product table has a field called unwanted which can be either null, 0 or 1.
I wish to select all titles based on where all products (ALL) have unwanted set to 1. So in other words I wish to select the parent based upon all children filling a certain condition. So if a title has one product that is unwanted but another that is not I do not wish for this title to enter the result set.
When I try this the most I get out of my head is:
SELECT * FROM `tbl_title`
left join tbl_product on tbl_product.title_id = tbl_title.id
where tbl_product.unwanted = 1
group by tbl_title.id
Which obviously does not work.
So how do I code such a query?
select * from tbl_title
where id not in (select title_id from tbl_product where unwanted = 0)
In English, this query eliminates all titles that have a wanted product.
From a style point of view, it would be better to call your column wanted, because unwanted = 0 is a double-negative of wanted = 1. It's always easier to get your head around positives.
SELECT t.id
FROM `tbl_title` t
left join tbl_product p on p.title_id = t.id
group by t.id
having sum(p.unwanted = 0 or p.unwanted is null) = 0
Try using a subquery like this:
SELECT * FROM `tbl_title` AS t
WHERE EXISTS (SELECT 1 FROM products WHERE title_id = t.id AND unwanted = 1)
AND NOT EXISTS (SELECT 1 FROM products WHERE title_id = t.id AND (unwanted = 0 OR unwanted IS NULL))
Just for the fields in title table
SELECT *
FROM `tbl_title` AS t
JOIN tbl_product AS v ON t.id = v.title_id
WHERE NOT EXISTS(
SELECT *
FROM tbl_product
WHERE (t.id = title_id)
AND (unwanted = 0 OR unwanted IS NULL)
GROUP BY t.id
Related
I'm trying to build a search function but the current table structure troubles me.
So each row identifies a 'tag' association with an audio ID.
TABLE audio_tag_assoc example
I get the name of each tag id by joining the table tag_association.
TABLE tag_association example
Therefore I need to get all the audio ids that match two or even three tag names.
What I tried is the following but you can probably tell that it doesn't work. I would have later added a join in between those parentheses to change the IDs of the IN with strings.
SELECT *
FROM audio_tag_assoc a
JOIN tag_association b ON a.tag = b.id
WHERE a.audio = (SELECT *
FROM audio_tag_assoc
WHERE tag IN (2,3)
)
Initially I tried having b.name = 'Male' AND b.name = 'Film' but of course, that's not how mysql WHERE clause works.
Do :
SELECT
*
FROM
audio_tag_assoc
INNER JOIN
tag_association ON audio_tag_assoc.tag = tag_association.id
WHERE
audio_tag_assoc.id IN (SELECT
a.id
FROM audio_tag_assoc a
WHERE
a.tag IN (2,3)
GROUP BY
a.audio
HAVING COUNT(a.id) >= 2
);
I've got two tables, for example: Teacher and Pupil and table LastViewedPupil with fields who watched him and when (teacherId & pupilId). So I want to return the list of Pupils that was ordered by last viewed date, but there are not all pupils inside LastViewedPupil, but last few for example, I want to show after that ordered by date all left records no matter in wich order, how can I do that?
I can do without last part like
select * from Pupil as p, (
select * from LastViewedPupil lvp where lvp.teacherId = 5 ORDER BY lastViewDate
) as lvp where lvp.pupilId = p.pupilId;
Or should I add corresponding records in LastViewDatePupil for all pupils or need to Join table itself (sounds awkward)?
You should try this one:
SELECT p.*
LEFT JOIN LastViewedPupil lvp ON p.id = lvp
WHERE lvp.teacher_id = 5
ORDER BY lvp.lastViewDate DESC
I'm not sure if that query puts NULL at the beginning or at the end. If that doesn't order the results properly, try this other. I used a CASE for reordering data
SELECT p.*,
CASE WHEN lvp.lvp.lastViewDate IS NULL THEN 1 ELSE 0, END AS notNullfirst FROM Pupil p
LEFT JOIN LastViewedPupil lvp ON p.id = lvp
WHERE lvp.teacher_id = 5
ORDER BY notNullfirst, lvp.lastViewDate DESC
I have made Q & A website that a questions can have tags in it and the user can subscribe to tags they want. So, I have create tag page for list all tags and count all questions and users who subscribed to these tags.I found similar question here but it more complex for me.
The code below is SQL I'm trying and it seems very slow for query times. I want SQL below is to write by using JOIN/LEFT JOIN/RIGHT JOIN I think it will be faster. But I have no idea.
SQL
select tag.*,
(select count(*) from taggedquestion where taggedquestion.tagid = tag.id) questionCount,
(select count(*) from tagsubscription where tagsubscription.tagid = tag.id) userCount
from tag order by tag.id asc
Tags page
Tag name question count user count
----------------------------------------------------------------
computer 12 5
science 10 3
travel 6 2
programing 18 3
... ... ...
... ... ...
This is your query:
select tag.*,
(select count(*) from taggedquestion where taggedquestion.tagid = tag.id and ids = '0'
) as questionCount,
(select count(*) from tagsubscription where tagsubscription.tagid = tag.id and ids = '0'
) as userCount
from tag
order by tag.id asc;
This is a reasonable query. Probably what you need for performance are the following indexes (if you don't already have them):
taggedquestion(tagid, ids)
tagsubscription(tagid, ids)
tag(id)
You probably already have the last one, because id is presumably a primary key on the tag table.
On your second posted query, you are missing SELECT and so getting the posted error. Your second query should look like below
SELECT tag.*,
( SELECT COUNT(*) FROM taggedquestion
LEFT JOIN tag ON tag.id = taggedquestion.tagid
and taggedquestion.ids = '0') AS postCount,
(SELECT COUNT(*) FROM tagsubscription
LEFT JOIN tag ON tag.id = tagsubscription.tagid
and tagsubscription.ids = '0') AS userCount
FROM tag
Try like this then using SUM with CASE condition. Since you haven't shown your tables structure or sample data; can't say for sure but you might want to group by the taggedquestion.ids like
SELECT tag.*,
( SELECT SUM(CASE WHEN taggedquestion.ids = '0' THEN 1 ELSE 0 END)
FROM taggedquestion
INNER JOIN tag
ON tag.id = taggedquestion.tagid
GROUP BY taggedquestion.ids) AS postCount,
(SELECT SUM(CASE WHEN tagsubscription.ids = '0' THEN 1 ELSE 0 END)
FROM tagsubscription
INNER JOIN tag
ON tag.id = tagsubscription.tagid
GROUP BY tagsubscription.ids) AS userCount
FROM tag
This has been asked in different ways before, but I can't seem to get something that works for what I need exactly.
The goal here is to make a search query that returns Photos based on tags that are selected. Many tags can be applied to the filter simultaneously, which would need to make it so that the query only returns photos that have ALL of the tags selected. Think of any major web shop where you are narrowing down results after performing a basic keyword search.
Table1: Photos
ID|Title|Description|URL|Created
Table2: PhotosTagsXref
ID|PhotoId|TagId
Table3: PhotosTags
ID|Title|Category
What I have:
SELECT p.* FROM `PhotosTagsXref` AS pt
LEFT JOIN `Photos` AS p ON p.`ID` = pt.`PhotoId`
LEFT JOIN `PhotosTags` AS t ON pt.`TagId` = t.`ID`
WHERE p.`Description` LIKE "%test%" AND
????
GROUP BY p.`ID`
ORDER BY p.`Created` DESC LIMIT 20
The ???? is where I've tried a bunch of things, but stumped. Problem is I can easily find a result set that contains photos with one tag or another, but if applying 2, 3, or 4 tags we'd need to only return photos that have entries for all of those tags in the database. I think this will involve combining result sets but not 100% sure.
Example:
Photo 1 Tags: Blue, White, Red
Photo 2 Tags: Blue
Searching for a photo with tags of 'blue' returns both photos, searching for a photo with tags of 'blue' and 'white' returns only Photo 1.
Supposing the requested set of tags is (red,blue) you can do:
SELECT * FROM `Photos`
WHERE `Description` LIKE "%test%"
AND `ID` IN (
SELECT pt.`PhotoId` FROM `PhotosTagsXref` AS pt
JOIN `PhotosTags` AS t ON pt.`TagId` = t.`ID`
WHERE t.Title in ('red','blue') /* your set here */
GROUP BY pt.`PhotoId` HAVING COUNT(DISTINCT t.`TagId`)=2 /* # of tags */
)
ORDER BY `Created` DESC LIMIT 20
Apparently, the tag set needs to be created dynamically, as well as its count.
Note: I'm counting DISTINCT TagIDs because I don't know your table's constraints. If PhotosTagsXRef had a PK/UNIQUE (PhotoId,TagId) and PhotosTags had a PK/UNIQUE (TagId), then COUNT(*) would suffice.
Admittedly a bit ugly. But assuming that PhotosTags.Category has the 'Blue', 'White', etc, try something along this line.
SELECT p.*
From `Photos` AS p
WHERE p.`Description` LIKE "%test%" AND
AND Exists
( Select 1 FROM `PhotosTagsXref` AS pt
Inner JOIN `PhotosTags` AS t ON pt.`TagId` = t.`ID`
Where pt.`PhotoId` = p.`ID`
And t.Category = 'FirstCatToSearch'
)
AND Exists
( Select 1 FROM `PhotosTagsXref` AS pt
Inner JOIN `PhotosTags` AS t ON pt.`TagId` = t.`ID`
Where pt.`PhotoId` = p.`ID`
And t.Category = 'SecondCatToSearch'
)
AND Exists
( ...
)
...
SELECT p.* FROM `PhotosTagsXref` AS pt
LEFT JOIN `Photos` AS p ON p.`ID` = pt.`PhotoId`
LEFT JOIN `PhotosTags` AS t ON pt.`TagId` = t.`ID`
inner join (select PhotoId from PhotosTagsXref
LEFT JOIN `PhotosTags` AS t
ON pt.`TagId` = t.`ID`
where (t.title = 'cond 1' or t.title = 'cond 2' ...)
--where t.title in (list condition) **this works as well**
having count(1) = (count of conditions) ) filter
on filter.photoID = pt.PhotoID
WHERE p.`Description` LIKE "%test%"
GROUP BY p.`ID`
ORDER BY p.`Created` DESC LIMIT 20
That should work, I made some assumptions on what column to use for the filter and joins, you may need to retool...the inner join functions as a filter and should pull out only records that have the number of matches equal to the total of the number of matches submitted. Now you just need a language to plug in those conditions and condition count values.
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.