I am currently trying to get data from 2 tables with a LEFT JOIN having an unknow value.
I tried using LEFT JOIN but it didn't work.
Here is my code example :
SELECT
cc.shid,
cc.user,
ts.type,
sum(cc.qty1) + sum(cc.qty2) as qty_tot,
COUNT(cc.id) as nb
FROM
content_c cc
LEFT JOIN
(SELECT
s.shid,
s.type
FROM
tab_s s
LIMIT 1
) as ts ON ts.shid = cc.shid
WHERE
cc.time_i like '2019-01%'
GROUP BY
cc.user,
ts.type
With that query it will never work : ts will contain the first occurence of tab_s regardless of cc.shid. I wonder if there is a way to make this :
LEFT JOIN
(SELECT
s.shid,
s.type
FROM
tab_s s
WHERE
s.shid = cc.shid
LIMIT 1
) as ts ON ts.shid = cc.shid
Any idea ? Is there a pointer notion in SQL or something like ? Like I can use &cc.shid, or #cc.shid ?
Note that doing the following :
LEFT JOIN tab_s ts ON ts.shid = cc.shid
Will make my request to take more than 1 minute to display results. And I cannot set an index in tab_s.shid aswell as cc.shid as its have multiple occurences.
Please keep in mind that content_c can have multiple occurence of cc.shid, that why I need to take only the first result (LIMIT 1). It's important.
Use a correlated subquery:
SELECT cc.shid, cc.user, cc.type,
SUM(cc.qty1) + SUM(cc.qty2) as qty_tot,
COUNT(cc.id) as nb
FROM (SELECT cc.*,
(SELECT s.type
FROM tab_s s
WHERE ts.shid = cc.shid
LIMIT 1
) as type
FROM content_c cc
) cc
WHERE cc.time_i >= '2019-01-01' AND
cc.time_i < '2019-02-01'
GROUP BY cc.shid, cc.user, cc.type;
Notes:
The use of LIMIT with no ORDER BY is suspicious. Why would there be duplicates in the underlying table?
Your date comparisons are bad. Use date/time functions when working with date/time values. Don't use string functions.
The GROUP BY should include all non-aggregated columns in the SELECT.
As discussed in the question comments, Can you please try this script and see if it meets your requirements? This will return a row per ID in "content_c" table with the GROUP BY impact.
SELECT
cc.shid,
cc.user,
ts.type,
sum(cc.qty1) + sum(cc.qty2) as qty_tot,
COUNT(cc.id) as nb
FROM content_c cc
LEFT JOIN
(
SELECT DISTINCT s.shid, s.type FROM tab_s s
) AS ts ON ts.shid = cc.shid
WHERE cc.time_i like '2019-01%'
GROUP BY cc.shid,cc.user,ts.type
Related
I have the SQL command:
SELECT
vinculo.id,
data start,
count(*) title
from
atendimento_regulacao
join vinculo on vinculo.id = atendimento_regulacao.vinculo_id
where data = '2019-07-02'
group by vinculo.usuario_id, atendimento_regulacao.data
The result is empty because not exists none record on where data = '2019-07-02'
How to show the id like below?
id | start | title
1 | |
You can use a CROSS JOIN to generate the rows and LEFT JOIN to bring in the results:
select v.id, d.dte as start, count(ar.vinculo_id) as num_title
from (select '2019-07-02' as dte) d cross join
vinculo v left join
atendimento_regulacao ar
on v.id = ar.vinculo_id and ar.data = d.dte
group by v.id, d.dte;
If you really want to aggregate by v.usuario_id, then include it in both the select and group by.
Notes:
The structure of the query easily extends to multiple dates.
The GROUP BY uses the same columns in the SELECT.
Table aliases make the query easier to write and to read.
Qualify all column references in a query that has more than one table reference.
The COUNT() uses a column from ar so it can return 0.
For the specific case of a single date, you can use conditional aggregation:
select v.id, '2019-07-02' as start,
count(ar.vinculo_id) as num_title
from vinculo v left join
atendimento_regulacao ar
on v.id = ar.vinculo_id and ar.data = '2019-07-02'
group by v.id;
Use RIGHT JOIN, and convert your count to the one below, otherwise it shows zero whenever didn't find to count anything.
SELECT v.id, a.data start,
case when count(*) is null then null end title
FROM atendimento_regulacao a
RIGHT JOIN vinculo v
ON v.id = a.vinculo_id
AND a.data = '2019-07-02'
GROUP BY v.usuario_id, a.data;
Demo
I have 3 tables, namely - areas, works and jobs.
areas works jobs
----- ----- -----
area_id work_id area_id (FK)
area_name task work_id (FK)
area_type app_area status
updated_at
I'm trying to select the total list of areas cross joined with works such that I have all the permutations for areas vs works, then have the LATEST status of that combination, if it exists. I want distinct rows for each area_id-work_id combination.
I put together the below query statement but some rows have statuses displayed as NULL when they actually exist. My guess is there's something wrong with my inner SELECT statement but try as I may, I could not get it to work, any idea what's wrong with my statement?
SELECT area_name, works.task, jobs.status
FROM areas
CROSS JOIN works ON works.work_id = works.work_id
LEFT JOIN jobs ON jobs.status = (SELECT jobs.status FROM jobs ORDER BY jobs.updated_at DESC LIMIT 1) AND
(jobs.work_id = works.work_id AND jobs.area_id = areas.area_id)
WHERE works.app_area = 'zone' AND areas.area_type = 'zone'
ORDER BY areas.area_id, works.work_id, jobs.updated_at;
Your logic for the last status should be using the date not the status. The logic looks like this:
SELECT a.area_name, w.task, j.status
FROM areas a CROSS JOIN
works w LEFT JOIN
jobs j
ON j.work_id = w.work_id AND j.area_id = a.area_id AND
j.updated_at = (SELECT MAX(j2.updated_at)
FROM jobs j2
WHERE j2.work_id = w.work_id AND j2.area_id = a.area_id
)
WHERE w.app_area = 'zone' AND a.area_type = 'zone'
ORDER BY a.area_id, w.work_id, j.updated_at;
This also fixes some other problems, such as having an ON clause with CROSS JOIN.
If you want to solve it by your own query then please replace this line in the left join sub query
SELECT j.status FROM jobs j ORDER BY jobs.updated_at DESC LIMIT 1
Using Gordon Solution, I think this is another way you can do it. you'll have to test to see which way works faster for you.
SELECT a.area_name, w.task, (SELECT MAX(j2.updated_at)
FROM jobs j2
WHERE j2.work_id = w.work_id AND j2.area_id = a.area_id
) status
FROM areas a CROSS JOIN
works w LEFT JOIN
jobs j
ON j.work_id = w.work_id AND j.area_id = a.area_id
WHERE w.app_area = 'zone' AND a.area_type = 'zone'
ORDER BY a.area_id, w.work_id, j.updated_at;
I have been researching this for hours and the best code that I have come up with is this from an example i found on overstack. I have been through several derivations but the following is the only query that returns the correct data, the problem is it takes over 139s (more than 2 minutes) to return only 30 rows of data. Im stuck. (life_p is a 'likes'
SELECT
logos.id,
logos.in_gallery,
logos.active,
logos.pubpriv,
logos.logo_name,
logos.logo_image,
coalesce(cc.Count, 0) as CommentCount,
coalesce(lc.Count, 0) as LikeCount
FROM logos
left outer join(
select comments.logo_id, count( * ) as Count from comments group by comments.logo_id
) cc on cc.logo_id = logos.id
left outer join(
select life_p.logo_id, count( * ) as Count from life_p group by life_p.logo_id
) lc on lc.logo_id = logos.id
WHERE logos.active = '1'
AND logos.pubpriv = '0'
GROUP BY logos.id
ORDER BY logos.in_gallery desc
LIMIT 0, 30
I'm not sure whats wrong. If i do them singularly meaningremove the coalece and one of the joins:
SELECT
logos.id,
logos.in_gallery,
logos.active,
logos.pubpriv,
logos.logo_name,
logos.logo_image,
count( * ) as lc
FROM logos
left join life_p on life_p.logo_id = logos.id
WHERE logos.active = '1'
AND logos.pubpriv = '0'
GROUP BY logos.id
ORDER BY logos.in_gallery desc
LIMIT 0, 30
that runs in less than half a sec ( 2-300 ms )....
Here is a link to the explain: https://logopond.com/img/explain.png
MySQL has a peculiar quirk that allows a group by clause that does not list all non-aggregating columns. This is NOT a good thing and you should always specify ALL non-aggregating columns in the group by clause.
Note, when counting over joined tables it is useful to know that the COUNT() function ignores NULLs, so for a LEFT JOIN where NULLs can occur don't use COUNT(*), instead use a column from within the joined table and only rows from that table will be counted. From these points I would suggest the following query structure.
SELECT
logos.id
, logos.in_gallery
, logos.active
, logos.pubpriv
, logos.logo_name
, logos.logo_image
, COALESCE(COUNT(cc.logo_id), 0) AS CommentCount
, COALESCE(COUNT(lc.logo_id), 0) AS LikeCount
FROM logos
LEFT OUTER JOIN comments cc ON cc.logo_id = logos.id
LEFT OUTER JOIN life_p lc ON lc.logo_id = logos.id
WHERE logos.active = '1'
AND logos.pubpriv = '0'
GROUP BY
logos.id
, logos.in_gallery
, logos.active
, logos.pubpriv
, logos.logo_name
, logos.logo_image
ORDER BY logos.in_gallery DESC
LIMIT 0, 30
If you continue to have performance issues then use a execution plan and consider adding indexes to suit.
You can create some indexes on the joining fields:
ALTER TABLE table ADD INDEX idx__tableName__fieldName (field)
In your case will be something like:
ALTER TABLE cc ADD INDEX idx__cc__logo_id (logo_id);
I dont really like it because ive always read that sub queries are bad and that joins perform better under stress, but in this particular case subquery seems to be the only way to pull the correct data in under half a sec consistently. Thanks for the suggestions everyone.
SELECT
logos.id,
logos.in_gallery,
logos.active,
logos.pubpriv,
logos.logo_name,
logos.logo_image,
(Select COUNT(comments.logo_id) FROM comments
WHERE comments.logo_id = logos.id) AS coms,
(Select COUNT(life_p.logo_id) FROM life_p
WHERE life_p.logo_id = logos.id) AS floats
FROM logos
WHERE logos.active = '1' AND logos.pubpriv = '0'
ORDER BY logos.in_gallery desc
LIMIT ". $start .",". $pageSize ."
Also you can create a mapping tables to speed up your query try:
CREATE TABLE mapping_comments AS
SELECT
comments.logo_id,
count(*) AS Count
FROM
comments
GROUP BY
comments.logo_id
) cc ON cc.logo_id = logos.id
Then change your code
left outer join(
should become
inner join mapping_comments as mp on mp.logo_id =cc.id
Then each time a new comment are added to the cc table you need to update your mapping table OR you can create a stored procedure to do it automatically when your cc table changes
I'm doing a union of two different tables and ordering by the date column. Shouldn't the union make the two date columns one? It's giving me the error: #1052 - Column 'date' in order clause is ambiguous
Am I missing something here? Here's the query:
SELECT comments.*, postid, prayers.date AS date, prayers.type AS type
FROM comments
LEFT JOIN prayers USING (postid)
WHERE comments.username = 'hoodleehoo'
AND comments.new = 1
AND comments.first = 1
AND (comments.type = 'prayer' or comments.type = 'answer')
AND prayers.privacy != 'hidden'
UNION
SELECT comments.*, postid, posts.date AS date, comments.type AS type
FROM comments
LEFT JOIN posts USING (postid)
WHERE comments.username = 'hoodleehoo'
AND comments.new = 1
AND comments.first = 1
AND (comments.type = 'post' or comments.type = 'shared')
ORDER BY date
UPDATE:
I guess you can't use "date". That must be a reserved word. I changed date to "date2" and it's working fine. I'm sure I'm not the only one who will run into this!
For your query to work as it is now the last line should be ORDER BY posts.date. And by your question i'm thinking you are actually trying to do this
SELECT * FROM ( SELECT comments.*, postid, prayers.date AS DATE2, prayers.type AS type
FROM comments
LEFT JOIN prayers USING (postid)
WHERE comments.username = 'hoodleehoo'
AND comments.new = 1
AND comments.first = 1
AND comments.type = 'prayer'
AND prayers.privacy != 'hidden'
UNION
SELECT comments.*, postid, posts.date AS DATE2, comments.type AS type
FROM comments
LEFT JOIN posts USING (postid)
WHERE comments.username = 'hoodleehoo'
AND comments.new = 1
AND comments.first = 1
AND comments.type != 'prayer')
ORDER BY DATE2
The "ambiguous" messaging is an aliasing issue.
As for ordering the results of a union. It is answered here: How to order by with union
Check Mark Robinson's answer. I think it will suit your needs.
you have to specify tablename with date column
ORDER BY tablename.[date]
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.