I have two tables, one for downloads and one for uploads. They are almost identical but with some other columns that differs them. I want to generate a list of stats for each date for each item in the table.
I use these two queries but have to merge the data in php after running them. I would like to instead run them in a single query, where it would return the columns from both queries in each row grouped by the date. Sometimes there isn't any download data, only upload data, and in all my previous tries it skipped the row if it couldn't find log data from both rows.
How do I merge these two queries into one, where it would display data even if it's just available in one of the tables?
SELECT DATE(upload_date_added) as upload_date, SUM(upload_size) as upload_traffic, SUM(upload_files) as upload_files
FROM packages_uploads
WHERE upload_date_added BETWEEN '2011-10-26' AND '2011-11-16'
GROUP BY upload_date
ORDER BY upload_date DESC
SELECT DATE(download_date_added) as download_date, SUM(download_size) as download_traffic, SUM(download_files) as download_files
FROM packages_downloads
WHERE download_date_added BETWEEN '2011-10-26' AND '2011-11-16'
GROUP BY download_date
ORDER BY download_date DESC
I want to get result rows like this:
date, upload_traffic, upload_files, download_traffic, download_files
All help appreciated!
Your two queries can be executed and then combined with the UNION cluase along with an extra field to identify Uploads and Downloads on separate lines:
SELECT
'Uploads' TransmissionType,
DATE(upload_date_added) as TransmissionDate,
SUM(upload_size) as TransmissionTraffic,
SUM(upload_files) as TransmittedFileCount
FROM
packages_uploads
WHERE upload_date_added BETWEEN '2011-10-26' AND '2011-11-16'
GROUP BY upload_date
ORDER BY upload_date DESC
UNION
SELECT
'Downloads',
DATE(download_date_added),
SUM(download_size),
SUM(download_files)
FROM packages_downloads
WHERE download_date_added BETWEEN '2011-10-26' AND '2011-11-16'
GROUP BY download_date
ORDER BY download_date DESC;
Give it a Try !!!
What you're asking can only work for rows that have the same add date for upload and download. In this case I think this SQL should work:
SELECT
DATE(u.upload_date_added) as date,
SUM(u.upload_size) as upload_traffic,
SUM(u.upload_files) as upload_files,
SUM(d.download_size) as download_traffic,
SUM(d.download_files) as download_files
FROM
packages_uploads u, packages_downloads d
WHERE u.upload_date_added = d.download_date_added
AND u.upload_date_added BETWEEN '2011-10-26' AND '2011-11-16'
GROUP BY date
ORDER BY date DESC
Without knowing the schema is hard to give the exact answer so please see the following as a concept not a direct answer.
You could try left join, im not sure if the table package exists but the following may be food for thought
SELECT
p.id,
up.date as upload_date
dwn.date as download_date
FROM
package p
LEFT JOIN package_uploads up ON
( up.package_id = p.id WHERE up.upload_date = 'etc' )
LEFT JOIN package_downloads dwn ON
( dwn.package_id = p.id WHERE up.upload_date = 'etc' )
The above will select all the packages and attempt to join and where the value does not join it will return null.
There is number of ways that you can do this. You can join using primary key and foreign key. In case if you do not have relationship between tables,
You can use,
LEFT JOIN / LEFT OUTER JOIN
Returns all records from the left table and the matched
records from the right table. The result is NULL from the
right side when there is no match.
RIGHT JOIN / RIGHT OUTER JOIN
Returns all records from the right table and the matched
records from the left table. The result is NULL from the left
side when there is no match.
FULL OUTER JOIN
Return all records when there is a match in either left or right table records.
UNION
Is used to combine the result-set of two or more SELECT statements.
Each SELECT statement within UNION must have the same number of,
columns The columns must also have similar data types The columns in,
each SELECT statement must also be in the same order.
INNER JOIN
Select records that have matching values in both tables. -this is good for your situation.
INTERSECT
Does not support MySQL.
NATURAL JOIN
All the column names should be matched.
Since you dont need to update these you can create a view from joining tables then you can use less query in your PHP. But views cannot update. And you did not mentioned about relationship between tables. Because of that I have to go with the UNION.
Like this,
CREATE VIEW checkStatus
AS
SELECT
DATE(upload_date_added) as upload_date,
SUM(upload_size) as upload_traffic,
SUM(upload_files) as upload_files
FROM packages_uploads
WHERE upload_date_added BETWEEN '2011-10-26' AND '2011-11-16'
GROUP BY upload_date
ORDER BY upload_date DESC
UNION
SELECT
DATE(download_date_added) as download_date,
SUM(download_size) as download_traffic,
SUM(download_files) as download_files
FROM packages_downloads
WHERE download_date_added BETWEEN '2011-10-26' AND '2011-11-16'
GROUP BY download_date
ORDER BY download_date DESC
Then anywhere you want to select you just need one line:
SELECT * FROM checkStatus
learn more.
Related
I have two tables table_entries and table_images.
table_images holds a series of images for any single item in table_entries
both tables are organized by a vid which is essentially an item id.
Not all items in table_entries will have an image, while others may have multiple images
What I am trying to construct is a query to only select items from table_entries that have an image, specifically 10 entries that have an image, which i've built as follows:
SELECT * FROM table_entries
INNER JOIN table_images ON (table_entries.vid = table_images.vid)
WHERE (model LIKE '%apple%' OR ext LIKE '%apple%')
ORDER BY lastupdated DESC LIMIT 0,10
EDIT: lastupdated, model and ext all belong to table_entries, in fact all sorting, selecting, etc.. is done based on table_entries
The problem with the above query is that it is successfully only picking items with images, but if a single item has 10 images, then it will return the 10 rows as item #1 with each of its images as individual rows. The intention is to have 10 distinct items, and limit the join to only 1 image for each item from table_entries
So I want to somehow limit the join to 1 row for the entire join.
I've searched for the answer here on SO and found so many good answers to this question (MySQL INNER JOIN select only one row from second table, MySQL JOIN with LIMIT 1 on joined table) , however they all use aliases for selecting the tables.
I could use alias and fix my query, but there is a TON of PHP code that I would have to change to deal with the aliased table names.
Is it possible to fix my query to only select 1 row from the joined table without the use of aliases?
You can do:
select *
from (
select *,
row_number() over(partition by i.vid order by i.updated) as rn
from table_entries e
join table_images i on i.vid = e.vid
where e.model like '%apple%' or e.ext like '%apple'
) x
where rn = 1 -- this is the key filter
order by lastupdated desc
limit 0, 10
Please consider this query could be awfully slow due to the use of LIKE '%text%' in the search condition, specially if the table table_entries has millions of rows.
I am using the following query to join tables together and it seems to be working although I can't really understand why:
SELECT
listing.name,
biggestLot.price,
FROM Listings listing
LEFT JOIN Lots biggestLot ON biggestLot.lotNumber = (
SELECT lotNumber
FROM Lots
WHERE lotNumber IN
(
SELECT lotNumber
FROM Listings listingInner
WHERE listingInner.listingNumber = listing.listingNumber
)
ORDER BY size DESC
LIMIT 1
)
GROUP BY listing.listingNumber
The context is that each "Listing" is associated with one or more "Lots" through a "lotNumber" field. The tables aren't normalized; i.e. for any given Listing, there may be one or more rows in the "Listings" table that have duplicate values for all fields except for "lotNumber". The intent of the above query is to find the price of the biggest Lot associated with each Listing.
The inner SELECT is getting the largest Lot for a given Listing and I understand how that works. What I don't understand is how the LEFT JOIN merges the biggestLot result with the outer SELECT Listings query. I'm not specifying an ON field to combine the two tables so how does it know how to combine the results?
You could can use window functions along with the JOIN:
SELECT l.name, lo.price,
FROM Listings l LEFT JOIN
(SELECT lo.*,
ROW_NUMBER() OVER (PARITION BY lo.lotNumber ORDER BY lo.size DESC) as seqnum
FROM Lots lo
) lo
USING (lotNmber);
I have two tables, group and groupAccess. One contains information for each "group", and the other contains all the times a group is accessed, including it's unique ID and timestamp.
My goal is to order all groups by the most recent time they were accessed.
I've got half way there, this query allows me to get all the groups in the correct order, however there are duplicate groups that I need to remove.
SELECT a.*
FROM groups a
INNER JOIN groupAccess b ON a.group_id = b.group_access_id
ORDER BY access_time DESC
I've tried using GROUP BY or DISTINCT, however this breaks the (currently) correct order of the groups. How can I fix this?
Use max() and GROUP BY to find the latest access time of each group, and then join that table with group. That is:
SELECT
a.*
, b.last_access_time
FROM
groups a
INNER JOIN (
select
group_access_id
, max(access_time) as last_access_time
from groupAccess
group by
group_access_id
) b ON a.group_id = b.group_access_id
ORDER BY b.last_access_time DESC
I am doing a sub-query join to another table as I wanted to be able to sort the results I got back with it, I only need the first row but I need them ordered in a certain way so I would get the lowest id.
I tried adding LIMIT 1 to this but then the full query returned 0 results; so now it has no limit and in the EXPLAIN I have two rows showing they are using the full 10k+ rows of the auction_media table.
I wrote it this way to avoid having to query the auction_media table for each row separately, but now I'm thinking that this way isn't that great if it has to use the whole auction_media table?
Which way is better? The way I have it or querying the auction_media table separately? ...or is there a better way!?
Here is the code:
SELECT
a.auction_id,
a.name,
media.media_url
FROM
auctions AS a
LEFT JOIN users AS u ON u.user_id=a.owner_id
INNER JOIN ( SELECT media_id,media_url,auction_id
FROM auction_media
WHERE media_type=1
AND upload_in_progress=0
ORDER BY media_id ASC
) AS media
ON a.auction_id=media.auction_id
WHERE a.hpfeat=1
AND a.active=1
AND a.approved=1
AND a.closed=0
AND a.creation_in_progress=0
AND a.deleted=0
AND (a.list_in='auction' OR u.shop_active='1')
GROUP BY a.auction_id;
Edit: Through my testing, using the above query seems like it would be the much faster method overall; however I worry if that will still be the case when the auction_media table grows to like 1M rows or something.
edit: As stated in the comments - DISTINCT is not required because the auctions table can only be associated with (at most) one user table row and one row in the inner query.
You may want to try this. The outer query's GROUP BY is replaced with DISTINCT since you don't have any aggregate function. The inner query, was replaced by a query to find the smallest media_id per auction_id, then JOINed back to get the media_url. (Since I didn't know if the media_id and auction_id were a composite unique key, I used the same WHERE clause to help eliminate potential duplicates.)
SELECT
a.auction_id,
a.name,
auction_media.media_url
FROM auctions AS a
LEFT JOIN users AS u
ON u.user_id=a.owner_id
INNER JOIN (SELECT auction_id, MIN(media_id) AS media_id
FROM auction_media
WHERE media_type=1
AND upload_in_progress=0
GROUP BY auction_id) AS media
ON a.auction_id=media.auction_id
INNER JOIN auction_media
ON auction_media.media_id = media.media_id
AND auction_media.auction_id = media.auction_id
AND auction_media.media_type=1
AND auction_media.upload_in_progress=0
WHERE a.hpfeat=1
AND a.active=1
AND a.approved=1
AND a.closed=0
AND a.creation_in_progress=0
AND a.deleted=0
AND (a.list_in='auction' OR u.shop_active='1');
I'm trying to compare two set of resutls aving hard time to undesrtand how subqueries work and if they are efficient. I'm not gonna explain all my tables, but just think i have apair of arrays...i might do it in php but i wonder if i can do it in mysql right away...
this is my query to check how many items user 1 has in lists he owns
SELECT DISTINCT *
FROM list_tb
INNER JOIN item_to_list_tb
ON list_tb.list_id = item_to_list_tb.list_id
WHERE list_tb.user_id = 1
ORDER BY item_to_list_tb.item_id DESC
this is my query to check how many items user 2 has in lists he owns
SELECT DISTINCT *
FROM list_tb
INNER JOIN item_to_list_tb
ON list_tb.list_id = item_to_list_tb.list_id
WHERE list_tb.user_id = 1
ORDER BY item_to_list_tb.item_id DESC
now the problem is that i would intersect those results to check how many item_id they have in common...
thanks!!!
Unfortunately, MySQL does not support the Intersect predicate. However, one way to accomplish that goal would be to exclude List_Tb.UserId from your Select and Group By and then count by distinct User_Id:
Select ... -- everything except List_Tb.UserId
From List_Tb
Inner Join Item_To_List_Tb
On List_Tb.List_Id = Item_To_List_Tb.List_Id
Where List_Tb.User_Id In(1,2)
Group By ... -- everything except List_Tb.UserId
Having Count( Distinct List_Tb.User_Id ) = 2
Order By item_to_list_tb.item_id Desc
Obviously you would replace the ellipses with the actual columns you want to return and on which you wish to group.