I wanna select from 2 tables.
In first table I want select all data.
In second table I want select only "name".
'edition' in first table it's 'id' in second table.
I wrote sql code, but it isn't work:
SELECT link, title, description, imgUri, vkCount, fbCount, twCount, edition
FROM articles
RIGHT JOIN SELECT name
FROM editions
WHERE id = articles.edition
ORDER BY (vkCount + fbCount + twCount) DESC
LIMIT 0, $count
Structure: http://i.imgur.com/bMcokCp.png
Looks pretty close but you have the JOIN syntax a little wrong. Use ON for a join and only one SELECT clause
SELECT link, title, description, imgUri, vkCount, fbCount, twCount, edition, name
FROM articles
JOIN editions ON id = articles.edition
ORDER BY (vkCount + fbCount + twCount) DESC
LIMIT 0, $count
Related
I have a table. Table has structure of id, name, color, product_id.
And the table has multiple rows with the same product_id.
With SQL query from PHP file - I would like to choose only one, the oldest, row. (The first one that was added to the current table).
What query should I use or approach?
Thank you!
Just making up a bit of mockup data ... Note the notes I put in. And I trust it's a newer version of MySQL, as the older ones did not support ROW_NUMBER() OVER() .
Here goes:
WITH
-- input ... you *need* a timestamp to identify the oldest ---
indata(id, name, color, product_id,ts) AS (
SELECT 1,'Arthur','blue' ,42,TIMESTAMP'2021-01-31 17:45:00'
UNION ALL SELECT 1,'Arthur','blue' ,42,TIMESTAMP'2021-01-31 17:50:00'
UNION ALL SELECT 1,'Arthur','blue' ,42,TIMESTAMP'2021-01-31 17:55:00'
UNION ALL SELECT 1,'Arthur','blue' ,42,TIMESTAMP'2021-01-31 18:00:00'
UNION ALL SELECT 2,'Ford' ,'red' ,42,TIMESTAMP'2021-01-31 17:45:00'
UNION ALL SELECT 2,'Ford' ,'blue', 42,TIMESTAMP'2021-01-31 17:50:00'
UNION ALL SELECT 2,'Ford' ,'green',42,TIMESTAMP'2021-01-31 17:55:00'
UNION ALL SELECT 2,'Ford' ,'cyan' ,42,TIMESTAMP'2021-01-31 18:00:00'
)
,
-- select all, plus a rank, on which you will filter outside ..
with_rank AS (
SELECT
*
, ROW_NUMBER() OVER(PARTITION BY id ORDER BY ts) AS rnk
FROM indata
)
SELECT
id
, name
, color
, product_id
, ts
FROM with_rank
WHERE rnk = 1
id|name |color|product_id|ts
1|Arthur|blue |42 |2021-01-31 17:45:00
2|Ford |red |42 |2021-01-31 17:45:00
One method is a correlated subquery:
select t.*
from t
where t.id = (select min(t2.id)
from t t2
where t2.product_id = t.product_id
);
This assumes that id is incrementing with each insertion. If not, you have no way of knowing what the "oldest" row is. SQL tables represent unordered sets, so there is no "oldest" row unless a column contains that information.
SELECT * FROM TableName WHERE product_id = ProductID ORDER BY product_id LIMIT 1;
I have a table that I use to store some systematically chosen "serial numbers" for each product that is bought...
The problem is, a CSV was uploaded that I believe contained some duplicate "serial numbers", which means that when the application tries to modify a row, it may not be modifying the correct one.
I need to be able to query the database and get all rows that are a double of the serial_number column. It should look something like this:
ID, serial_number, meta1, meta2, meta3
3, 123456, 0, 2, 4
55, 123456, 0, 0, 0
6, 345678, 0, 1, 2
99, 345678, 0, 1, 2
So as you can see, I need to be able to see both the original row and the duplicate row and all of it's columns of data ... this is so I can compare them and determine what data is now inconsistent.
Some versions of MySQL implement in with a subquery very inefficiently. A safe alternative is a join:
SELECT t.*
FROM t join
(select serial_number, count(*) as cnt
from t
group by serial_number
) tsum
on tsum.serial_number = t.serial_number and cnt > 1
order by t.serial_number;
Another alternative is to use an exists clause:
select t.*
from t
where exists (select * from t t2 where t2.serial_number = t.serial_number and t2.id <> t.id)
order by t.serial_number;
Both these queries (as well as the one proposed by #fthiella) are standard SQL. Both would benefit from an index on (serial_number, id).
SELECT *
FROM
yourtable
WHERE
serial_number IN (SELECT serial_number
FROM yourtable
GROUP BY serial_number
HAVING COUNT(*)>1)
ORDER BY
serial_number, id
I want to make a fast table structure for news site with php and mysql. My database structure is ID, title, content, cat_ids (; separedet IDs of categories - ;5;10;15;20;), active, publish_date.
I want to make a fast query to select news from this table. Something like that:
SELECT id
FROM news
WHERE cat_ids LIKE '%;15;%'
AND active = 1
AND publish_date < NOW()
ORDER by publish_date DESC
LIMIT 0, 10
But if my table is 2-3GB the query is very slow. I need some ideas to make structure and make the select faster.
Instead of using cat_ids column, try creating a news_cats table with news_id and cat_id, and using this query:
SELECT id
FROM news JOIN news_cats ON news_id = id
WHERE cat_id = 15
AND active = 1
AND publish_date < NOW()
ORDER by publish_date DESC
LIMIT 0, 10
Some suggestions as below:
1) Create index on "active" field
2) Create index on "publish_date" field
3) Create separate table for category and news relation and remove "cat_ids" field from news table
New table might look like below:
news_category_ids
news_id
category_id
It can have multiple rows for each news_id, if news item falls in 3 categories, it will have 3 rows
Then use SQL like below:
SELECT news.id
FROM news INNER JOIN news_category_ids ON news.id = news_category_ids.news_id
WHERE 1
AND news.active = 1
AND news_category_ids.cat_id = 15
AND news.publish_date < NOW()
ORDER by news.publish_date DESC
LIMIT 0, 10
How do I select a column value as a column name and group the results as a row.
I have a table as such:
id articleId label value
1 1 title Example title
2 1 description This is the description
3 1 author Me
4 2 title Example of another type of article
5 2 description Short description
6 2 author Someone else
Is it possible to select all of the rows and use the label as the column name and the value as the value of that column name and then group them by the article name.
So how I would like to have it returned:
articleId title description author
1 Example title This is the.. Me
2 Example of an.. Short descr.. Someone else
I'm using this for a CMS where the user can define the fields for an article so we don't have to customize the table's. This is why i'm not making the tables as the I would like to have it returned. I am also aware that I can just as easily convert the result to this in php.
-- edit --
Can this be done without knowing what labels are added? In this example im using title, description and author. But it could very well be something totally different like title, shortDescription, availableTo, techInformation, etc.. The idea is that the article's are customizable for the user without needing to change the database and query's
I figured I'd better post as an answer, even if not what OP would like to hear. What you are asking to do is to populate a query with a variable number of columns based on the distinct values within column label, all associated with articleID. Taking your specific example, the following would be the resultant query that I would most likely go to in this instance (though the example from #Devart is equally valid)
SELECT
t.id,
t.articleId,
t1.value AS title,
t2.value AS description,
t3.value AS author
FROM `tableName` t
LEFT JOIN `tablename` t1
ON t1.article_id = t.article_id AND t1.label = 'title'
LEFT JOIN `tablename` t2
ON t2.article_id = t.article_id AND t2.label = 'description'
LEFT JOIN `tablename` t3
ON t3.article_id = t.article_id AND t3.label = 'author'
Now expanding this to account for up to n labels, we get the following query (metacode included, this query will NOT execute verbatim)
SELECT DISTINCT label FROM `tableName`;
SELECT
t.id,
t.articleId
// for (i=1;i<= number of distinct labels) {
,t[i].value AS [value[i]]
// }
FROM `tableName` t
// for (i=1;i<= number of distinct labels) {
LEFT JOIN `tablename` t[i]
ON t[i].article_id = t.article_id AND t[i].label = [value[i]]
// }
;
So what you can do is one of the following.
SELECT t.* FROM tablename t and then have PHP process it as required
SELECT DISTINCT label FROM tablename and have PHP build the second query with the many LEFT JOINs (or MAX / GROUP BY logic if preferred)
Create a Stored Procedure to do the same as #2. This would most likely be more efficient than #2 however may be less efficient overall than #1.
You can use pivote table trick -
SELECT
articleId,
MAX(IF(label = 'title', value, NULL)) AS title,
MAX(IF(label = 'description', value, NULL)) AS description,
MAX(IF(label = 'author', value, NULL)) AS author
FROM
table
GROUP BY
articleId
Try below :
select t1.articleId,t1.title,t1.description,t1.author
from tablename as t1
left join (select max(articleId) as articleId
from tablename
group by articleId ) as t2
on t1.articleId=tsm.articleId where [.....]
I have a MYSQL5 database and PHP 5. I need a query for a games websites index page that only selects the first 12 from each category of games. Here is what I have so far.
$db->query("SELECT * FROM `games` WHERE status = 'game_published' AND `featured` = '1' ORDER BY `category`");
The php code then groups games of the same category together and displays them. But yeah it doesn't limit the number of games from each category like I want.
Here is exactly what the structure of the table looks like: i49.tinypic.com/aysoll.png
Here is a blog post which sounds like what I am trying to do: http://www.e-nformation.net/content/view/title/MySQL+Top+N+in+each+group+(group+inner+limit) But I can't make sense of it.
Any help is appreciated.
How about this?
SELECT * FROM (
SELECT
games.*,
#rn := CASE WHEN #category=category THEN #rn + 1 ELSE 1 END AS rn,
#category := category
FROM games, (SELECT #rn := 0, #category := NULL) AS vars
WHERE status = 'game_published' AND featured = '1'
ORDER BY category
) AS T1
WHERE rn <= 12
you could use UNION, if we are not talking about million of types...
pseudoSQL:
(SELECT * FROM table WHERE condition AND category = 'action' ORDER BY id LIMIT 10)
UNION
(SELECT * FROM table WHERE condition AND category = 'action' ORDER BY id LIMIT 10)
UNION
(SELECT * FROM table WHERE condition AND category = 'action' ORDER BY id LIMIT 10)
If you have array of categories in your PHP/ASP, you can generate this union on the fly.
More:
http://dev.mysql.com/doc/refman/5.0/en/union.html
EDIT:
Here's probably most useful resource: http://www.xaprb.com/blog/2006/12/07/how-to-select-the-firstleastmax-row-per-group-in-sql/
Use it well ^^
There may be a more elegant solution, but you can just execute a query for each category. First get a list of categories:
SELECT DISTINCT(category) FROM `games`;
Then take each of the results and query for 12 rows:
SELECT * FROM games WHERE status = 'game_published'
AND `featured` = '1' AND `category` = $category LIMIT 12;
Of course you need to add some kind of ranking row (and order by it) to get the top 12.
Note: There may be a way to do this with a single query, but it escapes me at the moment.
To use the technique from the posts you mention, you need a way to order the games. They're using article date. Then they select the number of older articles for that company, and say there can't be more than three.
If your games table has an auto-increment column called id, you can select the top 10 games per category like:
SELECT *
FROM games g1
WHERE status = 'game_published'
AND featured = '1'
AND 10 >
(
SELECT COUNT(*)
FROM games g2
WHERE g2.status = 'game_published'
AND g2.featured = '1'
AND g1.category = g2.category
AND g2.id > g1.id
)
The where condition says that there can't be more than 10 rows with the same category and a higher ID.