I'm trying to change two SQL queries I have right now so that in addition to giving me a result from a table, it only gives me that result based on the newest say 150 entries within the table.
My two queries at the moment are:
SELECT COUNT(*)
FROM `stock`.`replacements.archive`
WHERE `ciref` = '$cihistory'
and
SELECT `req_model`, COUNT(`req_model`) AS `value_occurrence`
FROM `stock`.`replacements.archive`
GROUP BY `req_model`
ORDER BY `value_occurrence` DESC LIMIT 5
Is there a way for me to achieve this?
The id field in the table is used as normal so guessing would use this but im not sure how to achieve it
The aim here is to only do the counting of the variable based on the latest 150 entries in the table, i dont want to count everything in the table.
Anyone has any ideas it would be much appreciated!
Thanks
assuming you have an autoincremnt id the you could select the newest 150 entry as
SELECT *
FROM `stock`.`replacements.archive`
ORDER BY id limit 150
and then perform the query on this subquery as
SELECT `req_model`, COUNT(`req_model`) AS `value_occurrence`
FROM (
SELECT *
FROM `stock`.`replacements.archive`
ORDER BY id DESC limit 150
) t
GROUP BY `req_model`
ORDER BY `value_occurrence`
Related
I'm working on php small project, here I need first 5 records from beginning of records and last record 1 from end of the table's record. I don't know how to write a single mysqli query.
Any help will be appreciated. Thanks in advance.
SQL tables represent unordered sets. So, there is no such thing as the first five rows or last row -- unless a column explicitly defines the ordering.
Often, a table has some sort of auto-incremented id column, which can be used for this purpose. If so, you can do:
(select t.*
from t
order by id asc
limit 5
) union all
(select t.*
from t
order by id desc
limit 1
);
Notes:
Sometimes, an insert date/time column is the appropriate column to use.
You want to use union all rather than union -- unless you want to incur the overhead of removing duplicate values.
For this formulation, if there are fewer than 6 rows, then you will get a duplicate.
The UNION operator allows this, carefully toying with the ORDER BY and LIMIT clauses :
(SELECT * FROM table ORDER BY field ASC LIMIT 5)
UNION
(SELECT * FROM table ORDER BY field DESC LIMIT 1)
I have a table in my database which is updated randomly. I'm trying to pull entries by the latest date. This part is simply and I can do it with ease. However, I want to pull the two latest dates.
Example; If my last update was 2015-06-22 and the one before than was 2015-06-12 and the one before then was 2015-06-02. I would want to pull 2015-06-22 and 2015-06-15.
I would use a LIMIT 2, however, there are an unknown amount of items that may have the same date attached.
I haven't tried anything other than the LIMIT 2. After some research, I wasn't able to find anything to reference.
Update
I used SELECT DISTINCT to get the desired results.
SELECT DISTINCT dates FROM table ORDER BY dates DESC LIMIT 2
Will give you the latest 2 dates in the table.
I would have a column set to id, that is auto incremented, and do my query like this:
SELECT * FROM tbl_name ORDER BY `id` DESC LIMIT 2
Crap McAdam you beat me to it!
You can get the latest two dates using LIMIT, like you mentioned:
SELECT latestDates
FROM myTable
ORDER BY dateColumn DESC
LIMIT 2;
And you can join that to your original table to only select rows that occur on those two dates:
SELECT m.*
FROM myTable m
JOIN(
SELECT latestDates
FROM myTable
ORDER BY dateColumn DESC
LIMIT 2) tmp ON tmp.latestDates = m.dateColumn;
i have 2 tables:
1st table is called maxlift with 1 column called, exercise
2nd table is called workout with 5 columns called, exercise, sets, reps, weight, date
i want display the highest weight for each exercise where exercise in both tables is the same.
i am using:
`SELECT *
FROM workout, maxlift
WHERE workout.exercise = maxlift.exercise
GROUP BY maxlift.exercise
ORDER BY workout.weight desc`
the problem i have is the weight displayed is not the highest weight from table workout.
thanks for any help.
You can use the aggregate function max() for this.
SELECT workout.exercise, max(weight) as weight
FROM workout, maxlift
WHERE workout.exercise=maxlift.exercise
GROUP BY workout.exercise;
Now, you basically group by exercise and find the maximum weight for each such group using the max() function. You can alias your selected column using column_name as alias.
`SELECT *
FROM workout, maxlift
WHERE workout.exercise = maxlift.exercise
ORDER BY workout.weight desc`
use this by removing group by and let me know about it
I've got following tables in my MySQL database:
USERS
iduser nick password
ARTICLES
idarticles iduser text
How can I get by one SQL query the list of e.g. 10 top publishers of articles ordering by the count of added articles? Is there any way to do that? I'm using PHP to ask database.
Yes, this should be quite easy via JOIN and COUNT(). Something like the following
SELECT `users`.`iduser`, COUNT(`articles`.`idarticles`) AS `total_articles`
FROM `users`
INNER JOIN `articles` ON `users`.`iduser` = `articles`.`iduser`
GROUP BY `users`.`iduser`
ORDER BY `total_articles` DESC
LIMIT 10
A little explaining:
COUNT() will get you what it says - a count of all relevant entries in articles
INNER JOIN will pair all entries that belong together (defined via ON)
GROUP BY tells SQL that you are interested in various results, each differing by iduser (without this, you'd get all articles counted in the first returned row)
ORDER BY .. DESC is important to get the result in a descending order (so most published first)
LIMIT 10 does exactly that
I want to create a random image banner which fetches the image data from a MySQL database.
And I only want to fetch the latest three records, randomly.
How can I fetch the the 3 most recent records, in a random order?
I am the following query:
SELECT * FROM bottom_advt WHERE bottom_advt_page_name='News' ORDER BY RAND() LIMIT 1
but it's not working.
You said 3 records. So try:
SELECT * FROM bottom_advt WHERE bottom_advt_page_name='News' ORDER BY RAND() LIMIT 3
You're limiting your results to one with LIMIT 1. Change it to LIMIT 3 to get three results.
Try this if you want one of the last three records:
SELECT * FROM bottom_advt WHERE bottom_advt_page_name='News' AND id+3>last_insert_id() ORDER BY RAND() LIMIT 1
You could use this:
SELECT *
FROM bottom_advt
WHERE ID IN (SELECT * FROM (
SELECT id
FROM bottom_advt
WHERE bottom_advt_page_name='News'
ORDER BY id DESC
LIMIT 3) last)
ORDER BY RAND()
LIMIT 1
Subquery will return the last 3 id that have bottom_advt_page_name='News', and the outer query will randomly select one of those.
Please see fiddle here.