my table:
id | item_id
1 | 5
2 | 5
3 | 7
4 | 2
sql:
$countWeek = $conn->query("SELECT count(item_id) FROM `myTable` GROUP BY `item_id`")->fetchColumn();
As you can see i have 2 duplicated rows with item_id = 5 i want to group these duplicated rows and output 3 rows on the count, but when i do echo $countWeek it output 1, why?
When i change the above sql to:
$countWeek = $conn->query("SELECT item_id FROM `myTable` GROUP BY `item_id`")->rowCount();
It returns the correct value, but i don't want to use rowCount() because i only need to count the rows and fetchColumn() with count() is far better in terms of speed.
You could use counct(distinct item_id)
SELECT count(distinct item_id)
FROM `myTable`
Related
I have 2 tables : priority_list and priority_list_delete
I want to get the following data in a single row:
1) Sum of these 2 table records
2) Count of individual table records
3) Count of priority_list_delete table records category wise
This is what I have done so far:
SELECT
(SELECT COUNT(*) FROM priority_list)+(SELECT COUNT(*) from
priority_list_delete) as tot_count,
(SELECT COUNT(*) FROM priority_list) as prior_cnt,
(SELECT COUNT(*) FROM priority_list_delete) as prior_del_cnt
The above query returns the count of the tables but when I merge the below query with the above one, it throws an error:
(SELECT category, COUNT(*) FROM priority_list_delete group by category)
I guess, there is some syntax error which I am unable to sort it out and moreover I am not getting idea about how to get the count records category wise where category names will be the column name.
Example format:
tot_count| prior_cnt| prior_del_cnt| ST | OBC
---------|----------|--------------|------|------
920 | 893 | 27 | 64 | 100
Here ST and OBC are the categories.
Any help would be appreciated.
Thanks in advance.
I think your exact desired output might be tough to do, because the number of category columns is dynamic. But we can try reporting categories across rows:
SELECT category, cnt
FROM
(
SELECT category, COUNT(*) AS cnt, 0 AS pos
FROM priority_list_delete
GROUP BY category
UNION ALL
SELECT 'prior_cnt', COUNT(*), 1 FROM priority_list
UNION ALL
SELECT 'prior_del_cnt', COUNT(*), 2 FROM priority_list_delete
UNION ALL
SELECT 'tot_count', (SELECT COUNT(*) FROM priority_list) +
(SELECT COUNT(*) FROM priority_list_delete), 3
) t
ORDER BY pos, category;
This would give an output looking something like:
category | cnt
ST | 64
OBC | 100
prior_cnt | 893
prior_del_cnt | 27
tot_count | 920
So I have a student_profiles table and ranks table, I want to get the next rank based on the student rank. For example, I have rank 5 then the next rank will be rank 6. So this is my rank structure.
RANKS TABLE:
SELECT * FROM RANKS WHERE style_id = 1"
id style_id level name type primary_colour secondary_colour
1 1 1 Newbie double #4e90b2 #3aad04
22 1 2 Normal solid #fba729 NULL
31 1 3 Expert solid #4e805b NULL
and this is STUDENT_PROFILES TABLE
id | student_id | rank_id
------------------------------------
1 | 1 | 36
2 | 4 | 22
3 | 7 | 10
so all I have a variable is student_id, rank_id & style_id
so for example, I have this value student_id = 4, rank_id = 22 & style_id = 1
It should return
id style_id level name type primary_colour secondary_colour
31 | 1 | 3 | Expert | Solid | #4e805b | NULL
If you just want to get the second row:
Do it like this:
select * from
(select * from table order by id asc limit 2) as a order by id desc limit 1
Any query structure it will work as you need second row if you follow that script.
Try with that:
SELECT * FROM `ranks` WHERE `level` > (SELECT `level` FROM `ranks` WHERE `id` = rank_id) LIMIT 1
But I think it isn't very effective solution.
One option for getting the next highest level in the RANKS table is to self-join this table on the level column, order ascending, and retain the very first record only.
SELECT r2.*
FROM RANKS r1
INNER JOIN
STUDENT_PROFILES s1
ON r1.id = s1.rank_id
INNER JOIN
RANKS r2
ON r2.level > r1.level
ORDER BY r2.level
LIMIT 1
Demo here:
SQLFiddle
Note: If RANKS has duplicate levels, and you want the next level with regard to cardinality (i.e. you don't want a duplicate equal level returned), then my query could be slightly modified to filter out such duplicates.
i have a table like this on a mysql database:
id | item
-----------
1 | 2
2 | 2
3 | 4
4 | 5
5 | 8
6 | 8
7 | 8
i want the result to be 3 record with the highest Item value
select max(item) returns only 1 value
how can i select multiple max values?
thank you
You can use a derived table to get the maximum value and join it back to the original table to see all rows corresponding to it.
select t.id, t.item
from tablename t
join (select max(item) as mxitem from tablename) x
on x.mxitem = t.item
Edit:
select t.co_travelers_id, t.booking_id, t.accounts_id
from a_co_travelers t
join (select accounts_id, max(booking_id) as mxitem
from a_co_travelers
group by accounts_id) x
on x.mxitem = t.booking_id and t.accounts_id = x.accounts_id
If you use an 'aggregate function' without GROUP BY only one row will be returned.
You may use GROUP BY , with aggregate functions.
Here is SQLFiddle Demo
SELECT id,max(item) AS item
FROM table_name
GROUP BY id
ORDER BY item DESC
LIMIT 3
Hope this helps.
There is the graphical explanation.
There is script mysql (low abstraction level, no inner join or sth)
select * from ocena, uczen where ocena.ocena = (SELECT MAX(ocena.ocena) FROM ocena WHERE ocena.przedmiot_id="4" and ocena.uczen_id="1") and ocena.uczen_id=uczen.id and ocena.przedmiot_id="4" and uczen_id="1"
date | userid | companyid
12.8.14 | 1 | 1
12.8.14 | 2 | 2
12.8.14 | 3 | 1
I had a table like above. It is easy to count how many company 1 from table with normal query.
My question is : if my query is select * from table where companyid = '1' group by date, how can i get mysql_num_row equal to 2 for company 1 and userid is 1 and 3?
select * from table where companyid = '1' group by date will only return me
mysql_num_row equal 1 and result 12.8.14 | 1 | 1
You can nest a query to get the sum of company one entries and then join that nested query to an outer query:
SELECT ABB2.*, ABB1.mysql_num_row
FROM `table` AS ABB2
JOIN
(SELECT companyid, COUNT(userid) AS mysql_num_row
FROM `table`
GROUP BY companyid) AS ABB1 ON ABB1.companyid = ABB2.companyid
WHERE ABB2.companyid = 1;
Example
try like this also
select *,(select count(*) from table1 where companyid=a.companyid) as count
from t as a where companyid=1
You wanted:
select date,companyid,count(*)
from table
where userid = 1
group by date,companyid
Extending further from this question Query to find top rated article in each category -
Consider the same table -
id | category_id | rating
---+-------------+-------
1 | 1 | 10
2 | 1 | 8
3 | 2 | 7
4 | 3 | 5
5 | 3 | 2
6 | 3 | 6
There is a table articles, with fields id, rating (an integer from 1-10), and category_id (an integer representing to which category it belongs). And if I have the same goal to get the top rated articles in each query (this should be the result):-
Desired Result
id | category_id | rating
---+-------------+-------
1 | 1 | 10
3 | 2 | 7
6 | 3 | 6
Extension of original question
But, running the following query -
SELECT id, category_id, max( rating ) AS max_rating
FROM `articles`
GROUP BY category_id
results into the following where everything, except the id field, is as desired. I know how to do this with a subquery - as answered in the same question - Using subquery.
id category_id max_rating
1 1 10
3 2 7
4 3 6
In generic terms
Excluding the grouped column (category_id) and the evaluated columns (columns returning results of aggregate function like SUM(), MAX() etc. - in this case max_rating), the values returned in the other fields are simply the first row under every grouped result set (grouped by category_id in this case). E.g. the record with id =1 is the first one in the table under category_id 1 (id 1 and 2 under category_id 1) so it is returned.
I am just wondering is it not possible to somehow overcome this default behavior to return rows based on conditions? If mysql can perform calculation for every grouped result set (does MAX() counting etc) then why can't it return the row corresponding to the maximum rating. Is it not possible to do this in a single query without a subquery? This looks to me like a frequent requirement.
Update
I could not figure out what I want from Naktibalda's solution too. And just to mention again, I know how to do this using a subquery, as again answered by OMG Ponies.
Use:
SELECT x.id,
x.category_id,
x.rating
FROM YOUR_TABLE x
JOIN (SELECT t.category_id,
MAX(t.rating) AS max_rating
FROM YOUR_TABLE t
GROUP BY t.category_id) y ON y.category_id = x.category_id
AND y.max_rating = x.rating