mysql summary query with special condition - mysql

I Have tables like below
How is query to show summary data like above?
NB: I was try, but my query result INDIA is 3. What i mean is only count company on period without count project with that period, so that the right result should is 2 like above
Thank You

You can try this
DEMO
Select countryname, count(distinct a.id_company) as sumval
from company a inner join project b on a.id_company=b.id_company
where b.period='2017'
group by countryname
OUTPUT:
countryname sumval
Franch 1
India 2

Related

get AVG() after GROUP BY in MYSQL

I just start to learn MYSQL and meet a problem like this
So the table is like this:
id name moneySpent
1 Alex 3
2 Alex 1
3 Bill 4
4 Alex 2
5 Alex 1
6 Chris 5
7 Chris 3
Lets say I wanna know the Average money spent per person. I try to do that by using SUM() GROUP BY and AVG() but I got stuck at AVG()
SELECT name, sum(moneySpent) AS total FROM table GROUP BY name;
then this will return
name total
Alex 7
Bill 4
Chris 8
Then how can I get a (7+4+8)/3 using AVG()?
You can get average per person using:
SELECT AVG(total) AS AVERAGE
FROM (SELECT name, sum(moneySpent) AS total
FROM table GROUP BY name) A
;
Output:
AVERAGE
6,3333
You can use inner query to get sum and outer query to derive average from sum as below.
SELECT Avg(sum1) FROM (
SELECT Sum(amount) AS sum1
FROM table1
GROUP BY NAME
) T1
It will generate below output.
AVERAGE_AMOUNT_SPENT
------------------
6.3333
which is what you want to be the output i.e. (7+4+8)/3 = 6.333
You can check demo here
So there are 2 ways to do this, first is use a new table to store the SELECT result. It is much more esay but may take more space.
Second is by jarlh, It comes to me that I do not need to GROUP BY the whole table, I can just add all moneySpent up and divided by distinct name count.
Thanks people!
select avg(total) as average from (SELECT name, sum(moneySpent) AS total FROM table GROUP BY name);
You can use this query to get your desired output
OUTPUT:
AVERAGE
6.3333333333333333

How to Count Distinct with Group By and the entire Column

I'm having a hard time wording what I need/wording the search result, so apologies if this is a stupid question/has been answered before. I'm trying to write a query in SQL for a table such as below:
Country Unique_ID
US 123
US 124
UK 125
Australia 126
That will output the follow table:
Country Count_Distinct
US 2
UK 1
Australia 1
All 4
I know I can select the countryid and count distinct the country codes, and I know I can just count distinct the countryid codes to get the "All" number. I can't figure out how to write a query to get the follow output that's not two separate queries.
If you need information or clarification please let me know. Thanks!
Use WITH ROLLUP:
select Country, count(distinct Unique_ID) Count_Distinct
from mytable
group by Country
with rollup
If you want the text "All" (you get a null for the country by default), wrap it in another query to change the null to "All":
select coalesce(Country, "All") Country, Count_Distinct
from (
select Country, count(distinct Unique_ID) Count_Distinct
from mytable
group by Country
with rollup
) x
Can you please try this :
select country,count(distinct unique_id) as count distinct
from table
group by rollup(country)

SQL sum and count command. How do I group my table content to output two groups (rows) of results?

This is my SQL table:
So this is my sql query:
SELECT sponsor_name, sub_name, sum(amount), count(id)
FROM sponsor
and the output is like this:
I want the output to show both Adidas and Dell Computers with their own sum and count. So it will show two rows like:
sponsor_name
sub_name
sum(amount)
count(id)
Adidas
Food Bank Kelowna
9000
4
Dell Computer
Food Bank Kelowna
1500
3
You should group by the columns you don't want to aggregate. In this case, sponsor_name and sub_name:
SELECT sponsor_name, sub_name, SUM(amount), COUNT(id)
FROM sponsor
GROUP BY sponsor_name, sub_name
COUNT and SUM (among others) are Aggregated Functions, that means they return a single value grouped somehow (by a column or a set of columns). You should do this by specifying a GROUP BY clause in your query.
So, try this:
SELECT sponsor_name, sub_name, sum(amount), count(1)
FROM SPONSOR
GROUP BY sponsor_name, sub_name;

How can I write a query that aggregate a single row with latest date among multiple set of rows?

I have a MySQL table where there are many rows for each person, and I want to write a query which aggregates rows with special constraint. (one per person)
For example, lets say the table is consist of following data.
name date reason
---------------------------------------
John 2013-04-01 14:00:00 Vacation
John 2013-03-31 18:00:00 Sick
Ted 2012-05-06 20:00:00 Sick
Ted 2012-02-20 01:00:00 Vacation
John 2011-12-21 00:00:00 Sick
Bob 2011-04-02 20:00:00 Sick
I want to see the distribution of 'reason' column. If I just write a query like below
select reason, count(*) as count from table group by reason
then I will be able to see number of reasons for this table overall.
reason count
------------------
Sick 4
Vacation 2
However, I am only interested in single reason from each person. The reason that should be counted should be from a row with latest date from the person's records. For example, John's latest reason would be Vacation while Ted's latest reason would be Sick. And Bob's latest reason (and the only reason) is Sick.
The expected result for that query should be like below. (Sum of count will be 3 because there are only 3 people)
reason count
-----------------
Sick 2
Vacation 1
Is it possible to write a query such that single latest reason will be counted when I want to see distribution(count) of reasons?
Here are some facts about the table.
The table has tens of millions of rows
For most of times, each person has one reason.
Some people have multiple reasons, but 99.99% of people have fewer than 5 reasons.
There are about 30 different reasons while there are millions of distinct names.
The table is partitioned based on date range.
SELECT T.REASON, COUNT(*)
FROM
(
SELECT PERSON, MAX(DATE) AS MAX_DATE
FROM TABLE-NAME
GROUP BY PERSON
) A, TABLE-NAME T
WHERE T.PERSON = A.PERSON AND T.DATE = A.MAX_DATE
GROUP BY T.REASON
Try this
select reason, count(*) from
(select reason from table where date in
(select max(date) from table group by name)) t
group by reason
In MySQL, it's not very efficient to do this kind of query since you don't have access to tools like partitionning query in SQL Server or Oracle.
You can still emulate it by doing a subquery and retrieve the rows based on the condition you need, here the maximum date :
SELECT t.reason, COUNT(1)
FROM
(
SELECT name, MAX(adate) AS maxDate
FROM #aTable
GROUP BY name
) maxDateRows
INNER JOIN #aTable t ON maxDateRows.name = t.name
AND maxDateRows.maxDate = t.adate
GROUP BY t.reason
You can see a sample here.
Test this query on your samples, but I'm afraid that it will be slow as hell.
For your information, you can do the same thing in a more elegant and much much faster way in SQL Server :
SELECT reason, COUNT(1)
FROM
(
SELECT name
, reason
, RANK() OVER(PARTITION BY name ORDER BY adate DESC) as Rank
FROM #aTable
) AS rankTable
WHERE Rank = 1
GROUP BY reason
The sample is here
If you are really stuck to MySql, and the first query is too slow, then you can split the problem.
Do a first query creating a table:
CREATE TABLE maxDateRows AS
SELECT name, MAX(adate) AS maxDate
FROM #aTable
GROUP BY name
Then create index on both name and maxDate.
Finally, get the results :
SELECT t.reason, COUNT(1)
FROM maxDateRows m
INNER JOIN #aTable t ON m.name = t.name
AND m.maxDate = t.adate
GROUP BY t.reason
The solution you are looking for seems to be solved by this query :
select
reason,
count(*)
from (select * from tablename group by name) abc
group by
reason
It is quite fast and simple. You can view the SQL Fiddle
Apologies if this answer duplicates an existing. Maybe I'm suffering from some form aphasia but I cannot see it...
SELECT x.reason
, COUNT(*)
FROM absentism x
JOIN
( SELECT name,MAX(date) max_date FROM absentism GROUP BY name) y
ON y.name = x.name
AND y.max_date = x.date
GROUP
BY reason;

Select distinct column along with some other columns in MySQL

I can't seem to find a suitable solution for the following (probably an age old) problem so hoping someone can shed some light. I need to return 1 distinct column along with other non distinct columns in mySQL.
I have the following table in mySQL:
id name destination rating country
----------------------------------------------------
1 James Barbados 5 WI
2 Andrew Antigua 6 WI
3 James Barbados 3 WI
4 Declan Trinidad 2 WI
5 Steve Barbados 4 WI
6 Declan Trinidad 3 WI
I would like SQL statement to return the DISTINCT name along with the destination, rating based on country.
id name destination rating country
----------------------------------------------------
1 James Barbados 5 WI
2 Andrew Antigua 6 WI
4 Declan Trinidad 2 WI
5 Steve Barbados 4 WI
As you can see, James and Declan have different ratings, but the same name, so they are returned only once.
The following query returns all rows because the ratings are different. Is there anyway I can return the above result set?
SELECT (distinct name), destination, rating
FROM table
WHERE country = 'WI'
ORDER BY id
Using a subquery, you can get the highest id for each name, then select the rest of the rows based on that:
SELECT * FROM table
WHERE id IN (
SELECT MAX(id) FROM table GROUP BY name
)
If you'd prefer, use MIN(id) to get the first record for each name instead of the last.
It can also be done with an INNER JOIN against the subquery. For this purpose the performance should be similar, and sometimes you need to join on two columns from the subquery.
SELECT
table.*
FROM
table
INNER JOIN (
SELECT MAX(id) AS id FROM table GROUP BY name
) maxid ON table.id = maxid.id
The problem is that distinct works across the entire return set and not just the first field. Otherwise MySQL wouldn't know what record to return. So, you want to have some sort of group function on rating, whether MAX, MIN, GROUP_CONCAT, AVG, or several other functions.
Michael has already posted a good answer, so I'm not going to re-write the query.
I agree with #rcdmk . Using a DEPENDENT subquery can kill performance, GROUP BY seems more suitable provided that you have already INDEXed the country field and only a few rows will reach the server. Rewriting the query giben by #rcdmk , I added the ORDER BY NULL clause to suppress the implicit ordering by GROUP BY, to make it a little faster:
SELECT MIN(id) as id, name, destination as rating, country
FROM table WHERE country = 'WI'
GROUP BY name, destination ORDER BY NULL
You can do a GROUP BY clause:
SELECT MIN(id) AS id, name, destination, AVG(rating) AS rating, country
FROM TABLE_NAME
GROUP BY name, destination, country
This query would perform better in large datasets than the subquery alternatives and it can be easier to read as well.