I have one file (name File1) who is like that:
AGE NAME (names are unique)
10 john
20 fred
10 james
15 jack
20 alfred
20 henry
and I would like to get the name of the olders with one query:
AGE NAME
20 fred
20 alfred
20 henry
Is it possible?
SQL:
SELECT AGE, NAME FROM File1 WHERE AGE = (SELECT MAX(AGE) FROM File1)
Related
i have a table like this:
id
person
20
adams
20
george
40
jina
46
rico
80
naya
90
john
90
peter
90
richard
i want to find a way to select a new_id starting from 1 and increazing +1 every time id is different. for example i want a select with a result like this:
new_id
id
person
1
20
adams
1
20
george
2
40
jina
3
46
rico
4
80
naya
5
90
john
5
90
peter
5
90
richard
is there any function in postgres doing something like that?
use dense_rank()
select dense_rank()over(order by id) as newid,id,persion
from table_name
demo link
I'm fairly new to SQL but having searched the internet for an answer to this I still cannot get my COUNT and EXCEPT statements to select what I want.
My Database:
sqlite> CREATE TABLE Football(Team TEXT, Player TEXT, Age INTEGER, primary key(Team, Player));
sqlite> .separator ,
sqlite> .import databaseTest Football
sqlite> .headers on
sqlite> .mode col
sqlite> SELECT Team, Player, Age FROM Football ORDER BY Team;
Team Player Age
---------- ---------- ----------
Arsenal Cech 38
Arsenal Giroud 29
Arsenal Sanchez 28
Arsenal Walcott 27
Chelsea Costa 29
Chelsea Courtois 25
Chelsea Hazard 26
Chelsea Willian 26
Liverpool Can 23
Liverpool Coutinho 24
Liverpool Wjinaldum 25
Liverpool Woodburn 17
Manchester Aguero 29
Manchester Jesus 19
Manchester Silva 28
Manchester Toure 34
Manchester De Gea 26
Manchester Felliani 29
Manchester Rooney 32
Manchester Schweinste 35
Tottenham Delle Ali 22
Tottenham Kane 24
Tottenham Rose 24
Tottenham Vertonghen 27
What I want to do is SELECT the COUNT of teams that do not have a player over the age of 30. So the select statement should be 3 (Chelsea, Liverpool, Tottenham).
This is the statement I've tried and assumed would work:
sqlite> SELECT COUNT(DISTINCT Team) FROM Football
...> EXCEPT
...> SELECT COUNT(DISTINCT Team) FROM Football WHERE Age > 30;
COUNT(DISTINCT Team)
--------------------
6
But as you can see it returns '6'. What am I doing wrong and how can I get the correct result?
Here is another way. Look at the maximum age for each team:
SELECT COUNT(*)
FROM (SELECT Team
FROM Football
GROUP BY Team
HAVING MAX(Age) <= 30
) t;
You can also use EXCEPT, but this also requires a subquery. You need to do the set operation before doing the count:
SELECT COUNT(DISTINCT TEAM)
FROM (SELECT Team FROM Football
EXCEPT
SELECT Team FROM Football WHERE Age > 30
) t;
Strictly speaking, this query could use COUNT(*) rather than COUNT(DISTINCT). However, it can be troublesome to remember that EXCEPT (like UNION) removes duplicate values.
The query I'm trying to answer is 'How many sales above or equal to 60 has each person made?'
My table (sales$):
SaleID name salevalue
1 Steve 100
2 John 50
3 Ellen 25
4 Steve 100
5 Mary 60
6 Mary 80
7 John 70
8 Mary 55
9 Steve 65
10 Ellen 120
11 Ellen 30
12 Ellen 40
13 John 40
14 Mary 60
15 Steve 50
My code is:
select name,
COUNT(*) as 'sales above 60'
from Sales$
group by salevalue, name
having salevalue >= 60;
Which gives:
Ellen 1
John 1
Mary 2
Mary 1
Steve 1
Steve 2
The information is correct in that Mary & Steve both have 3 sales, however I'm forced by the HAVING command to group them out.
Any ideas? I'm sure I've just taken a wrong turning.
You can use conditional aggregation for this:
select name,
COUNT(case when salevalue >= 60 then 1 end) as 'sales above 60'
from Sales$
group by name
This way COUNT will take into consideration only records having salevalue >= 60.
I've swapped the HAVING statement for a WHERE and achieved the desired result:
select name, count(*) 'sales above 50'
from sales$
where salevalue >=60
group by name
(Lightbulb moment after posting)
Let's say there's a table called Winner, with 3 attributes: Name, Gender and Id.
Name Gender Id
Kevin Male 8
Kevin Male 8
Benny Male 31
Jenny Female 7
Louie Male 4
Peter Male 11
Kevin Male 2
Jenny Female 7
Jenny Female 7
Chris Male 23
Louie Female 14
Apart from those people who is actually 2 different person but with the same name and those people who have the same name but with different gender, their Id's will be the unique value to identify themselves. If I want to list all the Id's who appeared once only in the list, I am thinking to do something like this:
Am I expressing it correctly ?
I don't know what your formula is trying to say, but in SQL you can achieve the result you want with a GROUP BY query:
SELECT Id, COUNT(Id) AS idCount
FROM Winner
GROUP BY Id
HAVING COUNT(Id) = 1
Suppose I have:
A B
andy 10
andy 20
andy 30
andy 40
paul 10
paul 50
ryan 3
... and I want the result to be:
A B C
andy 10 10
andy 20 30
andy 30 60
andy 40 100
paul 10 10
paul 50 60
ryan 3 3
What query will achieve this for me? Think of C as a cumulative frequency.
One way to do it.. untested suggestion... a sub-select totals up the relevant values where they match and are in order before the current line...
SELECT
name as A,
value as B,
( SELECT sum(value) FROM the_table t2 WHERE t2.name=t1.name
AND t2.second_order_field<=t1.second_order_field ) as C
FROM the_table t1
ORDER BY t1.name,t1.second_order_field