i am a newbie to SQL.
I wanna find out what which player is oldest by age.
So here is my table..
Somehow my Query give error.
Can you please tell me where i am doing it wrong.
Thanks.
select * from players
where age = (select max(age) as Oldest_Player from players);
limit 1
SQL has a SELECT TOP command, which allows you to retrieve a set number of rows. You can do SELECT TOP 1 name AS 'Oldest Person' FROM players ORDER BY age DESC
What this will do is: first retrieve all the players, sort them by age descending (oldest first), then take the first one.
You can use row_number as below:
Select * from (
Select *, RowN = Row_Number() over(order by age desc) from Players
) a Where a.RowN = 1
Related
SELECT MAX(Score)
FROM Students
WHERE Score < (SELECT MAX(Score) FROM Students);
the above query works perfectly and fetches the record that has 2nd highest score, whereas the query mentioned below does not fetch anything
SELECT *
FROM Students
WHERE Score < (SELECT MAX(Score) FROM Students);
here Students is the table from which I want to fetch all the details of that record which has 2nd highest score in the entire table.
I want that 2nd query should get executed, thanks in advance for helping me out.
I have not used any database, I'm simply trying out these queries in w3schools.
With standard SQL, this is typically solved using window functions:
select *
from (
select *, dense_rank() over (order by score desc) as rnk
from students
) t
where rnk = 2;
The above is ANSI standard SQL and works on all modern DBMS.
How about ordering and getting the first record returned using LIMIT:
SELECT *
FROM Students
WHERE Score < (SELECT MAX(Score) FROM Students)
ORDER BY Score DESC
LIMIT 1;
I am trying to generate a TSQL query that will take the top 3 scores (out of about 50) for a group of teams, sum the total of just those 3 scores and give me a result set that has just the name of the team, and that total score ordered by the score descending. I'm pretty sure it is a nested query - but for the life of me can't get it to work!
Here are the specifics, there is only 1 table involved....
table = comp_lineup (this table holds a separate record for each athlete in a match)
* athlete
* team
* score
There are many athletes to a match - each one belongs to a team.
Example:
id athlete team score<br>
1 1 1 24<br>
2 2 1 23<br>
3 3 2 21<br>
4 4 2 25<br>
5 5 1 20<br>
Thank You!
It is indeed a subquery, which I often put in a CTE instead just for clarity. The trick is the use of the rank() function.
;with RankedScores as (
select
id,
athlete,
team,
score,
rank() over (partition by team order by score desc) ScoreRank
from
#scores
)
select
Team,
sum(Score) TotalScore
from
RankedScores
where
ScoreRank <= 3
group by
team
order by
TotalScore desc
To get the top n value for every group of data a query template is
Select group_value, sum(value) total_value
From mytable ext
Where id in (Select top *n* id
From mytable sub
Where ext.group_value = sub.group_value
Order By value desc)
Group By group_value
The subquery retrieve only the ID of the valid data for the current group_value, the connection between the two dataset is the Where ext.group_value = sub.group_value part, the WHERE in the main query is used to mask every other ID, like a cursor.
For the specific question the template became
Select team, sum(score) total_score
From mytable ext
Where id in (Select top 3 id
From mytable sub
Where ext.team = sub.team
Order By score desc)
Group By team
Order By sum(score) Desc
with the added Order By in the main query for the descending total score
Let's say I have a bases with a table:
-courses (key: name [ofthecourse], other attributes: year in which the course takes place)
I want to complete a query looking for an answer to the question:
On which year of study there is a maximum number of courses?
Normally, the query would be:
SELECT TOP 1 STUDYEAR
FROM COURSES
GROUP BY STUDYEAR
ORDER BY COUNT(CNO) DESC;
But my question is, which query could complete this without using the TOP 1 phrase?
You can use an inner query to get the maximum count. The only difference is though that it can return more than one record if they have the same count.
SELECT STUDYEAR
FROM COURSES
GROUP BY STUDYEAR
HAVING COUNT(CNO) = (SELECT MAX(CNOCount) FROM
(SELECT COUNT(CNO) CNOCount
FROM COURSES
GROUP BY STUDYEAR) X)
Another version with only one inner query:
SELECT STUDYEAR
FROM
(SELECT STUDYEAR, ROW_NUMBER() OVER (ORDER BY COUNT(CNO) DESC) RowNumber
FROM COURSES
GROUP BY STUDYEAR) X
WHERE RowNumber = 1
Note: this is in Oracle not MySQL, limit/top won't work.
I want to return the name of the person that has stayed the longest in a hotel. The longest stay can be found by subtracting the date in the checkout column with the checkin column.
So far I have:
select fans.name
from fans
where fans.checkout-fans.checkin is not null
order by fans.checkout-fans.checkin desc;
but this only orders the length of stay of each person from highest to lowest. I want it to only return the name (or names, if they are tied) of people who have stayed the longest. Also, As more than one person could have stayed for the highest length of time, simply adding limit 1 to the end won't do.
Edit (for gbn), when adding a join to get checkin/checkout from other table it wont work (no records returned)
edit 2 solved now, the below join should of been players.team = teams.name
select
x.name
from
(
select
players.name,
dense_rank() over (order by teams.checkout-teams.checkin desc) as rnk
from
players
join teams
on players.name = teams.name
where
teams.checkout-teams.checkin is not null
) x
where
x.rnk = 1
Should be this using DENSE_RANK to get ties
select
x.name
from
(
select
fans.name,
dense_rank() over (order by fans.checkout-fans.checkin desc) as rnk
from
fans
where
fans.checkout-fans.checkin is not null
) x
where
x.rnk = 1;
SQL Server has TOP..WITH TIES for this, but this is a generic solution for any RDBMS that has DENSE_RANK.
Longest is a fuzzy word, you should first define what is long for you. Using limit may not be a solution for this case. So you can define your treshold and try to filter your results where fans.checkout-fans.checkin > 10 for instance.
Try this:
select name, (checkout-checkin) AS stay
from fans
where stay is not null -- remove fans that never stayed at a hotel
order by stay desc;
For Oracle:
select * from
(
select fans.name
from fans
where fans.checkout-fans.checkin is not null
order by fans.checkout-fans.checkin desc)
where rownum=1
Another way that should work in all dbms (or almost all, at least those that support subqueries):
select fans.name
from fans
where fans.checkout-fans.checkin =
( select max(f.checkout-f.checkin)
from fans f
) ;
If both the columns are date fields you can use this query:
select fans.name from fans where fans.checkout-fans.checkin in (select max(fans.checkout-fans.checkin) from fans );
Ive got table with columns:
PlayerId
Points
I would like to get 100 best players (the more points player have, the better he is). What would be the quesry for that ?
Im using sql server 2008
SELECT TOP 100 PlayerId
FROM TableName
ORDER BY Points DESC
To break it down:
TOP 100 - Selects the top 100 records to return.
ORDER BY Points DESC - Orders the results by the Points field, and DESC sets them in numerical reverse (assuming Points is an integer data type).
You'll need to select the top X from the query and then order by the points in descending order.
select top 100 * from players order by Points DESC
What happens when two or more players have the same points?, or even worse, what happens if you have 120 players with the maximum points. You should use a query that returns every one of those players. I recommend that you use RANK if this is the case.
;WITH CTE AS
(
SELECT *, RANK() OVER(ORDER BY Points DESC) RN
FROM Players
)
SELECT *
FROM CTE
WHERE RN <= 100
SELECT TOP 100 PlayerID
FROM <<Table>>
ORDER BY Points DESC
Assuming your table name is Players:
SELECT TOP 100 PlayerId, Points
FROM Players
ORDER BY Points DESC
SELECT TOP 100 *
FROM tblName ORDER BY Points DESC
SELECT TOP 100 PlayerId FROM name_of_your_table ORDER BY Points DESC