So I have this query:
SELECT
Search.USER_ID,
Search.SEARCH_TERM,
COUNT(*) AS Search.count
FROM Search
GROUP BY 1,2
ORDER BY 3 DESC
Which returns a response that looks like this:
USER_ID SEARCH_TERM count
bob dog 50
bob cat 45
sally cat 38
john mouse 30
sally turtle 10
sally lion 5
john zebra 3
john leopard 1
And my question is: How would I change the query, so that it only returns the top 2 most-searched-for-terms for any given user? So in the example above, the last row for Sally would be dropped, and the last row for John would also be dropped, leaving a total of 6 rows; 2 for each user, like so:
USER_ID SEARCH_TERM count
bob dog 50
bob cat 45
sally cat 38
john mouse 30
sally turtle 10
john zebra 3
In SQL Server, you can put the original query into a CTE, add the ROW_NUMBER() function. Then in the new main query, just add a WHERE clause to limit by the row number. Your query would look something like this:
;WITH OriginalQuery AS
(
SELECT
s.[User_id]
,s.Search_Term
,COUNT(*) AS 'count'
,ROW_NUMBER() OVER (PARTITION BY s.[USER_ID] ORDER BY COUNT(*) DESC) AS rn
FROM Search s
GROUP BY s.[User_id], s.Search_Term
)
SELECT oq.User_id
,oq.Search_Term
,oq.count
FROM OriginalQuery oq
WHERE rn <= 2
ORDER BY oq.count DESC
EDIT: I specified SQL Server as the dbms I used here, but the above should be ANSI-compliant and work in Snowflake.
Related
Given a dataset Roster_table as such:
Group ID
Group Name
Name
Phone
42
Red Dragon
Jon
123455678
32
Green Lizard
Liz
932143211
19
Blue Falcon
Ben
134554678
42
Red Dragon
Reed
432143211
42
Red Dragon
Brad
231314155
19
Blue Falcon
Chad
214124412
How do I get the following query output combining rows with the same Group ID from the dataset, and the new column Count in descending order:
Group ID
Group Name
Count
42
Red Dragon
3
19
Blue Falcon
2
32
Green Lizard
1
SELECT * FROM Roster_table
Please try this where alias tot_count is used in ORDER BY clause.
-- PostgreSQL(v11)
SELECT Group_ID
, MAX(Group_Name) Group_Name
, COUNT(1) tot_count
FROM Roster_table
GROUP BY Group_ID
ORDER BY tot_count DESC;
Please check from url https://dbfiddle.uk/?rdbms=postgres_11&fiddle=b66f9f0d40e804e89be12e3530fe00a0
Based on Rahul Biswas's answer:
Solution without using Max function
SELECT Group_ID, Group_Name, COUNT(*)
FROM Roster_table
GROUP BY Group_ID, Group_Name
ORDER BY COUNT(*) DESC
Credit goes to Eric S.
The simple SELECT query would return the data as below:
Select ID, User, Country, TimeLogged from Data
ID User Country TimeLogged
1 Samantha SCO 10
1 John UK 5
1 Andrew NZL 15
2 John UK 20
3 Mark UK 10
3 Mark UK 20
3 Steven UK 10
3 Andrew NZL 15
3 Sharon IRL 5
4 Andrew NZL 25
4 Michael AUS 5
5 Jessica USA 30
I would like to return a sum of time logged for each user grouped by ID
But for only ID numbers where both of these values Country = UK and User = Andrew are included within their rows.
So the output in the above example would be
ID User Country TimeLogged
1 John UK 5
1 Andrew NZL 15
3 Mark UK 30
3 Steven UK 10
3 Andrew NZL 15
First you need to identify which IDs you're going to be returning
SELECT ID FROM MyTable WHERE Country='UK'
INTERSECT
SELECT ID FROM MyTable WHERE [User]='Andrew';
and based on that, you can then filter to aggregate the expected rows.
SELECT ID,
[User],
Country,
SUM(Timelogged) as Timelogged
FROM mytable
WHERE (Country='UK' OR [User]='Andrew')
AND ID IN( SELECT ID FROM MyTable WHERE Country='UK'
INTERSECT
SELECT ID FROM MyTable WHERE [User]='Andrew')
GROUP BY ID, [User], country;
So, you have described what you need to write almost perfectly but not quite. Your result table indicates that you want Country = UK OR User = Andrew, rather than AND
You need to select and group by, then include a WHERE:-
Select ID, User, Country, SUM(Timelogged) as Timelogged from mytable
WHERE Country='UK' OR User='Andrew'
Group by ID, user, country
I'm new to SQL and sorry if this q has been asked before - I couldn't phrase it properly.
Say I have a table that looks like this:
Name Call ID
Sally 1
Sally 2
Sally 3
Mike 4
Mike 5
Bob 6
Bob 7
I want to create a new table that looks like this:
Name No. of calls
Sally 3
Mike 2
Bob 2
Attempt
I assume I would do something like:
SELECT
Name,
COUNT(distinct Name) AS No. of Calls
FROM Table
Thanks.
You just need to group them and that's all.
SELECT
Name
COUNT(*) AS [No. of Calls]
FROM
Table
GROUP BY
Name
You're looking for GROUP BY:
SELECT Name, COUNT(*) AS 'No. of Calls'
FROM Table
GROUP BY NAME
ORDER BY COUNT(*) DESC
I have a query that creates a result set like this:
Rank Name
1 Fred
1 John
2 Mary
2 Fred
2 Betty
3 John
4 Betty
4 Frank
I need to then select the lowest rank for each name, e.g.:
Rank Name
1 Fred
1 John
2 Mary
2 Betty
4 Frank
Can this be done within TSQL?
SELECT MIN(Rank) AS Rank, Name
FROM TableName
GROUP BY Name
yes
select name, min(rank)
from nameTable
group by name
As Paul + Kevin have pointed out, simple cases of returning a value from an aggregate can be extracted using MIN / MAX etc (just note that RANK is a reserved word)
In a more general / complicated case, e.g. where you need to find the second / Nth highest rank, you can use PARTITIONs with ROW_NUMBER() to do ranking and then filter by the rank.
SELECT [Rank], [Name]
FROM
(
SELECT [RANK], [Name],
ROW_NUMBER() OVER (PARTITION BY [Name] ORDER BY [Rank]) as [RowRank]
FROM [MyTable]
) AS [MyTableReRanked]
WHERE [RowRank] = #N
ORDER BY [Rank];
I am facing a very common issue regarding "Selecting top N rows for each group in a table".
Consider a table with id, name, hair_colour, score columns.
I want a resultset such that, for each hair colour, get me top 3 scorer names.
To solve this i got exactly what i need on Rick Osborne's blogpost "sql-getting-top-n-rows-for-a-grouped-query"
That solution doesn't work as expected when my scores are equal.
In above example the result as follow.
id name hair score ranknum
---------------------------------
12 Kit Blonde 10 1
9 Becca Blonde 9 2
8 Katie Blonde 8 3
3 Sarah Brunette 10 1
4 Deborah Brunette 9 2 - ------- - - > if
1 Kim Brunette 8 3
Consider the row 4 Deborah Brunette 9 2. If this also has same score (10) same as Sarah, then ranknum will be 2,2,3 for "Brunette" type of hair.
What's the solution to this?
If you're using SQL Server 2005 or newer, you can use the ranking functions and a CTE to achieve this:
;WITH HairColors AS
(SELECT id, name, hair, score,
ROW_NUMBER() OVER(PARTITION BY hair ORDER BY score DESC) as 'RowNum'
)
SELECT id, name, hair, score
FROM HairColors
WHERE RowNum <= 3
This CTE will "partition" your data by the value of the hair column, and each partition is then order by score (descending) and gets a row number; the highest score for each partition is 1, then 2 etc.
So if you want to the TOP 3 of each group, select only those rows from the CTE that have a RowNum of 3 or less (1, 2, 3) --> there you go!
The way the algorithm comes up with the rank, is to count the number of rows in the cross-product with a score equal to or greater than the girl in question, in order to generate rank. Hence in the problem case you're talking about, Sarah's grid would look like
a.name | a.score | b.name | b.score
-------+---------+---------+--------
Sarah | 9 | Sarah | 9
Sarah | 9 | Deborah | 9
and similarly for Deborah, which is why both girls get a rank of 2 here.
The problem is that when there's a tie, all girls take the lowest value in the tied range due to this count, when you'd want them to take the highest value instead. I think a simple change can fix this:
Instead of a greater-than-or-equal comparison, use a strict greater-than comparison to count the number of girls who are strictly better. Then, add one to that and you have your rank (which will deal with ties as appropriate). So the inner select would be:
SELECT a.id, COUNT(*) + 1 AS ranknum
FROM girl AS a
INNER JOIN girl AS b ON (a.hair = b.hair) AND (a.score < b.score)
GROUP BY a.id
HAVING COUNT(*) <= 3
Can anyone see any problems with this approach that have escaped my notice?
Use this compound select which handles OP problem properly
SELECT g.* FROM girls as g
WHERE g.score > IFNULL( (SELECT g2.score FROM girls as g2
WHERE g.hair=g2.hair ORDER BY g2.score DESC LIMIT 3,1), 0)
Note that you need to use IFNULL here to handle case when table girls has less rows for some type of hair then we want to see in sql answer (in OP case it is 3 items).