This is my SQL query:
Select
FirstName,
MiddleName,
LastName,
MatchType,
RunsScored
From
(Select
s.Id,
a.FirstName,
a.MiddleName,
a.LastName,
s.MatchType,
s.RunsScored,
Row_Number() Over(Partition By MatchType Order By RunsScored Desc) rn
From
PlayersCareerBatting s
Join
PlayersBioDataNew a On s.Id = a.Id) x
Where
rn = 1
I want to speed up this query. I'm going to avoid the sub-query for that. Please help me how to avoid sub-query to run query faster.
Related
select users.name
from(
select users.name, pay.uid,
RANK() OVER(ORDER BY count(pay.uid) DESC) AS ranking
from pay, users
where users.uid = pay.uid
group by users.uid)
where ranking = 1
i only want to get users.name output not name,uid,rank.
SELECT sub.name
FROM (SELECT users.name, pay.uid,
RANK() OVER(ORDER BY count(pay.uid) DESC) AS ranking
FROM pay
INNER JOIN users
on users.uid = pay.uid
GROUP BY users.uid) sub
WHERE ranking = 1
alias the inline view (sub)
change alias on outer select to sub instead of pay
The outer query has no knowledge of the tables inside thus the sub alias.
avoid using , for joins that's a 1980s technique the newer standars are to use joins (inner, outer (left, right full), cross etc.)
If I read your problem
You can use this query:
select table.name
from(select users.name, loans.uid, RANK() OVER(ORDER BY count(loans.uid) DESC) AS ranking from loans left join users on users.uid = loans.uid group by users.uid) as 'table'
where ranking = 1
I have these tables with the following columns :
Employee24 (EMPLOYEEID, FIRSTNAME, LASTNAME, GENDER);
PROJECT24 (PROJECTID PROJECTNAME EMPLOYEEID);
I want to write a query to find project to which maximum number of employees are alocated.
SELECT FIRSTNAME, LASTNAME
FROM EMPLOYEE24 E
WHERE E.EMPLOYEEID IN ( SELECT L2.EMPLOYEEID
FROM PROJECT24 L2 group by l2.employeeid)\\
What do you want to do if there are ties? This is an important question and why row_number()/rank() might be a better choice:
select p.*
from (select p.projectid, p.projectname, count(*) as num_employees,
rank() over (order by count(*) desc) as seqnum
from project25 p
group by p.projectid, p.projectname
) p
where seqnum = 1;
Notes:
The above query returns all rows if there are ties. If you want only one (arbitrary) project when there is a tie, then use row_number().
I see no reason to join to employee24.
Your data structure is strange. The relationship between projects and employees should be in a separate table, say project_employees. That should have projectid, but not the name. The name should be in project24.
You might try something like this (though I'm quite sure it can be done in other ways):
SELECT *
FROM (SELECT prj.projectid,
prj.projectname,
COUNT(*) AS number_employees
FROM project24 prj
JOIN employee24 emp
ON prj.employeeid = emp.employeeid
GROUP BY prj.projectid,
prj.projectname
ORDER BY number_employees DESC)
WHERE ROWNUM = 1;
I am having trouble trying to solve this problem, I would like to only add a salary up if the
employee's id is distinct. I thought I could do this using the decode() function but I am having trouble defining an expression suitable. I was aiming for something like
SUM(DECODE(S.ID,IS DISTINCT,S.SALARY))
But this isn't going to work!
So the full query looks like
SELECT B.ID, SUM(S.SALARY), COUNT(DISTINCT S.ID), COUNT(DISTINCT RM.MEMBER_ID)
FROM BRANCH B
INNER JOIN STAFF S ON S.BRANCH_ID = B.ID
INNER JOIN RECRUIT_MEMBER RM ON RM.BRANCH_ID = B.ID
GROUP BY B.ID;
But the problem is with SUM(S.SALARY) it's adding up salaries from duplicate ID's
I don't know about DECODE, but this should work:
SELECT
SUM(S.SALARY)
FROM <table> S
WHERE NOT EXISTS (
SELECT ID FROM <table> WHERE ID=S.ID GROUP BY ID HAVING COUNT(*)>1
)
Perhaps something like this...
SELECT E.ID, SUM(E.Salary)
FROM Employers E
WHERE E.ID IN (SELECT DISTINCT E2.ID FROM Employers E2)
GROUP BY E.ID
If not, perhaps you could post some sample data so that I can understand better
The joins are introducing duplicate rows. One way to fix this is by adding a row number to sequentially identify different ids. The real way would be to fix the joins so this doesn't happen, but here is the first way:
SELECT B.ID, SUM(CASE WHEN SEQNUM = 1 THEN S.SALARY END),
COUNT(DISTINCT S.ID), COUNT(DISTINCT RM.MEMBER_ID)
FROM (SELECT B.ID, S.ID, RM.MEMBER_ID,
ROW_NUMBER() OVER (PARTITION BY S.ID ORDER BY S.ID) as seqnum
FROM BRANCH B
INNER JOIN STAFF S ON S.BRANCH_ID = B.ID
INNER JOIN RECRUIT_MEMBER RM ON RM.BRANCH_ID = B.ID
) t
GROUP BY B.ID
You can create a virtual table with only one salary per ID like this...
SELECT
...whatever fields you've already got...
s.Salary
FROM
...whatever tables and joins you've already got...
LEFT JOIN (SELECT ID, MAX(SALARY) as "Salary" FROM SALARY_TABLE GROUP BY ID) s
ON whatevertable.ID = s.ID
I want to only select the highlighted records. how can i do it in sql and preferably in linq. there is a separate table Emp with EmployeeID as PK.
here is the schema for my tables
I could be way off but I believe following statement satisfies your requirements
SELECT *
FROM (
SELECT e.EmployeeID, h.FromDate, h.ToDate
, rn = ROW_NUMBER() OVER (PARTITION BY e.EmployeeID ORDER BY DesignationID DESC)
FROM employee e
INNER JOIN history h ON h.EmployeeID = e.EmployeeID
) eh
WHERE rn = 1
Try:
select * from
(select t.*,
row_number() over (partition by EmployeeID order by FromDate) as rn) sq
where rn = 1
Can't see exactly what you're asking for. The highlighted ID's are just unique occurrences. So you can do this easily with:
SELECT DISTINCT EmployeeID FROM MyTable
Not sure what you're looking for, but try something like this (no subqueries needed and should work on most DBMS, although it looks like your running SQL Server):
select t1.DisignationHistoryIDs, t1.employeeId, t1.fromDate from history t1
left join history t2
on t1.employeeId = t2.employeeId and t1.fromDate > t2.fromDate
where t2.fromDate is null
This should work to get the oldest fromDate. To get the newest from date just change the > for a <.
Having some problems while trying to optimize my SQL.
I got 2 tables like this:
Names
id, analyseid, name
Analyses
id, date, analyseid.
I want to get the newest analyse from Analyses (ordered by date) for every name (they are unique) in Names. I can't really see how to do this without using 2 x nested selects.
My try (Dont get confused about the names. It's the same principle):
SELECT
B.id,
B.chosendatetime,
vStockNames.name
FROM
vStockNames
INNER JOIN
(
SELECT TOP 1
vAnalysesHistory.id,
vAnalysesHistory.chosendatetime,
vAnalysesHistory.companyid
FROM
vAnalysesHistory
ORDER BY
vAnalysesHistory.chosendatetime DESC
) AS B
ON
B.companyid = vStockNames.stockid
In my example the problem is that i only get 1 row returned (because of top 1). But if I exclude this, I can get multiple analyses of the same name.
Can you help me ? - THanks in advance.
SQL Server 2000+:
SELECT (SELECT TOP 1
a.id
FROM vAnalysesHistory AS a
WHERE a.companyid = n.stockid
ORDER BY a.chosendatetime DESC) AS id,
n.name,
(SELECT TOP 1
a.chosendatetime
FROM vAnalysesHistory AS a
WHERE a.companyid = n.stockid
ORDER BY a.chosendatetime DESC) AS chosendatetime
FROM vStockNames AS n
SQL Server 2005+, using CTE:
WITH cte AS (
SELECT a.id,
a.date,
a.analyseid,
ROW_NUMBER() OVER(PARTITION BY a.analyseid
ORDER BY a.date DESC) AS rk
FROM ANALYSES a)
SELECT n.id,
n.name,
c.date
FROM NAMES n
JOIN cte c ON c.analyseid = n.analyseid
AND c.rk = 1
...without CTE:
SELECT n.id,
n.name,
c.date
FROM NAMES n
JOIN (SELECT a.id,
a.date,
a.analyseid,
ROW_NUMBER() OVER(PARTITION BY a.analyseid
ORDER BY a.date DESC) AS rk
FROM ANALYSES a) c ON c.analyseid = n.analyseid
AND c.rk = 1
You're only asking for the TOP 1, so that's all you're getting. If you want one per companyId, you need to specify that in the SELECT on vAnalysesHistory. Of course, JOINs must be constant and do not allow this. Fortunately, CROSS APPLY comes to the rescue in cases like this.
SELECT
B.id,
B.chosendatetime,
vStockNames.name
FROM
vStockNames
CROSS APPLY
(
SELECT TOP 1
vAnalysesHistory.id,
vAnalysesHistory.chosendatetime,
vAnalysesHistory.companyid
FROM
vAnalysesHistory
WHERE companyid = vStockNames.stockid
ORDER BY
vAnalysesHistory.chosendatetime DESC
) AS B
You could also use ROW_NUMBER() to do the same:
SELECT
B.id,
B.chosendatetime,
vStockNames.name
FROM
vStockNames
INNER JOIN
(
SELECT
vAnalysesHistory.id,
vAnalysesHistory.chosendatetime,
vAnalysesHistory.companyid,
ROW_NUMBER() OVER (PARTITION BY companyid ORDER BY chosendatetime DESC) AS row
FROM
vAnalysesHistory
) AS B
ON
B.companyid = vStockNames.stockid AND b.row = 1
Personally I'm a fan of the first approach. It will likely be faster and is easier to read IMO.
Will something like this work for you?
;with RankedAnalysesHistory as
(
SELECT
vah.id,
vah.chosendatetime,
vah.companyid
,rank() over (partition by vah.companyid order by vah.chosendatetime desc) rnk
FROM
vAnalysesHistory vah
)
SELECT
B.id,
B.chosendatetime,
vsn.name
FROM
vStockNames vsn
join RankedAnalysesHistory as rah on rah.companyid = vsn.stockid and vah.rnk = 1
It seems to me that you only need SQL-92 for this. Of course, explicit documentation of the joining columns between the tables would help.
Simple names
SELECT B.ID, C.ChosenDate, N.Name
FROM (SELECT A.AnalyseID, MAX(A.Date) AS ChosenDate
FROM Analyses AS A
GROUP BY A.AnalyseID) AS C
JOIN Analyses AS B ON C.AnalyseID = B.AnalyseID AND C.ChosenDate = B.Date
JOIN Names AS N ON N.AnalyseID = C.AnalyseID
The sub-select generates the latest analysis for each company; the join with Analyses picks up the Analyse.ID value corresponding to that latest analysis, and the join with Names picks up the company name. (The C.ChosenDate in the select-list could be replaced by B.Date AS ChosenDate, of course.)
Complicated names
SELECT B.ID, C.ChosenDateTime, N.Name
FROM (SELECT A.CompanyID, MAX(A.ChosenDateTime) AS ChosenDateTime
FROM vAnalysesHistory AS A
GROUP BY A.CompanyID) AS C
JOIN vAnalysesHistory AS B ON C.CompanyID = B.CompanyID
AND C.ChosenDateTime = B.ChosenDateTime
JOIN vStockNames AS N ON N.AnalyseID = C.AnalyseID
Same query with systematic renaming (and slightly different layout to avoid horizontal scrollbars).