I know there are similar questions like mine but unfortunately I haven't found the corresponding solution to my problem.
First off here's a simplified overview of my tables:
Partner table: PartnerID, Name
Address table: PartnerID, Street, Postcode, City, ValidFrom
Contact table: PartnerID, TypID, TelNr, Email, ValidFrom
A partner can have one or more addresses as well as contact info. With the contact info a partner could have let's say 2 tel numbers, 1 mobile number and 1 email. In the table it would look like this:
PartnerID TypID TelNr Email ValidFrom
1 1 0041 / 044 - 2002020 01.01.2010
1 1 0041 / 044 - 2003030 01.01.2011
1 2 0041 / 079 - 7003030 01.04.2011
1 3 myemail#hotmail.com 01.06.2011
What I need in the end is, combining all tables for each partner, is like this:
PartnerID Name Street Postcode City TelNr Email
1 SomeGuy MostActualStreet MostActualPC MostActualCity MostActual Nr (either type 1 or 2) MostActual Email
Any help?
Here's some T-SQL that gets the answer I think you're looking for if by "Most Actual"
you mean "most recent":
WITH LatestAddress (PartnerID,Street,PostCode,City)
AS (
SELECT PartnerID,Street,PostCode,City
FROM [Address] a
WHERE ValidFrom = (
SELECT MAX(ValidFrom)
FROM [Address] aMax
WHERE aMax.PartnerID = a.PartnerID
)
)
SELECT p.PartnerID,p.Name,la.Street,la.PostCode,la.City
,(SELECT TOP 1 TelNr FROM Contact c WHERE c.PartnerID = p.PartnerID AND TelNr IS NOT NULL ORDER BY ValidFrom DESC) AS MostRecentTelNr
,(SELECT TOP 1 Email FROM Contact c WHERE c.PartnerID = p.PartnerID AND Email IS NOT NULL ORDER BY ValidFrom DESC) AS MostRecentEmail
FROM [Partner] p
LEFT OUTER JOIN LatestAddress la ON p.PartnerID = la.PartnerID
Breaking it down, this example used a common table expression (CTE) to get the latest address information for each Partner
WITH LatestAddress (PartnerID,Street,PostCode,City)
AS (
SELECT PartnerID,Street,PostCode,City
FROM [Address] a
WHERE ValidFrom = (
SELECT MAX(ValidFrom)
FROM [Address] aMax
WHERE aMax.PartnerID = a.PartnerID
)
)
I left-joined from the Partner table to the CTE, because I didn't want partners who don't have addresses to get left out of the results.
FROM [Partner] p
LEFT OUTER JOIN LatestAddress la ON p.PartnerID = la.PartnerID
In the SELECT statement, I selected columns from the Partner table, the CTE, and I wrote two subselects, one for the latest non-null telephone number for each partner, and one for the latest non-null email address for each partner. I was able to do this as a subselect because I knew I was returning a scalar value by selecting the TOP 1.
SELECT p.PartnerID,p.Name,la.Street,la.PostCode,la.City
,(SELECT TOP 1 TelNr FROM Contact c WHERE c.PartnerID = p.PartnerID AND TelNr IS NOT NULL ORDER BY ValidFrom DESC) AS MostRecentTelNr
,(SELECT TOP 1 Email FROM Contact c WHERE c.PartnerID = p.PartnerID AND Email IS NOT NULL ORDER BY ValidFrom DESC) AS MostRecentEmail
I would strongly recommend that you separate your Contact table into separate telephone number and email tables, each with their own ValidDate if you need to be able to keep old phone numbers and email addresses.
Check out my answer on another post which explains how to get the most actual information in a case like yours : Aggregate SQL Function to grab only the first from each group
PS : The DATE_FIELD would be ValidFrom in your case.
Related
I have a table for company phone numbers and one of the columns is IsPrimary which is a boolean type. The table looks like this:
CompanyId | AreaCode | PhoneNumber | IsPrimary
123 212 555-1212 0
234 307 555-1234 1
234 307 555-4321 0
As you can see in the first record, even though the phone number is the only one for CompanyId: 123, it's not marked as the primary.
In such cases, I want my SELECT statement to return the first available number for that company.
My current SELECT statement looks like this which does NOT return a number unless it's set as the primary number.
SELECT *
FROM CompanyPhoneNumbers AS t
WHERE t.IsPrimary = 1
How can I modify this SELECT statement so that it includes the phone number for CompanyId: 123?
The query might be different depending on what you are actually up to.
If you already have the CompanyId and only need the phone number for it, that's easy:
select top (1) pn.*
from dbo.CompanyPhoneNumbers pn
where pn.CompanyId = #CompanyId -- A parameter provided externally, by calling code for instance
order by pn.IsPrimary desc;
However, if you need all companies' data, including one of their phones (for example, you might be going to create a view for this), then you need a correlated subquery:
select c.*, oa.*
from dbo.Companies c
outer apply (
select top (1) pn.*
from dbo.CompanyPhoneNumbers pn
where pn.CompanyId = c.Id
order by pn.IsPrimary desc
) oa;
I have deliberately used outer instead of cross apply, otherwise it will filter out companies with no phone numbers listed.
You can achieve this using an apply statement. This looks at the exact same table and returns the record with the highest IsPrimary so, this would return the records with a 1 in that column. If there are more than one marked as primary or not as primary, then it returns the phone number, with area code, in ascending order.
select b.*
from CompanyPhoneNumbers a
cross apply (
select top 1
*
from CompanyPhoneNumbers b
where b.CompanyId = a.CompanyId
order by b.IsPrimary desc
,b.AreaCode
,b.PhoneNumber
) b
There can be multiple account names assigned to 1 account number. Since there are a million of rows in the DB I want to find out how I can query the account # that is only assigned to 1 account. Please see sample data below:
Account # 100, 100, 500, 650, 250, 250, 600, 400, 400
Account Name ABA, DSA, ABA, DSA, ABA, DSA, DSA, ABA, ABA
The result of the query should be account # 500,650,400 because these account # only have one account name assigned to it.
Account 100 and 250 have multiple account names assigned to it. How do I filter account number with only 1 account name assigned to it? Please help
GROUP BY and HAVING is the way to go as stated in a comment above.
select account_num
from your_table
group by account_num
having COUNT(*) = 1
Some people will frown on the * in COUNT(), but if this is an ad hoc, non-production query, I don't think it's a big deal in terms of performance.
Based on the question, I believe the query should return 400,500,600,650.
Using a query with the clause of having count(*) =1 would not return 400 based on the data given in the question.
create table #Accounts (
AccountNumber int not null
, AccountName char(3) not null
)
insert into #Accounts (AccountNumber,AccountName) values
(100,'ABA')
,(100,'DSA')
,(500,'ABA')
,(650,'DSA')
,(250,'ABA')
,(250,'DSA')
,(600,'DSA')
,(400,'ABA')
,(400,'ABA');
with cte as (
select AccountNumber
, AccountName
, RowNumber= row_number() over (
partition by AccountNumber
order by AccountName
)
from #Accounts
group by AccountNumber, AccountName
)
select AccountNumber
, AccountName
from cte
where not exists (
select 1
from cte as i
where i.AccountNumber = cte.AccountNumber
and i.RowNumber = 2
);
This will return the account no and name where the account no is linked to more than one name
NOTE: In your example data, account no 400 is linked to the same name twice...
I'm not sure it that should count as linked to 1 name or not...
This will include AccountNo 400
SELECT DISTINCT AccountNo, AccountName
FROM #Accounts a
WHERE (
SELECT COUNT(DISTINCT AccountName)
FROM #Accounts b
WHERE a.AccountNo = b.AccountNo) = 1
This will NOT include Account No 400 (No DISTINCT in Sub Query)
SELECT DISTINCT AccountNo, AccountName
FROM #Accounts a
WHERE (
SELECT COUNT(AccountName)
FROM #Accounts b
WHERE a.AccountNo = b.AccountNo) = 1
I have this tables:
tblDiving(
diving_number int primary key
diving_club int
date_of_diving date)
tblDivingClub(
number int primary key not null check (number>0),
name char(30),
country char(30))
tblWorks_for(
diver_number int
club_number int
end_working_date date)
tblCountry(
name char(30) not null primary key)
I need to write a query to return a name of a country and the number of "Super club" in it.
a Super club is a club which have more than 25 working divers (tblWorks_for.end_working_date is null) or had more than 100 diving's in it(tblDiving) in the last year.
after I get the country and number of super club, I need to show only the country's that contains more than 2 super club.
I wrote this 2 queries:
select tblDivingClub.name,count(distinct tblWorks_for.diver_number) as number_of_guids
from tblWorks_for
inner join tblDivingClub on tblDivingClub.number = tblWorks_for.club_number,tblDiving
where tblWorks_for.end_working_date is null
group by tblDivingClub.name
select tblDivingClub.name, count(distinct tblDiving.diving_number) as number_of_divings
from tblDivingClub
inner join tblDiving on tblDivingClub.number = tblDiving.diving_club
WHERE tblDiving.date_of_diving <= DATEADD(year,-1, GETDATE())
group by tblDivingClub.name
But I don't know how do I continue.
Every query works separately, but how do I combine them and select from them?
It's university assignment and I'm not allowed to use views or temporary tables.
It's my first program so I'm not really sure what I'm doing:)
WITH CTE AS (
select tblDivingClub.name,count(distinct tblWorks_for.diver_number) as diving_number
from tblWorks_for
inner join tblDivingClub on tblDivingClub.number = tblWorks_for.club_number,tblDiving
where tblWorks_for.end_working_date is null
group by tblDivingClub.name
UNION ALL
select tblDivingClub.name, count(distinct tblDiving.diving_number) as diving_number
from tblDivingClub
inner join tblDiving on tblDivingClub.number = tblDiving.diving_club
WHERE tblDiving.date_of_diving <= DATEADD(year,-1, GETDATE())
group by tblDivingClub.name
)
SELECT * FROM CTE
You can combine the queries using a UNION ALL as long as there are the same number of columns in each query. You can then roll them into a Common Table Expression (CTE) and do a select from that.
I want to select all records, but have the query only return a single record per Product Name. My table looks similar to:
SellId ProductName Comment
1 Cake dasd
2 Cake dasdasd
3 Bread dasdasdd
where the Product Name is not unique. I want the query to return a single record per ProductName with results like:
SellId ProductName Comment
1 Cake dasd
3 Bread dasdasdd
I have tried this query,
Select distict ProductName,Comment ,SellId from TBL#Sells
but it is returning multiple records with the same ProductName. My table is not realy as simple as this, this is just a sample. What is the solution? Is it clear?
Select ProductName,
min(Comment) , min(SellId) from TBL#Sells
group by ProductName
If y ou only want one record per productname, you ofcourse have to choose what value you want for the other fields.
If you aggregate (using group by) you can choose an aggregate function,
htat's a function that takes a list of values and return only one : here I have chosen MIN : that is the smallest walue for each field.
NOTE : comment and sellid can come from different records, since MIN is taken...
Othter aggregates you might find useful :
FIRST : first record encountered
LAST : last record encoutered
AVG : average
COUNT : number of records
first/last have the advantage that all fields are from the same record.
SELECT S.ProductName, S.Comment, S.SellId
FROM
Sells S
JOIN (SELECT MAX(SellId)
FROM Sells
GROUP BY ProductName) AS TopSell ON TopSell.SellId = S.SellId
This will get the latest comment as your selected comment assuming that SellId is an auto-incremented identity that goes up.
I know, you've got an answer already, I'd like to offer a way that was fastest in terms of performance for me, in a similar situation. I'm assuming that SellId is Primary Key and identity. You'd want an index on ProductName for best performance.
select
Sells.*
from
(
select
distinct ProductName
from
Sells
) x
join
Sells
on
Sells.ProductName = x.ProductName
and Sells.SellId =
(
select
top 1 s2.SellId
from
Sells s2
where
x.ProductName = s2.ProductName
Order By SellId
)
A slower method, (but still better than Group By and MIN on a long char column) is this:
select
*
from
(
select
*,ROW_NUMBER() over (PARTITION BY ProductName order by SellId) OccurenceId
from sells
) x
where
OccurenceId = 1
An advantage of this one is that it's much easier to read.
create table Sale
(
SaleId int not null
constraint PK_Sale primary key,
ProductName varchar(100) not null,
Comment varchar(100) not null
)
insert Sale
values
(1, 'Cake', 'dasd'),
(2, 'Cake', 'dasdasd'),
(3, 'Bread', 'dasdasdd')
-- Option #1 with over()
select *
from Sale
where SaleId in
(
select SaleId
from
(
select SaleId, row_number() over(partition by ProductName order by SaleId) RowNumber
from Sale
) tt
where RowNumber = 1
)
order by SaleId
-- Option #2
select *
from Sale
where SaleId in
(
select min(SaleId)
from Sale
group by ProductName
)
order by SaleId
drop table Sale
Does anyone know how can I add an integer from another table to the current selected table in SQL Server?
For example:
I have 2 tables with the following information in each table
tableA:
id username point status country
1 alvin 1 1 U.S.A
2 alvin 1 1 U.S.A
3 amy 1 0 Australia
tableB:
id username point
1 amy 1
2 alvin 1
3 ken 1
How can I sum up the total points in tableA with also add in the sum points from tableB?
I tried the following code, but seem is not working and error display:
SELECT username, (COUNT(distinct a.point) + (SELECT SUM(a.point)
FROM tableB b WHERE b.username = a.username) AS 'Points', status, country
FROM tableA
GROUP BY aco.username
And the output I expected will be:
username Points status country
alvin 3 1 U.S.A
amy 2 0 Australia
WITH Results(username,point)
AS
(
SELECT username, point FROM TableA
UNION ALL
SELECT username, point FROM TableB
)
SELECT username, sum(point) AS Points FROM Results GROUP BY username
GO
EDIT
The question has changed, so now the solution should look like this
WITH Results(username,point,status, country)
AS
(
SELECT username, point, status, country FROM TableA
UNION ALL
SELECT username, point, null, null FROM TableB
)
SELECT username, sum(point) AS Points, max(status), max(country) FROM Results GROUP BY username
GO
What is WITH ?
What is UNION ?
You don't mention why Ken doesn't appear in the output table, I assume that TableA is the 'master' list. If so I would do the following INNER JOIN which is the most simple solution.
SELECT a.username AS Username, SUM(ISNULL(a.point,0)+ISNULL(b.point,0)) as Points,
MAX(a.Status) as Status, MAX(a.Country) as Country
FROM TableA a
INNER JOIN TableB b
ON a.username=b.username
GROUP BY a.username