If I have the following scenario
Table that store people
id_person, name, age (...)
And a table that stores address of people
id_address, id_person, city
If I run a query like this
select * from people P left join address A on P.id_person = A.id_person
I'm getting id_person === null in result set (because there IS a person, but no address has been recorded it, which is fine).
The null is comming from the table address. Is it possible to solve this without doing select field1, field2, field3 ... (lots os fields)?
Example
Person
id_person Name
1 John
2 Steve
Address
id_address id_person city
1 1 'AnyCity'
When I run a query like this
select * from people P left join address A on P.id_person = A.id_person
where P.name = 'Steve'
His id_person is returning null
You mean you only want the id_person from the people table, not from the address table (which sometimes is NULL)?
select p.id_person, p.name, p.age, a.id_address, a.city
from people P left join address A ON P.id_person = A.id_person
Is it possible to solve this without doing select field1, field2, field3 ... (lots os fields)
No - you either use * or identify the fields. You could select all fields from one table and then cherry pick from the other table:
select P.*, A.address, A.City, ...
from people P
left join address A where P.id_person = A.id_person
Related
I want to create a random selected cross-joined table which auto increments its own id and joins on it.
Let's say my tables looking like this.
Person
Firstname, Lastname
Hans | Müller
Joachim | Bugert
Address
City, Street, StreetNumber
Hamburg | Wandsbeckerstr. | 2
Berlin | Konradstraße | 13
Now I want to join the tables with a auto generated ID and they should be random selected.
The final table should look like this
ID,Firstname,Lastname, City, Street, StreetNumber
1 |Hans|Bugert|Berlin|Wandsbeckerstr|2
2|Joachim|Müller|Hamburg|Konradstraße | 13
What I already tried or used:
Here I auto-generate the ID where I want to join the tables on
select GENERATED_PERIOD_START as ID FROM SERIES_GENERATE_INTEGER(1,1,10)
The problem is cross join and inner join isn't working for me because it always joins everything with everything or its not joining on the same ID.
SELECT Person."Firstname", Person."Lastname", Address."City",Address."Street", Address."StreetNumber"
FROM
( select GENERATED_PERIOD_START as ID FROM SERIES_GENERATE_INTEGER(1,1,10)
) autoGenID
inner JOIN
(select "Firstname" ,"Lastname" FROM Person ORDER BY RAND()) Person
inner JOIN
(select "City", "Street", "StreetNumber", FROM Address ORDER BY RAND()) Address
JOIN ON autoGenID."ID"=?????
Here is my problem I can't just select random data and select that on my auto generated ID.
Thanks for your help or ideas how to solve this!
I think you want:
SELECT p."Firstname", p."Lastname", a."City", a."Street", a."StreetNumber"
FROM (SELECT p.*,
ROW_NUMBER() OVER (ORDER BY RAND()) as seqnum
FROM Person p
) p JOIN
(SELECT a.*,
ROW_NUMBER() OVER (ORDER BY RAND()) as seqnum
FROM Address a
) a
ON p.seqnum = a.seqnum;
Can someone help me to figure out how is the best way to do this?
I have a list of people with cars. I need to execute a query that will return people that have a type of car and don't have another type at the same time.
Here is my example:
ID Name CarType
----------- ---------- ----------
1 John MINI VAN
1 John SUV
2 Mary SUV
2 Mary SEDAN
3 Paul SPORT
3 Paul TRUCK
4 Joe SUV
4 Joe MINI VAN
For instance, I want to display only people that have SUV AND DON'T have MINI VAN. If we try the clause CarType IN ('SUV') AND NOT IN ('MINI VAN'), this will not work, because the second statement is just ignored.
In order to return people that have a type but don't have another type at the same time, I tried the following:
Create a temporary table with the IN clause, let's say #Contains
Create a temporary table with the NOT IN clause, let's say #DoesNotContain
Join table with #Contains, this will do the IN clause
On the where clause, look for IDs that are not in #DoesNotContain table.
The query that I am using is this:
--This is the IN Clause
declare #Contains table(
ID int not null
)
--This is the NOT IN Clause
declare #DoesNotContains table(
ID int not null
)
--Select IN
insert into #Contains
SELECT ID from #temp where CarType = 'SUV'
--Select NOT IN
insert into #DoesNotContains
SELECT ID from #temp where CarType = 'MINI VAN'
SELECT
a.ID, Name
FROM
#temp a
INNER JOIN #Contains b on b.ID = a.ID
WHERE
a.ID NOT IN (SELECT ID FROM #DoesNotContains)
Group by
a.ID, Name
This will return Mary because she has a SUV but does not have a MINI VAN.
Here are my questions:
Is it possible to execute this IN and NOT IN in the query, without temp tables? Is there something new in SQL that does that? (Sorry, last time I worked with SQL was SQL 2005)
Should we use temp tables for this?
If this is the way to go, should I use IN and NOT IN instead of the JOIN?
How to replace the NOT IN clause with a JOIN?
Thank y'all!
EDIT
I just tested the solutions but unfortunately I did not specify that I need a combination of cartypes. My bad :(
For instance, if I want all users that have SUV and MINI VAN but not TRUCK AND NOT SEDAN. In this case it only John is returned.
This is normally accomplished with a single query in standard SQL, using NOT EXISTS:
SELECT *
FROM mytable AS t1
WHERE CarType = 'SUV' AND
NOT EXISTS (SELECT *
FROM mytable AS t2
WHERE t1.Name = t2.Name AND t2.CarType = 'MINI VAN')
The above query will select all people having CarType = 'SUV', but do not have CarType = 'MINI VAN'.
Here's one way
SELECT Id, Name
FROM Cars
WHERE CarType = 'SUV'
EXCEPT
SELECT Id, Name
FROM Cars
WHERE CarType = 'MINI VAN'
Or another
SELECT Id, Name
FROM Cars
WHERE CarType IN ('SUV', 'MINI VAN')
GROUP BY Id, Name
HAVING MIN(CarType) = 'SUV'
Or a more generic version that addresses the different requirement in the comment.
SELECT Id,
NAME
FROM Cars
WHERE CarType IN ( 'SUV', 'MINI VAN', 'TRUCK')
GROUP BY Id,
NAME
HAVING COUNT(DISTINCT CASE
WHEN CarType IN ( 'SUV', 'MINI VAN' ) THEN CarType
END) = 2
AND COUNT(DISTINCT CASE
WHEN CarType IN ( 'TRUCK' ) THEN CarType
END) = 0
Using LEFT JOIN:
SELECT a.ID,
Name
FROM #temp a
INNER JOIN #Contains b ON b.ID = a.ID
LEFT OUTER JOIN #DoesNotContains c ON c.ID = a.ID
WHERE c.ID IS NULL
The INNER JOIN will return records where b.ID and a.ID match.
The LEFT OUTER JOIN returns all records, with NULL where there is no match - adding WHERE c.ID IS NULL returns records from a that don't match to c.
The keyword except is your friend. This is the general idea
where carType in
(select carType
from cars
where you want to include them
except
select carType
from cars
where you want to exclude them)
You can work out the details.
I have a SQL table consists of id, name, email,.... I have another SQL table that has id, email, emailstatus but these 2 id are different they are not related. The only thing that is common between these 2 tables are emails.
I would like to join these 2 tables bring all the info from table1 and if the email address from table 1 and table 2 are same and emailstatus is 'Bounced'. But the query that I am writing gives me more record than I expected because there are multiple rows in tbl_webhook(second table) for each row in Applicant(first table) .I want to know if applicant has EVER had an email bounce.
Query without join shows 23000 record but after join shows 42000 record that is because of duplicate how I can keep same 23000 record only add info from second table?
This is my query:
SELECT
A.[Id]
,A.[Application]
,A.[Loan]
,A.[Firstname]
,A.[Lastname]
,A.[Email],
,H.[Email], H.[EmailStatus] as BouncedEmail
FROM Applicant A (NOLOCK)
left outer join [tbl_Webhook] [H] (NOLOCK)
on A.Email = H.Email
and H.[event]='bounced'
this is sample of desired data:
id email name emailFromTable2 emailstatus
1 test2#yahoo.com lili test2#yahoo.com bounced
2 tesere#yahoo.com mike Null Null
3 tedfd2#yahoo.com nik tedfd2#yahoo.com bounced
4 tdfdft2#yahoo.com sam Null Null
5 tedft2#yahoo.com james tedft2#yahoo.com bounced
6 tedft2#yahoo.com San Null
Use a nested select for this type of query. I would write this as:
select id, application, load, firstname, lastname, email,
(case when BouncedEmail is not null then email end) as EmailFromTable2,
BouncedEmail
from (SELECT A.[Id], A.[Application], A.[Loan], A.[Firstname], A.[Lastname], A.[Email],
(case when exists (select 1
from tbl_WebHook h
where A.Email = H.Email and H.[event] = 'bounced'
)
then 'bounced
end) as BouncedEmail
FROM Applicant A (NOLOCK)
) a
You can also do this with cross apply, but because you only really need one column, a correlated subquery also works.
;WITH DistinctEmails
AS
(
SELECT * , rn = ROW_NUMBER() OVER (PARTITION BY [Email] ORDER BY [Email])
FROM [tbl_Webhook]
)
SELECT
A.[Id]
,A.[Application]
,A.[Loan]
,A.[Firstname]
,A.[Lastname]
,A.[Email],
,H.[Email], H.[EmailStatus] as BouncedEmail
FROM Applicant A (NOLOCK) left outer join DistinctEmails [H] (NOLOCK)
on A.Email = H.Email
WHERE H.rn = 1
and H.[event]='bounced'
i believe query below should be enough to select distinct bounced email for you, cheer :)
SELECT
A.[Id]
,A.[Application]
,A.[Loan]
,A.[Firstname]
,A.[Lastname]
,A.[Email],
,H.[Email], H.[EmailStatus] as BouncedEmail
FROM Applicant A (NOLOCK)
Inner join [tbl_Webhook] [H] (NOLOCK)
on A.Email = H.Email
and H.[EmailStatus]='bounced'
basically i just change the joining to inner join and change the 2nd table condition from event to emailstatus, if u can provide your table structure and sample data i believe i can help you up :)
I'm trying to determine a correct way to isolate rows within a table that have the same values in 2 columns.
There are two tables, one (Name) with the person's names and IDs, and the other one (Nation) with people's IDs and their nations. I join the two tables with inner join, and now the new table columns consist of an ID, first name, last name, and nation. If I want to find pairs of people who have the same last name and are from the same nation, why isn't
select ID, FName, LName, Nation
from (Name inner join Nation on Name.ID = Nation.ID)
group by Name, Nation
having count(Name) > 1 and count(Nation) > 1
working?
I'm aiming for the result to be a table with columns:
ID -------First--------------- Last ---------Nation
where the last names and nations will be identical pairs while first names will be different.
I feel like the group by part isnt appropriate, but is there even an alternate way? Thanks for any help.
If you are using MS SQL Server:
select
*
from
(
select
Name.*,
Nation.Nation,
cnt = count(*) over(partition by LName, Nation)
from Name
join Nation on Nation.ID = Name.ID
) t
where cnt > 1
Try this:
SELECT * FROM (
SELECT Name.ID, Name.FName, Name.LName, Nation.Nation
FROM Name
INNER JOIN Nation ON (Name.ID = Nation.ID)
) a
INNER JOIN (
SELECT Name.ID, Name.FName, Name.LName, Nation.Nation
FROM Name
INNER JOIN Nation ON (Name.ID = Nation.ID)
) b ON (a.LName = b.LName AND a.Nation = b.Nation)
WHERE a.ID < b.ID
As Simon Righarts hinted, something's not right with the design.
Scenario 1)
If a name can have multiple nations, you would have 3 tables implementing an n:m relationship.
CREATE TABLE name (name_id int, name text, ...);
CREATE TABLE nation (nation_id int, nation text, ...);
CREATE TABLE nationality (name_id int references name(name_id)
,nation_id int references nation(nation_id)
... );
Query for the scenario:
SELECT a.name_id, a.fname, a.lname, n.nation
FROM name a
JOIN nationality na USING (name_id)
JOIN nation n USING (nation_id)
JOIN (
SELECT a.lname, na.nation_id
FROM name a
JOIN nationality na USING (name_id)
GROUP BY 1,2
HAVING count(*) > 1) x USING (lname, nation_id)
Scenario 2)
If a name can only have one nation, there would be a column nation_id in the table name:
CREATE TABLE name (name_id int
,name text
,nation_id int references nation(nation_id), ...);
CREATE TABLE nation (nation_id int, nation text, ...);
Query for this scenario:
SELECT a.name_id, a.fname, a.lname, n.nation
FROM name a
JOIN nation n USING (nation_id)
JOIN (
SELECT a.lname, a.nation_id
FROM name a
GROUP BY 1,2
HAVING count(*) > 1) x USING (lname, nation_id);
All multiple occurrences are included here, not just "pairs" - assuming you meant that.
Your actual description doesn't fit either scenario.
If I have three columns in my MySQL table people, say id, name, created where name is a string and created is a timestamp.. what's the appropriate query for a scenario where I have 10 rows and each row has a record with a name. The names could have a unique id, but a similar name none the less. So you can have three Bob's, two Mary's, one Jack and 4 Phil's.
There is also a hobbies table with the columns id, hobby, person_id.
Basically I want a query that will do the following:
Return all of the people with zero hobbies, but only check by the latest distinct person created, if that makes sense. Meaning if there is a Bob person that was created yesterday, and one created today.. I only want to know if the Bob created today has zero hobbies. The one from yesterday is no longer relevant.
select pp.id
from people pp, (select name, max(created) from people group by name) p
where pp.name = p.name
and pp.created = p.created
and id not in ( select person_id from hobbies )
SELECT latest_person.* FROM (
SELECT p1.* FROM people p1
WHERE NOT EXISTS (
SELECT * FROM people p2
WHERE p1.name = p2.name AND p1.created < p2.created
)
) AS latest_person
LEFT OUTER JOIN hobbies h ON h.person_id = latest_person.id
WHERE h.id IS NULL;
Try This:
Select *
From people p
Where timeStamp =
(Select Max(timestamp)
From people
Where name = p.Name
And not exists
(Select * From hobbies
Where person_id = p.id))