I have a list of users in a database table called Users (SQL Server 2008 R2). In addition to the user's UserName, there are two fields that classify the user - for simplicity we'll say Department and JobTitle.
| UserName | Department | JobTitle |
------------------------------------------
| Joe | IT | SysAdmin |
| Jim | IT | DBA |
| Jeff | Sales | SalesMgr |
| Mack | Sales | Rep |
I also have a table, ActiveJobs, that lists certain combinations of Department and JobTitle that I actually care about.
| Department | JobTitle |
-----------------------------
| IT | SysAdmin |
| Sales | SalesMgr |
| Sales | Rep |
I want to select each of the records from Users that matches the combination of Department / JobTitle in ActiveJobs. I thought this query would do it:
SELECT Users.*
FROM Users
INNER JOIN ActiveJobs DEP
ON Users.Department = DEP.Department
INNER JOIN ActiveJobs JOB
ON Users.JobTitle = JOB.JobTitle
But that returns the same User record more than once in many cases (which I think is caused by the duplicates in the Department column - but I don't really understand why). For the example above, I'm getting (Joe, Joe, Jim, Mack) even though I was hoping to just get (Joe, Jim, Mack).
What query would get the subset of User records that has a matching combination of Department and JobTitle in Active Jobs?
Put an "AND" in your join clause instead of joining twice.
SELECT Users.*
FROM Users
INNER JOIN ActiveJobs DEP
ON Users.Department = DEP.Department AND Users.JobTitle = DEP.JobTitle
Seems like one join on two attributes would work, rather than two joins on one attribute each. Can you JOIN ON ... AND ... ? (Away from computer)
Related
I have a SQL Server database that has the following three tables - this is simplified for this post.
Stakeholder table (a table that stores a persons personal data... name, address city, state, zip, etc)
Stakeholder_id full_name
---------------------------------------
1 Joe Stakeholder
2 Eric Stakeholder
SH Inquiry table (a table that stores information about when a stakeholder contacts us)
sh_inquiry_id inquiry_link_ID
-----------------------------------------------
1 1
2 1
3 2
Sh Contacts (a table that stores information about when we contact a stakeholder)
sh_contact_id contact_link_id
-----------------------------------------
1 1
2 1
3 2
I want to write a SQL query that shows the stakeholder information once then show all inquiries and all contacts underneath the stakeholder row? is that possible with SQL? So in this case joe stakeholder would be shown once and then there would be 4 rows next (2 inquiries and 2 contacts). Eric stakeholder would be shown once with two rows, 1 inquiry and one contact.
Thanks for any assistance in advance.
As has already been mentioned, you probably want to handle this in your application code. However, you can use a UNION query to sort of do what you want.
With the query below, I changed your latter 2 tables to SH_Inquiry and SH_Contacts (replaced spaces with underscores), which is generally a good habit (it's a bad idea to have spaces in your object names). Also, depending on how your tables are laid out, you might want to merge your Contacts and Inquiry tables (e.g. have one table, with a contact_type field that identifies it as "inbound" or "outbound").
Anyways, using a CTE and union:
WITH Unionized AS
(
SELECT
stakeholder_id,
full_name,
NULL AS contact_or_inquiry,
NULL AS contact_or_inquiry_id
FROM Stakeholder
UNION ALL
SELECT
inquiry_link_id AS stakeholder_id,
NULL AS full_name,
'inquiry' AS contact_or_inquiry,
sh_inquiry_id AS contact_or_inquiry_id
FROM SH_Inquiry
UNION ALL
SELECT
contact_link_id AS stakeholder_id,
NULL AS full_name,
'contact' AS contact,
sh_contact_id AS contact_or_inquiry_id
FROM SH_Contacts
)
SELECT
full_name,
contact_or_inquiry,
contact_or_inquiry_id
FROM Unionized
ORDER BY
stakeholder_id,
contact_or_inquiry,
contact_or_inquiry_id
giving you these results:
+------------------+--------------------+-----------------------+
| full_name | contact_or_inquiry | contact_or_inquiry_id |
+------------------+--------------------+-----------------------+
| Joe Stakeholder | NULL | NULL |
| NULL | contact | 1 |
| NULL | contact | 2 |
| NULL | inquiry | 2 |
| Eric Stakeholder | NULL | NULL |
| NULL | contact | 3 |
| NULL | inquiry | 1 |
| NULL | inquiry | 3 |
+------------------+--------------------+-----------------------+
hopefully someone can help me with the following task:
I hVE got 2 tables Treatment and 'Person'. Treatment contains the dates when treatments for the different persons were started, Person contains personal information, e.g. lastname.
Now I have to find all persons where the duration between the first and last treatment is over 20 years.
The Tables look something like this:
Person
| PK_Person | First name | Name |
_________________________________
| 1 | A_Test | Karl |
| 2 | B_Test | Marie |
| 3 | C_Test | Steve |
| 4 | D_Test | Jack |
Treatment
| PK_Treatment | Description | Starting time | PK_Person |
_________________________________________________________
| 1 | A | 01.01.1989 | 1
| 2 | B | 02.11.2001 | 1
| 3 | A | 05.01.2004 | 1
| 4 | C | 01.09.2013 | 1
| 5 | B | 01.01.1999 | 2
So in this example, the output should be person Karl, A_Test.
Hopefully its understandable what the problem is and someone can help me.
Edit: There seems to be a problem with the formatting, the tables are not displayed correctly, I hope its readable.
SELECT *
FROM person p
INNER JOIN Treatment t on t.PK_Person = p.PK_Person
WHERE DATEDIFF(year,[TREATMENT_DATE_1], [TREATMENT_DATE_2]) > 20
This should do it, it is however untested so will need tweaking to your schema
Your data looks a bit suspicious, because the first name doesn't look like a first name.
But, what you want to do is aggregate the Treatment table for each person and get the minimum and maximum starting times. When the difference is greater than 20 years, then keep the person, and join back to the person table to get the names.
select p.FirstName, p.LastName
from Person p join
(select pk_person, MIN(StartingTime) as minst, MAX(StartingTime) as maxst
from Treatment t
group by pk_person
having MAX(StartingTime) - MIN(StartingTime) > 20*365.25
) t
on p.pk_person = t.pk_person;
Note that date arithmetic does vary between databases. In most databases, taking the difference of two dates counts the number of days between them, so this is a pretty general approach (although not guaranteed to work on all databases).
I've taken a slightly different approach and worked with SQL Fiddle to verify that the below statements work.
As mentioned previously, the data does seem a bit suspicious; nonetheless per your requirements, you would be able to do the following:
select P.PK_Person, p.FirstName, p.Name
from person P
inner join treatment T on T.pk_person = P.pk_person
where DATEDIFF((select x.startingtime from treatment x where x.pk_person = p.pk_person order by startingtime desc limit 1), T.StartingTime) > 7305
First, we need to inner join treatements which will ignore any persons who are not in the treatment table. The where portion now just needs to select based on your criteria (in this case a difference of dates). Doing a subquery will generate the last date a person has been treated, compare that to each of your records, and filter by number of days (7305 = 20 years * 365.25).
Here is the working SQL Fiddle sample.
I can't quite get my head around a SQL query because it is not my forté. I'm trying to select the names of rows in an employees table the id's of which appear in a column salesPersonId of another table, accounts. That is, any employee name which is represented in the accounts table.
ACCOUNT
+----+---------------+
| id | salesPersonID |
+----+---------------+
| 0 | 1020 |
+----+---------------+
| 1 | 1020 |
+----+---------------+
| 2 | 1009 |
+----+---------------+
EMPLOYEE
+------+---------------+
| id | firstName |
+------+---------------+
| 1009 | BILL | <-select his name
+------+---------------+
| 1020 | KATE | <-select her name
+------+---------------+
| 1025 | NEIL | <-not this guy
+------+---------------+
Since Neil hasn't got any presence in account.salesPersonID, I'd like to select the other two besides him. I'm not getting very far with it though, and looking for some input.
SELECT * FROM employee e
LEFT JOIN account a
ON a.salesPersonID = e.id
WHERE (SELECT COUNT(salesPersonID) FROM account) > 0
does not work. I wonder how I could select these employee names that are present in salesPersonID. Thank you.
Try this:
SELECT Distinct e.firstName
FROM employee e
JOIN account a ON a.salesPersonID = e.id
The JOIN will take care of the filtering to make sure that you are only returning the records that exist in both tables.
Distinct will make sure that you are only getting each firstName value one time. You can also accomplish this by Grouping by employee.Id or employee.firstName (grouping by Id is the better strategy if you want to return one row for each unique employee, even if they have the same first name, grouping on firstName or using distinct is for when you just want one of each unique name, even if the name is used by more than one employee)
u can have the query like this....
select e.firstname from employees1 e left join account a on(e.id=a.salespersonid)
where e.id= a.salespersonid
group by e.firstname
result:
firstname
bill
kate
I am writing an advanced MySQL query that searches a database and retrieves user information. What I am wondering is can I select certain fields if WHERE condition 1 is met and select other fields if WHERE condition 2 is met?
Database: users
------------------------
| user_id | first_name |
------------------------
| 1 | John |
------------------------
| 2 | Chris |
------------------------
| 3 | Sam |
------------------------
| 4 | Megan |
------------------------
Database: friendship
--------------------------------------
| user_id_one | user_id_two | status |
--------------------------------------
| 2 | 4 | 0 |
--------------------------------------
| 4 | 1 | 1 |
--------------------------------------
Status 0 = Unconfirmed
Status 1 = Confirmed
OK, as you can see John & Megan are confirmed friends while Chris & Megan are friends but the relationship is unconfirmed.
The query I am trying to write is as follow: Megan(4) searches for new friends I want all of the users except for the ones she is a confirmed friend with to be returned. So, the results should return 2,3. But since a relationship with user_id 2 exists but is not confirmed, I want to also return the status since an entry in the friendship table does exist between the two. If a user exist but there is no connection in the relationship table it still returns that users information but returns status as a NULL or doesn't return status at all since it doesn't exist in that table.
I hope this makes since. Ask questions if you need to.
Why not use a left join or an if-not-exists?
SELECT users.*
FROM (users LEFT JOIN friendships
ON status=1 AND (user_id_one=user_id OR user_id_two=user_id) )
WHERE
status IS NULL
or
SELECT users.*
FROM users
WHERE
NOT EXISTS (SELECT *
FROM friendships
WHERE status=1
AND (user_id_one=user_id
OR user_id_two=user_id))
You can create to separate queries and then UNION the result tables. In each query, add a field that always has the same value.
So something like this should work:
(SELECT id, 'Not Friends' As Status FROM t1 WHERE condition1)
UNION
(SELECT id, 'Unconfirmed' As Status FROM t1 WHERE condition2)
Just make sure the same number and name of fields exists in both queries.
I've an old table like this:
user> id | name | address | comments
And now I've to create an "alias" table to allow some users to have an alias name for some reasons. I've created a new table 'user_alias' like this:
user_alias> name | user
But now I have a problem due my poor SQL level... How to join both tables to generate something like this:
1 | my_name | my_address | my_comments
1 | my_alias | my_address | my_comments
2 | other_name | other_address | other_comments
I mean, I want to make a "SELECT..." query that returns in the same format as the "user" table ALL users and ALL alias.. Something like this:
SELECT user.* FROM user LEFT JOIN user_alias ON `user`=`id`
but it doesn't work for me..
I think you need something like this:
SELECT user.*
FROM user
LEFT JOIN user_alias
ON user.name=user_alias.name
Your original query was not specific enough in the join condition.
Something like
SELECT user.name, user.address, user.comment FROM user
UNION ALL
SELECT user_alias.alias, user.address, user.comment
FROM user INNER JOIN user_alias on user.name = user_alias.name
ORDER BY name
will get you close to what you want.
You need to UNION two SELECTs together because the LEFT JOIN solution proposed by others will include only one row in the result set for users with aliases, not two as specified in your question.
But you should make the common column joining user and alias the id column, not the name column.
SELECT user.* FROM user LEFT JOIN user_alias ON user.name = user_alias.name
First of all - the query you want to build is not trivial, because you are trying to get some results spanned across more than one row. So I will offer you a proper solution in a fashion like it should be (read: in a way a database developer will do this :-).
First, you should modify your user_alias table so that it will contain id column but not the name. It is not good idea to join your tables using the name field. The reason for this is that there could be two Sarah Connors.
Then, you can get results from both tables using this query:
SELECT user.*, user_alias.*
FROM user LEFT JOIN user_alias
ON user.id=user_alias.id
This way you will get your results in such format:
id | name | address | comments | user
-------------------------------------------------------------
1 | Sarah Connor | Planet Earth | Nice woman | sarah_connor
2 | Sarah Connor | USA, NY | Mean woman | sarah_c
3 | John Connor | USA, NY | n00b | john123
In the situations when there are two or more records in user_alias table for the same person (equal id's), you will get something like this:
id | name | address | comments | user
-------------------------------------------------------------
4 | Bill Clinton | White House | President | bill
4 | Bill Clinton | White House | President | monica