Get value of one column based on another column in same table - sql

Here is what I am trying to do: Get all people with the same boss and email the boss. I can only use the table below and I would like to add another column showing the boss email which is found in the table.
id name email boss
-------------------------------------------
1 Apple Apple#alo.com Rita
2 Bob Bob#alo.com Rita
3 Charlie Charlie#alo.com Nuna
4 Dan Dan#alo.com Rita
5 Rita Rita#alo.com Sheeba
6 Nuna Nuna#alo.com Sheeba
Thanks for any help.

You use a join to do that. It looks like the code below. When joining to the same table you have to use an alias.
SELECT base.name, boss.email as boss_email
from the_table_name_you_did_not_say as base
join the_table_name_you_did_not_say as boss on base.boss = boss.name
Technically you don't have to use an alias on the base table if you select a wildcard * for some platforms

Related

Strict Match Many to One on Lookup Table

This has been driving me and my team up the wall. I cannot compose a query that will strict match a single record that has a specific permutation of look ups.
We have a single lookup table
room_member_lookup:
room | member
---------------
A | Michael
A | Josh
A | Kyle
B | Kyle
B | Monica
C | Michael
I need to match a room with an exact list of members but everything else I've tried on stack overflow will still match room A even if I ask for a room with ONLY Josh and Kyle
I've tried queries like
SELECT room FROM room_member_lookup
WHERE member IN (Josh, Michael)
GROUP BY room
HAVING COUNT(1) = 2
However this will still return room A even though that has 3 members I need a exact member permutation and that matches the room even not partials.
SELECT room
FROM room_member_lookup a
WHERE member IN ('Monica', 'Kyle')
-- Make sure that the room 'a' has exactly two members
and (select count(*)
from room_member_lookup b
where a.room=b.room)=2
GROUP BY room
-- and both members are in that room
HAVING COUNT(1) = 2
Depending on the SQL dialect, one can build a dynamic table (CTE or select .. union all) to hold the member set (Monica and Kyle, for example), and then look for set equivalence using MINUS/EXCEPT sql operators.

How to filter logic in SQL where element is not present for one of the user

I have table, and I need to find out the person name who dont have Iphone?
Ex. query should give from the below table as Mike.
I am trying to built logic using group by on name and Items where Item not equal to Iphone or by using 2 table but unable to get the result, can anyone suggest ?
Name
Items
Simon
Iphone
Simon
Tablate
Simon
Watch
Simon
Laptop
Jim
Iphone
Jim
Tablate
Jim
Watch
Jim
Laptop
Mike
Tablate
Mike
Watch
Mike
Laptop
I have table, and I need to find out the person name who dont have Iphone?
Using your table, you can use aggregation:
select name
from t
group by name
having sum(case when item = 'Iphone' then 1 else 0 end) = 0;
The having clause counts the number of rows with iphones. The = 0 says there are none for the name.
I like gordons answer but this might be easier to understand:
select name
from table
where name not in
(select name
from table
where item like 'Iphone')
If you need only a single record for each name go for this at the end:
group by name

Merge SQL Rows in Subquery

I am trying to work with two tables on BigQuery. From table1 I want to find the accession ID of all records that are "World", and then from each of those accession numbers I want to create a column with every name in a separate row. Unfortunately, when I run this:
Select name
From `table2`
Where acc IN (Select acc
From `table1`
WHERE source = 'World')
Instead of getting something like this:
Acc1
Acc2
Acc3
Jeff
Jeff
Ted
Chris
Ted
Blake
Rob
Jack
Jack
I get something more like this:
row
name
1
Jeff
2
Chris
3
Rob
4
Jack
5
Jeff
6
Jack
7
Ted
8
Blake
Ultimately, I am hoping to download the data and somehow use python or something to take each name and count the number of times it shows up with each other name at a given accession number, and furthermore measure the degree to which each pairing is also found with third names in any given column, i.e. the degree to which they share a cohort. So I need to preserve the groupings which exist with each accession number, but I am struggling to find info on how one might do this.
Could anybody point me in the right direct for this, or otherwise is the way I am going about this wise if that is my end goal?
Thanks!
This is not a direct answer to the question you asked. In general, it is easier to handle multiple rows rather than multiple columns.
So, I would recommend that you put each acc value in a separate row and then list the names as an array:
select t2.acc, array_agg(t2.name order by t2.name) as names
from `table2` t2
where t2.acc in (Select t1.acc
From `table1` t1
where t1.source = 'World'
)
group by t2.acc;
Otherwise, you are going to have a challenge just naming the columns in your result set.

SQL selecting where A equals both B and C

name | course
Jay | LAWS0001
Mark | LAWS0002
Sam | LAWS0002
Alice | LAWS0001
Ryan | LAWS0001
Ryan | LAWS0002
Hey guys, I've got this database and I want to only select the names that take both 'LAWS0001' and 'LAWS0002'. So from this example, it should select 'Ryan' because he's the only person to take both courses.
I tried IN operator:
SELECT name
FROM student
WHERE course IN ('LAWS0001', 'LAWS0002')
but this takes everyone because everyone is taking either of the courses.
Is there an operator for my problem?
You can use your existing query, using a GROUP BY clause to COUNT the number of distinct courses each student is taking in the set ('LAWS0001', 'LAWS0002') and only selecting those students where the count is 2:
SELECT name
FROM student
WHERE course IN ('LAWS0001', 'LAWS0002')
GROUP BY name
HAVING COUNT(DISTINCT course) = 2
Demo on SQLFiddle

Exclude entire row based on based on values from another query

I am using MS Access and I have a rather complex situation.
I have Respondents who are linked to varying numbers of different Companies via 2 connecting tables. I want to be able to create a list of distinct customers which excludes any customer associated with Company X.
Here is a pic of the relationships that are involved with the query.
And here is an example of what I'm trying to achieve.
RespondentRef | Respondent Name
8 Joe Bloggs
.
RespondentRef | GroupRef
8 2
.
GroupRef | CompanyRef
2 10
.
CompanyRef | CompanyName
10 Ball of String
I want a query where I enter in 'Ball of String' for the company name, and then it produces a list of all the Respondents (taken from Tbl_Respondent) which completely excludes Respondent 8 (as he is linked to CompanyName: Ball of String).
Tbl_Respondent
RespondentRef | Respondent Name
... ...
7 Bob Carlyle
9 Anton Boyle
I have tried many combinations of subqueries with <> and NOT EXISTS and NOT IN and nothing seems to work. I suspect the way these tables are linked may have something to do with it.
Any help you could offer would be very much appreciated. If you have any questions let me know. (I have made best efforts, but please accept my apologies for any formatting conventions or etiquette faux-pas I may have committed.)
Thank you very much.
EDIT:
My formatted version of Frazz's code is still turning resulting in a syntax error. Any help would be appreciated.
SELECT *
FROM Tbl_Respondent
WHERE RespondentRef NOT IN (
SELECT tbl_Group_Details_Respondents.RespondentRef
FROM tbl_Group_Details_Respondents
JOIN tbl_Group_Details ON tbl_Group_Details.GroupReference = tbl_Group_Details_Respondents.GroupReference
JOIN tbl_Company_Details ON tbl_Company_Details.CompanyReference = tbl_Group_Details.CompanyReference
WHERE tbl_Company_Details.CompanyName = "Ball of String"
)
This should do what you need:
SELECT *
FROM Tbl_Respondent
WHERE RespondentRef NOT IN (
SELECT gdr.RespondentRef
FROM Tbl_Group_Details_Respondent gdr
JOIN Tbl_Group_Details gd ON gd.GroupRef=gdr.GroupRef
JOIN Tbl_Company_Details cd ON cd.CompanyRef=gd.CompanyRef
WHERE cd.CompanyName='Ball of String'
)