SQL query: need help on subquery - sql

Question is as follows:
There are 2 related tables (am giving some sample values for making it simplified):
Circuit
--------
id name
1 a
2 b
3 c
Circuit_Dependent
-----------------
id depend_id
1 2
1 3
the tables are related and second table tells the relation with the circuit id's.
Situation is query needed for:
1) list the circuit name which has the circuit_dependency
output expected:
name dependent_name
a b
a c
2) list the circuit name and count(no of dependancies)
output expected:
name count
a 2
appreciate help.

First query could be:
SELECT c1.`name`, c2.`name`
FROM Circuit_Dependent cd INNER JOIN Circuit c1
ON cd.id = c1.id
INNER JOIN Circuit c2
ON cd.depend_id = c2.id
Second query could be this one:
SELECT c.`name`, COUNT(DISTINCT cd.depend_id) AS count
FROM circuit c INNER JOIN Circuit_Dependent cd
ON c.id = cd.id
GROUP BY c.id

Related

SQL Multiple Joins Query

Here I have two tables committee_colleges and colleges.
Structure of tables is something like this
committee_colleges
committeeCollegeId collegeId committeeMemberId
1 2 1
2 2 2
3 3 2
I am storing committeeMemberId from committeeMember table.And one college can have multiple committee Members.How can I wite a query to display only the colleges assigned to specific committee Member.
For Example,if committeeMember by id=2 has logged in I want to display colleges by id=2,3.
In college table I have like this,
collegeId typeName
1 AICTE
2 NCTE
3 NTCS
This is Committee Member table
committeeMemberId name
1 xyz
2 abc
Now I am writing something like this,but i know its wrong because I dont know how to take it from College table since I am displaying College details.
SELECT cc.committeeCollegeId as committeeCollegeId,
c.collegeId as collegeId,
cc.committeeMemberId as committeeMemberId
FROM committee_college as cc
left outer join College as c
on cc.collegeId = c.collegeId
where cc.committeeMemberId=:committeeMemberId
order by cc.committeeCollegeId asc
Can anyone tell how to display colleges based on its assignment to particular committeeMember?
You were close, you need INNER JOIN instead of LEFT JOIN:
SELECT DISTINCT C.typeName --<<== put here all the columns that you want in output
FROM committee_colleges CC
INNER JOIN college C
ON C.collegeId = CC.collegeId
WHERE CC.committeeMemberId = 2 --<<== your input parameter
EDIT: added DISTINCT
Hope it helps.
You can use below sql statement for the same
DECLARE #committeeMemberId INT = 2 -- Id of Committee member
;WITH CTE_MemberCommittee AS
(
SELECT CollegeId
FROM committee_colleges
WHERE committeeMemberId = #committeeMemberId
)
SELECT collegeId, typeName
FROM college
WHERE collegeId IN (SELECT CollegeId FROM CTE_MemberCommittee)
You can use simple inner join for that,
If you want collegename based on memberId use following query,
select a.collegeid,a.typeName from
college a, committee_colleges b, committe_member c
where a.collegeid = b.collegeid and
b.committeememberid = c.committeeMemberId
and c.committeeMemberId = '2'
If you want collegename based on committemember name then use following query,
select a.collegeid,a.typeName from
college a, committee_colleges b, committe_member c
where a.collegeid = b.collegeid and
b.committeememberid = c.committeeMemberId
and c.Name = 'xyz'
Hope it will help.
try this:
DECLARE #LoginCommitteeMemberId INT=2
SELECT t2.Name AS MemberName,
t3.TypeName AS CollageName
FROM committee_college t1
INNER JOIN Committee_Member t2
ON t1.committeeMemberId = t2.committeeMemberId
INNER JOIN College as t3
ON t1.collegeId = t3.collegeId
WHERE t1.committeeMemberId = #LoginCommitteeMemberId

Get data from relational tables

I have following tables in my db.
Calls:
ID Name
1 Call1
2 Call2
3 Call3
Notes:
ID Name
1 Note 1
2 Note 2
Person:
ID Name
1 Andrew
PersonCalls:
ID CallID PersonID
1 1 1
2 2 1
PersonNotes:
ID NoteID PersonID
1 1 1
1 2 1
Now I need to get data from these tables according to person id. I am able to get data from 2 tables, for example Notes and PersonNotes, but I am not able to get combined data from these tables. This should be the result.
Result:
PersonID Note Call
1 Note1 Call1
1 Note2 Call2
Please suggest
Thanks
Use Join (ie: Inner Join):
select distinct p.ID as PersonID, n.Name as Note, c.Name as Call from Person p
inner join PersonCalls pc on p.ID = pc.PersonID
inner join PersonNotes pn on p.ID = pn.PersonID
inner join Calls c on pc.CallID = c.ID
inner join Notes n on pn.NoteID = n.ID
Without getting too detailed you can use a left join on dbo.calls.ID, dbo.notes.id, dbo.person.id, etc if you are using MS SQL server. Otherwise are you sure you can't just write a report?

Query Handling Sql Server

Please help me regarding query. I am pretty weak in DBMS.
I have a table TBLParent which has some rows as follows
pkParentId FKProductId Name
1 5 P1
2 5 P2
3 3 P3
and I have another table TBLChild that consist of its children
pkId fkParentId ChildName
1 1 C1
2 1 c2
3 2 c1
Now, question is I want Parent records and count of its children based on productId.
For example: I want to
select
TBLParent.pkParentId, TBLParent.FKProductId,
TBLParent.Name,
count of its children
where
TBLParent.FKProductId = 5
I tried like this
Select
count(TBLChild.pkId) AS total,
TBLChild.fkParentId
from
TBLChild
group by
TBLChild.fkParentId
but how can I attach records of parent table with this count?
This will give me count but How I will attach parent record with this count. I mean to say output would be
pkParentId Name Count
1 P1 2
2 P2 1
Please help please help please help?
SELECT P.pkParentId
,P.Name
,COUNT(*)
FROM tblParent P
INNER JOIN tblChild C ON P.pkParentId = C.fkParentId
WHERE P.pkParentId = #yourValueHere
GROUP BY P.pkParentId, P.Name

Joining 3 Tables Using Newest Rows

I have 3 tables in my database: children, families, statuslog
Every time a child is checked in or out of the database, it is updated in the statuslog. I've done this a long time ago, but I can't seem to figure out how to do it anymore. I want to create a new view that joins all 3 tables, but I only want the newest entry from statuslog (by using the highest id).
For example, statuslog looks like this:
childID researcher status id
1 Dr. A out 1
1 Dr. A in 2
1 Dr. B out 3
1 Dr. B in 4
2 Dr. C out 5
2 Dr. C in 6
3 Dr. B out 7
3 Dr. B in 8
This is what I want to do:
SELECT *
FROM children, families, statuslog
WHERE children.familyID = families.familyID AND children.childID = statuslog.childID
Obviously, this will return the children+families tuples coupled with every single log entry, but I can't remember how to only combine it with the newest log entry.
Any help would be appreciated!
Aggregate query with max(id) retrieves last ID given a childID. This is then joined to statuslog to retrieve other columns.
SELECT *
FROM children
INNER JOIN families
ON children.familyID = families.familyID
INNER JOIN
(
SELECT childID, researcher, status
FROM statuslog
INNER JOIN
(
SELECT childID, max(ID) ID
FROM statuslog
GROUP BY childID
) lastSL
ON statuslog.childID = lastSL.childid
AND statuslog.ID = lastSL.ID
) sl
ON children.childID = sl.childID
This seems to be the typical greatest-n-per-group in which the higher id is interpreted as the newest. This query should do the trick:
select * from (
select s1.* from statusLog s1
left join statusLog s2
on s1.childId = s2.childId and s1.id < s2.id
where s2.id is null
) final
join children c on c.childId = final.childId
join families f on f.familyId = c.familyId
Correct any syntactical errors.

Left Outer Join with one result per match and "priority" of match set by a different field in match SQL Server 2005

I am trying to get a single result (PHONE) per match (CONTACT_ID) in a Left Outer Join. I imagine that there is a way to accomplish this with the preference (or order) being set by another column/field- the phone type (TYPE), but I haven't been able to figure it out. Below is a list of facts to help better explain what I am trying to accomplish and then following is an example Table A and B with the desired result. I've looked at min() and group by, but I don't know how to make those work here. As a side note, after this is working, I will be joining it to more tables to the left of it in a simpler fashion.
The student can have an unlimited number of CONTACT_ID.
A contact does not always have all phone types.
The preferred order of phone types (TYPE) is C,H,W (which, fortunately, happens to be alphabetical)
ignore match and go to the next in priority if PHONE is null
TableA:
STUDENT_ID CONTACT_ID
---------- ----------
X 1
X 2
Y 3
Y 4
TableB:
CONTACT_ID TYPE PHONE
---------- ---- -----
1 H 21
1 C
1 W 44
2 H 78
2 C 92
2 W 11
Desired Result:
STUDENT_ID CONTACT_ID TYPE PHONE
---------- ---------- ---- -----
X 1 H 21
X 2 C 92
Y 3
Y 4
Here is the query that I have that will make a join with all phone matches (minus all of my crazy attempts at getting what I want).
SELECT *
FROM Table TableA T1
LEFT OUTER JOIN TableB T2 ON T1.CONTACT_ID = T2.CONTACT_ID
All help greatly appreciated!
Edited code from Stefan Onofrei's solution:
(results in some duplicate entries)
SELECT
T1.STUDENT_ID,
T1.CONTACT_ID,
T2.PHONE_TYPE,
T3.PHONE
FROM REG_STU_CONTACT T1
INNER JOIN
(SELECT MIN(PHONE_TYPE) AS PHONE_TYPE, CONTACT_ID
FROM REG_CONTACT_PHONE
WHERE PHONE IS NOT NULL
GROUP BY CONTACT_ID) T2 ON T1.CONTACT_ID = T2.CONTACT_ID
INNER JOIN REG_CONTACT_PHONE T3 ON T2.CONTACT_ID = T3.CONTACT_ID AND T2.PHONE_TYPE = T3.PHONE_TYPE
ORDER BY T1.STUDENT_ID
Select A.STUDENT_ID A.CONTACT_ID B.TYPE c.PHONE
from TableA A
inner join
(select MIN(type ) as type, Contact_ID
from Tableb
where phone is not null
group by contactid) B
on A.contactid = b.contactid
inner join Tableb C
on B.contactid = c.conatctid and b.type = c.type