I have three tables
Student
studenid stuname
101 john
102 aron
103 mary
104 lucy
Subject
studenid subjid subjname
101 1 maths
102 2 science
103 3 computer
104 4 english
Marks
subjid mark
1 50
2 40
3 55
4 60
1 40
2 55
3 60
I want output like this where studenid (sum of mark as total)
studenid stuname mark
101 john 90
102 aron 95
103 mary 115
104 lucy 60
Thank you in advance for yout help, i want output like this even join query or subquery which is best for timing
This just requires a straight left join across all tables, with an aggregation by student.
SELECT
st.studenid,
st.stuname,
COALESCE(SUM(m.mark), 0) AS mark
FROM Student st
LEFT JOIN Subject su
ON st.studenid = su.studenid
LEFT JOIN Marks m
ON su.subjid = m.subjid
GROUP BY
st.studenid,
st.stuname;
Demo
Note that if studenid be a primary key in the Student table, then strictly we would only need to aggregate by this column alone.
Related
I probably haven't explained this very well in the title but I have two tables. Here is a simple version.
channel_data
entry_id channel_id first_name last_name model other_fields
1 4 John Smith
2 4 Jane Doe
3 4 Bill Evans
4 15 235
5 15 765
6 15 543
7 15 723
8 15 354
9 15 976
10 1 xxx
11 2 yyy
12 3 123
channel_titles
entry_id author_id channel_id
1 101 4
2 102 4
3 103 4
4 101 15
5 101 15
6 101 15
7 102 15
8 102 15
9 103 15
10 101 1
11 102 2
12 103 3
I am not able to re-model the data unfortunately.
I need to list all the rows with a channel_id 15 from channel_data and beside them the first_name and last_name which has the same author_id from channel_titles.
What I want to return is this:
Model First Name Last Name
---------------------------------
235 John Smith
765 John Smith
543 John Smith
723 Jane Doe
354 Jane Doe
976 Bill Evans
If Model was in one table and Names were in another this would be much simpler but I'm not sure how to go about this when they are in the same table.
========================================
Edited to clarify.
I need to get each model with a channel_id 15 from channel_data
For each model I need to look up the entry_id in channel_titles to find the author_id
I need to find the row with that author_id AND channel_id 4 in channel titles (each row with channel_id 4 has a unique author_id).
I need to take the entry_id of this row back to channel_data and get the first_name and last_name to go with the model.
I am well aware that the data is not structured well but that is what I have to work with. I am trying to accomplish a very small task in a much larger system, remodelling the data is not an option at this point.
I think sub-queries might be what I am looking for but this is not my area at all usually.
Ok, that is convoluted. However, based on your description, this query should give you the results you want. The WHERE and JOIN descriptions follow the logic you have described in your question.
SELECT cd1.model, cd2.first_name, cd2.last_name
FROM channel_data cd1
JOIN channel_titles ct1 ON ct1.entry_id = cd1.entry_id
JOIN channel_titles ct2 ON ct2.channel_id = 4 AND ct2.author_id = ct1.author_id
JOIN channel_data cd2 ON cd2.entry_id = ct2.entry_id
WHERE cd1.channel_id = 15
ORDER BY cd1.entry_id
Output:
model first_name last_name
235 John Smith
765 John Smith
543 John Smith
723 Jane Doe
354 Jane Doe
976 Bill Evans
Demo on SQLFiddle
Student
_______________________
SudentId Name
101 Peter
103 John
112 James
116 Peter
117 Peter
SudentId_Subject
_______________________
SudentId Subject
101 Physics
103 Chemistry
112 Mathematics
116 Physics
117 Commerce
To find duplicate students, I tried the query
select * from Student group by Name having count(*)>1, got
SudentId Name
_______________________
101 Peter
116 Peter
117 Peter
Actually I need to filter students with the same subject. ie,
101 Peter
116 Peter
are duplicates (same subject) but not 117 Peter
How can I write query for this?
I may have over complicated things, but couldn't think of an easier way :
SELECT ss.student_id,ss.name
FROM student ss
JOIN studentid_subject tt
ON(ss.student_id = tt.student_id)
JOIN(SELECT t.name,s.department
FROM student t
JOIN studentid_subject s
ON(t.student_id = s.student_id)
GROUP BY t.name,s.department
HAVING COUNT(*) > 1) p
ON(ss.name = p.name and tt.department = p.department)
select * from student left join SudentId_Subject on Student.SudentId = SudentId_Subject.DepId where Student.SudentId=SudentId_Subject.DepId
Need to fetch data from master table based on child table condition.
Master Table:-
ID Name Address
1 abc xyz
2 abs txt
3 aui tre
4 pop top
5 the tre
6 pot tos
7 pog sop
8 pat top
9 bat cric
10 not kot
Child Table:-
chid shootid imagename IDFK
101 234 123ab.jpg 3
102 234 54abcab.jpg 3
103 235 123abc.jpg 3
104 236 12390acb.jpg Null
105 235 12332aab.jpg 8
106 234 123786ab.jpg 4
107 234 54789abcab.jpg 10
108 235 122343abc.jpg 10
109 235 122123acb.jpg 4
110 234 12123aab.jpg 9
111 234 1223ab.jpg Null
112 233 5432abcab.jpg Null
113 235 1239abc.jpg Null
114 236 1238acb.jpg 2
115 236 12356aab.jpg 2
116 236 1235ab.jpg 2
117 236 545abcab.jpg Null
118 237 1233abc.jpg 1
119 237 1223acb.jpg 1
120 237 1123aab.jpg 1
In Child table IDFK is the foreign key and ID in Master table is the primary key of that.
Now i want to show those name from master table that doesn't exist on child table filter on shootid like where childtable.Shootid=234. I tried but not find the desired output.Every time it just return's the same out for different shootid as well.
Please help me and show me the right query for that.
I don't know if I am understand you well or not but I think this is what you want,
Select * from [master] m
where m.ID not in (Select IDFK from detail where shootid=234)
I think this is what you are looking for.
Select distinct m.name from master m LEFT OUTER JOIN child c
ON m.id = c.id and
c.shootid=234
where
c.id is null
Environment PHP 5.3.5 phpMyAdmin 3.3.9
Here's an link of the issue in sqlfiddle
Trying to create a query which filters through a user's message activity. The activity will display the most recent threads based upon message recently added. So I have to consider if the user is the recipient or sender.
I have a query structured but I am having great difficulty on grouping the threads. When I group the threads, the order of the most recent activity is lost.
Here is the query and results which captures the correct order of the last 10 messages but there are duplicate thread_ids. I want to only display the most recent thread based upon the message sent date.
SQL query:
SELECT m.date_sent, m.thread_id, m.message_id, m.sender_id,
upub2.firstname as sender_name, mr.recipient_id,
upub1.firstname as recipient_name
FROM message AS m
JOIN message_recipient AS mr ON mr.message_id = m.message_id
JOIN user_public_info AS upub1 ON upub1.user_public_info_id = mr.recipient_id
join user_public_info AS upub2 ON upub2.user_public_info_id = m.sender_id
WHERE ((m.senderDelete IS NULL OR m.senderDelete = 0) AND m.sender_id = 2 ) OR
((mr.is_delete IS NULL OR mr.is_delete = 0 ) AND mr.recipient_id = 2)
ORDER BY m.message_id;
Results:
date_sent thread_id message_id sender_id sender_name recipient_id recipient_name
2013-10-09 14:31:50 106 113 1 John 2 Mark
2013-10-09 14:30:50 107 112 2 Mark 1 John
2013-10-09 14:30:31 106 111 2 Mark 1 John
2013-10-09 09:49:58 112 110 1 John 2 Mark
2013-10-09 09:20:24 108 106 1 John 2 Mark
2013-10-07 15:46:15 107 105 1 John 2 Mark
2013-10-07 14:40:25 103 104 1 John 2 Mark
2013-10-07 14:39:37 103 103 1 John 2 Mark
2013-10-07 14:36:34 107 102 2 Mark 1 John
2013-10-07 14:36:07 106 101 2 Mark 1 John
2013-10-07 14:35:29 105 100 2 Mark 1 John
2013-10-07 12:32:50 104 99 2 Mark 1 John
2013-10-07 12:15:43 104 98 2 Mark 1 John
2013-10-07 11:46:36 104 97 2 Mark 1 John
2013-10-07 11:43:32 104 96 1 John 2 Mark
2013-10-07 11:43:17 104 95 1 John 2 Mark
2013-10-07 11:27:14 103 94 1 John 2 Mark
What I want is this:
date_sent thread_id message_id sender_id sender_name recipient_id recipient_name
2013-10-09 14:31:50 106 113 1 John 2 Mark
2013-10-09 14:30:50 107 112 2 Mark 1 John
2013-10-09 09:49:58 112 110 1 John 2 Mark
2013-10-09 09:20:24 108 106 1 John 2 Mark
2013-10-07 14:40:25 103 104 1 John 2 Mark
2013-10-07 14:35:29 105 100 2 Mark 1 John
2013-10-07 12:32:50 104 99 2 Mark 1 John
Can this be done in one single query or should I create another query based upon the results of the first query?
Thank you for anyone that can help me solve this query....
Your various data sets, queries, and results do not appear to correspod with one another so it's a little difficult to follow, but I suspect you're after something along these lines...
SELECT m.message_id m_id
, m.sender_id s_id
, m.thread_id t_id
, m.subject
, m.message
, m.date_sent
, s.firstname sender
, r.firstname recipient
FROM message m
JOIN message_recipient n
ON n.message_id = m.message_id
JOIN user_public_info s
ON s.user_public_info_id = m.sender_id
JOIN user_public_info r
ON r.user_public_info_id = n.recipient_id
JOIN (SELECT thread_id, MAX(max_message_id) max_message_id FROM message GROUP BY thread_id)x
ON x.thread_id = m.thread_id AND x.max_message_id = m.message_id;
My two tables are
Entry
event_id competitor_id place
101 101 1
101 102 2
101 201 3
101 301 4
102 201 2
103 201 3
second table lists prizes on offer for the events
Prize
event_id place money
101 1 120
101 2 60
101 3 30
102 1 10
102 2 5
102 3 2
103 1 100
103 2 60
103 3 40
From this I am looking to show all the information from the Entry table alongside the amount of money they won for their respected placing. If they failed to place in the money then a 0 will be displayed.
Any help would be appreciated.
try this:
SELECT a.Event_ID,
a.Competitor_ID,
a.Place,
COALESCE(b.money, 0) as `Money`
FROM entry a left join prize b
on (a.event_id = b.event_ID) AND
(a.place = b.Place)
hope this helps.
EVENT_ID COMPETITOR_ID PLACE MONEY
101 101 1 120
101 102 2 60
101 201 3 30
101 301 4 0 -- << this is what you're looking for
102 201 2 5
103 201 3 40
Try this:
select e.*, coalesce(p.money, 0) money from entry e
left join prize p
on e.event_id = p.event_id and e.place = p.place
You can play with the fiddle here.
SELECT * FROM Entry NATURAL LEFT JOIN Prize;
If you absolutely want 0 instead of NULL for the "money" when no prize was won (but how can you differentiate between a prize of 0 and no prize?):
SELECT Entry.*, COALESCE(money, 0) AS money FROM Entry NATURAL LEFT JOIN Prize;
See them both on sqlfiddle.