Considering the tables below, how would I write a query that returns profession.profession when the profession.profession_id is present in contractor_has_profession.profession_id, but limiting it to one result for each profession.profession
So in this example the result would be [Coder, Database, Frontend]
contractor_has_profession
contractor_id | profession_id
1 | 5
2 | 5
3 | 5
4 | 2
5 | 1
profession
profession_id | profession
1 | Frontend
2 | Database
3 | Graphics
4 | Sound
5 | Coder
SELECT p.profession
FROM profession p
WHERE EXISTS(SELECT *
FROM contractor_has_profession c
WHERE c.profession_id = p.profession_id)
Hmm, this should be sufficient:
select distinct p.profession
from profession p
inner join contractor_has_profession c
where p.profession_id = c.profession_id
or if I'm wrong here, then try:
select p.profession
from profession p
inner join contractor_has_profession c
where p.profession_id = c.profession_id
group by p.profession
Related
I have a table (TCAP) containing the gender (2 categories), race/ethnicity (3 categories), and height (integer in inches) for multiple individuals. For example:
GND RCE HGT
1 3 65
1 2 72
2 1 62
1 2 68
2 1 65
2 2 64
1 3 69
1 1 70
I want to get a count of the number of individuals in each possible gender and race/ethnicity combination. When I group by GND and RCE, however, it doesn't show zero counts. I've tried the following code:
SELECT
GND,
RCE,
COUNT(*) TotalRecords
FROM TCAP
GROUP BY GND, RCE;
This gives me:
GND RCE TotalRecords
1 1 1
1 2 2
1 3 2
2 1 2
2 2 1
I want it to show all possible combinations though. In other words, even though there are no individuals with a gender of 1 and race/ethnicity of 3 in the table, I want that to display as a zero count. So, like this:
GND RCE TotalRecords
1 1 1
1 2 2
1 3 2
2 1 2
2 2 1
2 3 0
I've looked at the responses to similar questions, but they are based on a single group, resolved using an outer join with a table that has all possible values. Would I use a similar process here? Would I create a single table that has all 6 combinations of GND and RCE to join on? Is there another way to accomplish this, especially if the number of combinations increases (for example, 1 group with 5 values and 1 group with 10 values)?
Any help would be much appreciated! Thanks!
You can try to use CROSS JOIN make for GND,RCE columns then do OUTER JOIN base on it.
Query #1
SELECT t1.GND,t1.RCE,COUNT(t3.GND) TotalRecords
FROM (
SELECT GND,RCE
FROM (
SELECT DISTINCT GND
FROM TCAP
) t1 CROSS JOIN
(
SELECT DISTINCT RCE FROM TCAP
) t2
) t1
LEFT JOIN TCAP t3 ON t3.GND = t1.GND and t3.RCE = t1.RCE
group by t1.GND,t1.RCE;
| GND | RCE | TotalRecords |
| --- | --- | ------------ |
| 1 | 1 | 1 |
| 1 | 2 | 2 |
| 1 | 3 | 2 |
| 2 | 1 | 2 |
| 2 | 2 | 1 |
| 2 | 3 | 0 |
View on DB Fiddle
Use a cross join to generate the rows and a left join to bring in the results -- with a final group by:
select g.gnd, r.rce, count(t.gnd) as cnt
from (select distinct gnd from tcap) g cross join
(select distinct rce from tcap) r left join
tcap t
on t.gnd = g.gnd and t.rce = r.rce
group by g.gnd, r.rce;
I'm currently working on a select query in T-SQL on SQL Server 2012. It's a complex query, I want to query a list from 3 tables. The result should look something like this:
Desired Output:
ProjectId | Title | Manager | Contact | StatusId
----------+-------------+-----------+-----------+-----------
1 | projectX | 1123 | 4453 | 1
2 | projectY | 2245 | 5567 | 1
3 | projectZ | 3335 | 8899 | 1
My 3 Tables:
1) Project: ProjectId, ProjectDataId, MemberVersionId
2) ProjectData: ProjectDataId, Title, StatusId
3) Members: MemberId, MemberVersionId, MemberTypeId, EmployeeId
The tricky part is, to implement versioning. Thus, over time the project Members can change, and it should always be possible to return to a previous version, that's why I use MemberVersionId as a foreign key inbetween Project and Members. The tables Project and ProjectData a linked with ProjectDataId.
Hence, 1 Project has 1 OfferData and 1 Project has N Members.
Some sample data:
Project
ProjectId | ProjectDataId | MemberVersionId |
----------+---------------+-----------------+
1 | 2 | 1 |
2 | 3 | 1 |
3 | 4 | 1 |
ProjectData
ProjectDataId | Title | StatusId
--------------+-------------+-----------
2 | projectX | 1
3 | projectY | 1
4 | projectZ | 1
Members: MemberTypeId 1 = Manager, MemberTypeId 2 = Contact, 3 = Other
MemberId | MemberVersionId | MemberTypeId | EmployeeId |
---------+-----------------+--------------+------------+
1 | 1 | 1 | 1123 |
2 | 1 | 2 | 4453 |
3 | 1 | 3 | 9999 |
4 | 2 | 1 | 2245 |
5 | 2 | 2 | 5567 |
6 | 2 | 3 | 9999 |
7 | 3 | 1 | 3335 |
8 | 3 | 2 | 8899 |
9 | 3 | 3 | 9999 |
My current query looks like this:
SELECT ProjectId, Title, EmployeeId AS Manager, EmployeeId AS Contact, StatusId
FROM [MySchema].[Project] a,
[MySchema].[ProjectData] b,
[MySchema].[Members] c
WHERE a.ProjectDataId = b.ProjectDataId
AND a.MemberVersionId = c.MemberVersionId
Unfortunately this doesn't work yet. Do you know how to solve this issue?
Thanks
Something like this?
SELECT
p.ProjectId,
pd.Title,
mm.EmployeeId AS Manager,
mc.EmployeeId AS Contact,
pd.StatusId
FROM
[MySchema].[Project] p
INNER JOIN [MySchema].[ProjectData] pd ON pd.ProjectDataId = p.ProjectDataId
INNER JOIN [MySchema].[Members] mm ON mm.MemberVersionId = p.MemberVersionId AND mm.MemberTypeId = 1
INNER JOIN [MySchema].[Members] mc ON mc.MemberVersionId = p.MemberVersionId AND mc.MemberTypeId = 2;
You can try this:
SELECT ProjectId, Title, C.EmployeeId AS Manager, d.EmployeeId AS Contact, StatusId
FROM [MySchema].[Project] a
INNER JOIN [MySchema].[ProjectData] b ON A.ProjectDataId=B.ProjectDataId
LEFT JOIN (SELECT * FROM [MySchema].[Members] WHERE MemberTypeID=1) c ON a.MemberVersionId=c.MemberVersionId
LEFT JOIN (SELECT * FROM [MySchema].[Members] WHERE MemberTypeID=2) d ON a.MemberVersionId=d.MemberVersionId
You must select members two times, one for the manager and another for contact:
SELECT ProjectId, Title, m.EmployeeId AS Manager, c.EmployeeId AS
Contact, StatusId
FROM [MySchema].[Project] a,
[MySchema].[ProjectData] b,
[MySchema].[Members] m
[MySchema].[Members] c
WHERE a.ProjectDataId = b.ProjectDataId
AND a.MemberVersionId = m.MemberVersionId and m.MemberTypeId = 1
AND a.MemberVersionId = c.MemberVersionId and c.MemberTypeId = 2
try this,
SELECT ProjectId, Title, cmanager.EmployeeId AS Manager, ccon.EmployeeId AS
Contact, StatusId
from [MySchema].[ProjectData] b
inner join [MySchema].[Project] a on b.ProjectDataId=a.ProjectDataId
left join [MySchema].[Members] cmanager on cmanager.MemberVersionId =
a.MemberVersionId and cmanager.MemberTypeId=1
left join [MySchema].[Members] ccon on ccon.MemberVersionId =
a.MemberVersionId and ccon.MemberTypeId=2
The simplest solution to your problem would be introducing additional field to Project table. You'd either call it LatestMemberVersion (int, holds the currently highest MemberVersionId), which would by the most up to date version of the relationship, your you can add even simpler IsLatestMemberVersion (bit, holds 1 if the record is the latest/active). You can compute both of them using ROW_NUMBER() OVER statement.
Then, the query would change to:
SELECT ProjectId, Title, EmployeeId AS Manager, EmployeeId AS Contact, StatusId
FROM [MySchema].[Project] a,
[MySchema].[ProjectData] b ON a.ProjectDataId = b.ProjectDataId
[MySchema].[Members] c ON a.MemberVersionId = c.MemberVersionId
WHERE
a.[IsLatestMemberVersion] = 1 -- alternative is a.[LatestMemberVersion] = a.[MemberVersionId]
Additionally, there are two more things you can try:
you might want to borrow ideas from data warehousing, namely you will want to have combination of Slowly Changing Dimension Type 1 and 2
you can try to use SQL Server features, such as Change Data Tracking. But I have no experience with that, so it's possible it'll lead to nowhere.
And one last piece of advice, if you can, never write join conditions into the WHERE clause. It is not readable and can lead to problems when you suddenly change JOIN to LEFT JOIN. Microsoft itself recommends using ON instead of WHERE when applicable.
Example:
Table Question_Answers:
+------+--------+
| q_id | ans_id |
+------+--------+
| 1 | 2 |
| 1 | 4 |
| 2 | 1 |
| 3 | 1 |
| 3 | 2 |
| 3 | 3 |
+------+--------+
User_Submited_Answers:
| q_id | sub_ans_id |
+------+------------+
| 1 | 2 |
| 1 | 4 |
| 2 | 1 |
| 3 | 1 |
| 3 | 2 |
| 3 | 4 |
+------+------------+
I need a T-SQL query if this rows matches count 1 else 0
SELECT
t1.q_id,
CASE WHEN COUNT(t2.sub_ans_id) = COUNT(*)
THEN 1
ELSE 0 END AS is_correct
FROM Question_Answers t1
LEFT JOIN User_Submited_Answers t2
ON t1.q_id = t2.q_id AND
t1.ans_id = t2.sub_ans_id
GROUP BY t1.q_id
Try the following code:
select qa.q_id,case when qa.ans_id=sqa.ans_id then 1 else 0 end as result from questionans qa
left join subquestionans sqa
on qa.q_id=sqa.q_id and qa.ans_id=sqa.ans_id
This should give you expected result for every question.
select q_id, min(Is_Correct)Is_Correct from (
select Q.q_id,case when count(A.sub_ans_id)=count(*) then 1 else 0 end as Is_Correct
from #Q Q left join #A A on Q.q_id=A.q_id and Q.ans_id=A.sub_ans_id
group by Q.q_id
UNION ALL
select A.q_id,case when count(Q.ans_id)=count(*) then 1 else 0 end as Is_Correct
from #Q Q right join #A A on Q.q_id=A.q_id and Q.ans_id=A.sub_ans_id
group by A.q_id ) I group by q_id
MySQL solution (sql fiddle):
SELECT tmp.q_id, MIN(c) as correct
FROM (
SELECT qa.q_id, IF(qa.q_id = usa.q_id, 1, 0) as c
FROM question_answers qa
LEFT JOIN user_submited_answers usa
ON qa.q_id = usa.q_id AND qa.ans_id = usa.sub_ans_id
UNION
SELECT usa.q_id, IF(qa.q_id = usa.q_id, 1, 0) as c
FROM question_answers qa
RIGHT JOIN user_submited_answers usa
ON qa.q_id = usa.q_id AND qa.ans_id = usa.sub_ans_id
) tmp
GROUP BY tmp.q_id;
Now, step by step explanation:
In order to get the right output we will need to:
extract from question_answers table the answers which were not filled in by the user (in your example: q_id = 3 with ans_id = 3)
extract from user_submited_answers table the wrong answers which were filled in by the user (in your example: q_id = 3 with sub_ans_id = 4)
To do that we can use a full outer join (for mysql left join + right join):
SELECT *
FROM question_answers qa
LEFT JOIN user_submited_answers usa
ON qa.q_id = usa.q_id AND qa.ans_id = usa.sub_ans_id
UNION
SELECT *
FROM question_answers qa
RIGHT JOIN user_submited_answers usa
ON qa.q_id = usa.q_id AND qa.ans_id = usa.sub_ans_id;
From the previous query results, the rows which we are looking for (wrong answers) contains NULL values (based on the case, in question_answers table or user_submited_answers table).
The next step is to mark those rows with 0 (wrong answer) using an IF or CASE statement: IF(qa.q_id = usa.q_id, 1, 0).
To get the final output we need to group by q_id and look for 0 values in the grouped rows. If there is at least one 0, the answer for that question is wrong and it should be marked as that.
Check sql fiddle: SQL Fiddle
I have 3 table
**room**
room_id | nurse_needed
----------------------
1 | 2
2 | 3
3 | 1
**doctor_schedule**
doctor_schedule_id| room_id
---------------------------
1 | 1
2 | 2
3 | 3
*nurse_schedule*
nurse_schedule_id | doctor_schedule_id
--------------------------------------
1 | 1
2 | 1
3 | 2
Each Room needs a number of nurse, A doctor work in Room and a nurse work with doctor's schedule. I want to count how many nurse in each room.
The result should be:
room_id | nurse_needed|nurse_have_in_room
---------------------------------------------
1 | 2 | 2
2 | 3 | 1
3 | 1 | 0
Hmmm . . .
select r.*,
(select count(*)
from doctor_schedule ds join
nurse_schedule ns
on ds.doctor_schedule_id = ns.doctor_schedule_id
where ds.room_id = r.room_id
) as nurse_have_in_room
from room r;
select room.*,
(select count(*) from
dotor_schedule docs,
nurse_schedule nurs
where docs.doctor_schedule_id=nurs.dcotor_schedule_id
group by docs.room_id) as nurse_have_in_room
from room;
Result of join on doctor_schedule_id between doctor_schedule and
nurse_schedule
nurse_schedule_id | doctor_schedule_id room_id
--------------------------------------+------------
1 | 1 | 1
2 | 1 | 1
3 | 2 | 2
We group by room_id and then get the result.
select r.room_id,
r.nurse_needed,
ns.nurses_scheduled,
ns.dist_nurses_scheduled
from room r
left join (select ds.room_id,
count(1) nurses_schedule,
count(distinct ns.nurse_schedule_id) dist_nurses_scheduled
from doctor_schedule ds
join nurse_schedule ns
on ds.doctor_schedule_id = ns.doctor_schedule_id
group by ds.room_id) as ns
on r.room_id = ns.room_id
Left join so you find rooms with no nurses scheduled.
Count(distinct ns.nurse_schedule_id) if needed to see how many different nurses make up the count.
Normally you have a time component in there too. Something like "where r.roomdate = ns.date"
I have the following query:
select bb.Name, COUNT(*) as Num from BOutcome bo
JOIN BOffers bb ON bo.ID = bb.BOutcomeID
WHERE bo.EventID = 123 AND bo.OfferTypeID = 321 AND bb.NumA > bb.NumB
GROUP BY bb.Name
The table looks like:
Name | Num A | Num B
A | 10 | 3
B | 2 | 3
C | 10 | 3
A | 9 | 3
B | 2 | 3
C | 9 | 3
The expected output should be:
Name | Count
A | 2
B | 0
C | 2
Because when name is A and C then Num A is bigger to times than Num B and when Name is B, in both records Num A is lower than Num B.
My current output is:
Name | Count
A | 2
C | 2
Because B's output is 0, i am not getting it back in my query.
What is wrong with my query? how should I get it back?
Here is my guess. I think this is a much simpler approach than all of the left/right join hoops people have been spinning their wheels on. Since the output of the query relies only on columns in the left table, there is no need for an explicit join at all:
SELECT
bb.Name,
[Count] = SUM(CASE WHEN bb.NumA > bb.NumB THEN 1 ELSE 0 END)
-- just FYI, the above could also be written as:
-- [Count] = COUNT(CASE WHEN bb.NumA > bb.NumB THEN 1 END)
FROM dbo.BOffers AS bb
WHERE EXISTS
(
SELECT 1 FROM dbo.BOutcome
WHERE ID = bb.BOutcomeID
AND EventID = 123
AND OfferTypeID = 321
)
GROUP BY bb.Name;
Of course, we're not really sure that both Name and NumA/NumB are in the left table, since the OP talks about two tables but only shows one table in the sample data. My guess is based on the query he says is "working" but missing rows because of the explicit join.
Another wild guess. Feel free to downvote:
SELECT ba.Name, COUNT(bb.BOutcomeID) as Num
FROM
( SELECT DISTINCT ba.Name
FROM
BOutcome AS b
JOIN
BOffers AS ba
ON ba.BOutcomeID = b.ID
WHERE b.EventID = 123
AND b.OfferTypeID = 321
) AS ba
LEFT JOIN
BOffers AS bb
ON AND bb.Name = ba.Name
AND bb.NumA > bb.NumB
GROUP BY ba.Name ;