I am trying to get all the values from the first left table but when I use two left joins its restricting the values from first table.
I used the below query
SELECT P.person_id, TS.Task_Id, TS.skill
FROM Person P
LEFT JOIN Person_Skill PS ON P.person_id = PS.person_id
LEFT JOIN Task_Skill TS ON PS.Skill = TS.Skill
WHERE ts.task_id = 245
I need all the person id from person table.
Just move the condition on the left joined table from the where clause to the on clause of the join:
select p.person_id, ts.task_id, ts.skill
from person p
left join person_skill ps
on p.person_id = ps.person_id
left join task_skill ts
on ps.skill = ts.skill
and ts.task_id = 245 --> here
Rationale: conditions in the where clause are mandatory. If there is no match in ts, then condition ts.task_id = 245 cannot be satisfied, since ts.task_id is null.
Use the filter condition in a sub query instead of using it as a global filter outside. This should give you the output that you desire.
SELECT P.person_id,TS.Task_Id,TS.skill FROM Person P
LEFT JOIN Person_Skill PS
ON P.person_id=PS.person_id
LEFT JOIN
(Select * from Task_Skill where task_id = 245) TS
ON PS.Skill=TS.Skill;
Related
Can someone help me with this? I am new to SQL.
I want to return one record for every record in Product_Entity.
Product_Entity is linked to Entity_Varchar by the common coilumn entity_id.
I want each record in the results to include Entity_Varchar.value, but only when Entity_Varchar.attribute_id = ‘73’ as there will be many records in Entity_Varchar that will match on entity_id, but only one where also Entity_Varchar.attribute_id=’73’
SELECT
Product_Entity.sku AS SKU,
Entity_Varchar.value AS Description
FROM
Product_Entity
JOIN
Entity_Varchar ON Entity_Varchar.entity_id = Entity_Varchar.entity_id
WHERE
Entity_Varchar.attribute_id = '73'
Your query basically looks right. However, if you want all rows in the first table, then use a LEFT JOIN:
SELECT pe.sku AS SKU, ev.value AS Description
FROM Product_Entity pe LEFT JOIN
Entity_Varchar ev
ON ev.entity_id = pe.entity_id AND
ev.attribute_id = '73';
Rows that don't match will have NULL for the description.
Your query is correct you just misspelled table name. Instead of Product_Entity you used Entity_Varchar in both side of on clause.
Corrected query:
SELECT Product_Entity.sku AS SKU, Entity_Varchar.value AS Description FROM Product_Entity inner Join Entity_Varchar
ON Product_Entity.entity_id = Entity_Varchar.entity_id
WHERE Entity_Varchar.attribute_id = '73'
For better readability you can use table aliaces.
SELECT pe.sku AS SKU, ev.value AS Description
FROM Product_Entity pe inner Join Entity_Varchar ev
ON pe.entity_id = ev.entity_id
WHERE ev.attribute_id = '73'
If you want to select rows from Product_Entity table even when there is no row in Entity_Varchar table with same entity_id and for attribute_id 73 you need to use left join instead of inner join.
SELECT pe.sku AS SKU, ev.value AS Description
FROM Product_Entity pe left Join Entity_Varchar ev
ON pe.entity_id = ev.entity_id
WHERE ev.attribute_id = '73'
If I understand you need, you want every record from Product_Entity, whether or not it has an attribute_id = 73 record on Entity_Varchar. But if there is an attibute_id = 73 record on Entity_Varchar, you want the description from that row also.
First, you need a LEFT OUTER JOIN to get all of the records from Product_Entity, not filtered by the contents of Entity_Varchar.
Then, you need to filter Entity_Varchar. But if you place this filter in the WHERE clause, it causes the join to become an INNER JOIN. (I see error a lot. I call it a "LEFT INNER JOIN". Of course, that's not a real thing.) To overcome this, put the filter in the join logic. Then it's filtered before being joined.
SELECT Product_Entity.sku AS SKU
, Entity_Varchar.value AS Description
FROM Product_Entity
LEFT OUTER JOIN Entity_Varchar ON Entity_Varchar.entity_id = Entity_Varchar.entity_id
AND Entity_Varchar.attribute_id = '73'
Your query is correct you just misspelled table name. Instead of Product_Entity you used Entity_Varchar in both side of on clause.
SELECT Product_Entity.sku AS SKU, Entity_Varchar.value AS Description FROM Product_Entity inner Join Entity_Varchar
ON Product_Entity.entity_id = Entity_Varchar.entity_id
WHERE Entity_Varchar.attribute_id = '73'
I have this inner join query:
select *
from ioa_invoice_line
INNER JOIN ioa_invoice
ON ioa_invoice_line.invo_id = ioa_invoice.id ;
Now, I want to add this condition also in the above inner join that is
where ioa_invoice_line.invo_id =234
Please advise how to add this condition in above query.
As Felix says in his comment you can add it without problems:
select *
from ioa_invoice_line
INNER JOIN ioa_invoice
ON ioa_invoice_line.invo_id = ioa_invoice.id
AND ioa_invoice_line.invo_id = 234
As this is criteria on the first table, you would usually simply add this WHERE clause at the end of your query (before the semicolon of course).
However, you are dealing with an invoice table and its detail table here and the criteria is on the key linking the tables. So for readability, I would swap the tables and name the parent table first and join the child table. That feels more natural:
select *
from ioa_invoice i
join ioa_invoice_line il on il.invo_id = i.id
where i.id = 234;
select * from
ioa_invoice_line il
INNER JOIN ioa_invoice i
ON il.invo_id = i.id
where il.invo_id = 234
This format use as a professional practice
Here is my sql statement in Oracle that I am working with:
SELECT FACILITY.fac_name
, SUM(FEE_LOG.fee_amount) AS TOTAL_FEES
FROM FACILITY
, BOOK_DETAIL
, TRANS_LOG
, FEE_LOG
, TRANS_TYPE
WHERE
FACILITY.fac_id = BOOK_DETAIL.fac_id
AND BOOK_DETAIL.bkdt_id = TRANS_LOG.bkdt_id
AND TRANS_LOG.trans_id = FEE_LOG.trans_id
AND TRANS_LOG.trans_type_id = TRANS_TYPE.trans_type_id
AND
(
TRANS_TYPE.trans_type_desc = 'LOST'
OR TRANS_TYPE.trans_type_desc = 'CHECKIN'
)
GROUP BY FACILITY.fac_name;
It outputs something similar to this:
FACILITY TOTAL_FEES
Facility 1 8.45
Facility 2 4.23
Facility 3 5.23
I have 2 other facilities but they do not have any fees associated with them. I want to show them as 0
So the output would be like:
FACILITY TOTAL_FEES
Facility 1 8.45
Facility 2 4.23
Facility 3 5.23
Facility 4 0
Facility 5 0
ER Diagram
Use LEFT JOIN instead of implicit INNER JOIN for the FEE_LOG table
SELECT FACILITY.fac_name
, SUM(FEE_LOG.fee_amount) AS TOTAL_FEES
FROM FACILITY
JOIN BOOK_DETAIL ON FACILITY.fac_id = BOOK_DETAIL.fac_id
JOIN TRANS_LOG ON BOOK_DETAIL.bkdt_id = TRANS_LOG.bkdt_id
LEFT JOIN FEE_LOG ON TRANS_LOG.trans_id = FEE_LOG.trans_id
JOIN TRANS_TYPE TRANS_LOG.trans_type_id = TRANS_TYPE.trans_type_id
WHERE TRANS_TYPE.trans_type_desc IN ('LOST', 'CHECKIN')
GROUP BY FACILITY.fac_name;
Use outer joins and the on clause:
SELECT FACILITY.fac_name, SUM(nvl(FEE_LOG.fee_amount,0)) AS TOTAL_FEES
FROM FACILITY
left join BOOK_DETAIL
on FACILITY.fac_id = BOOK_DETAIL.fac_id
left join TRANS_LOG
on BOOK_DETAIL.bkdt_id = TRANS_LOG.bkdt_id
left join FEE_LOG
on TRANS_LOG.trans_id = FEE_LOG.trans_id
left join TRANS_TYPE
on TRANS_LOG.trans_type_id = TRANS_TYPE.trans_type_id
and TRANS_TYPE.trans_type_desc in ('LOST', 'CHECKIN')
GROUP BY FACILITY.fac_name;
Note: If these facilities you are referring to, that do not have any fees, have rows on BOOK_DETAIL or TRANS_LOG you can replace the outer join with an inner join (for just those tables). Any table at which point there may or may not be a related record you have to use an outer join.
Try this:
SELECT f.fac_name
, coalesce(SUM(fl.fee_amount),0) AS TOTAL_FEES
FROM FACILITY AS f
INNER JOIN BOOK_DETAIL AS bd
ON bd.fac_id = f.fac_id
INNER JOIN TRANS_LOG AS tl
ON tl.bkdt_id = bd.bkdt_id
LEFT OUTER JOIN FEE_LOG AS fl
ON fl.trans_id = tl.trans_id
INNER JOIN TRANS_TYPE AS tt
ON tt.trans_type_id = tl.trans_type_id
WHERE tt.trans_type_desc in ('LOST' , 'CHECKIN')
GROUP BY f.fac_name;
NB: when you list tables after from with commas between them you're effectively using a cross join.
When you add a condition to your where statement matching a field from one table to a field from another, the join becomes an inner join.
To select all records from one table along with any matches which may or may not exist from another you need an outer join.
There are 3 types:
left outer join where you want all records from the first table listed and any matching records from the second.
right outer join for all records from the second with only matches from the first.
full outer join is all records from both tables, alongside one another where there's a match.
You should always specify the type of join rather than implying it through where clauses / commas, as this makes your intentions clearer and thus your code more readable.
I have a rather complex (well for me) sql query happening and I am having trouble with some concepts.
I have the following sql on a webpage that i am building
SELECT
[dbo].[Enrolment].[_identity], [dbo].[Enrolment].CommencementDate,
[dbo].[Enrolment].CompletionDate, [dbo].[Enrolment].enrolmentDate,
[dbo].[Course].name coursename, [dbo].[Course].Identifier as QUALcode,
[dbo].[Person].givenName, [dbo].[Person].Surname,[dbo].[Employer].name as empname,
[dbo].[Employer].Address1,[dbo].[Employer].Suburb,[dbo].[Employer].Phone,
[dbo].[Employer].PostCode,[dbo].[EnrolmentStatus].name as enrolname,
[dbo].[Student].identifier,[dbo].[Student].person,[dbo].[Contact].person as CONTACTid
FROM
(((([dbo].[Enrolment]
LEFT JOIN
[dbo].[Course] ON [dbo].[Enrolment].course = [dbo].[Course].[_identity])
LEFT JOIN
[dbo].[Employer] ON [dbo].[Enrolment].employer = [dbo].[Employer].[_identity])
LEFT JOIN
[dbo].[EnrolmentStatus] ON [dbo].[Enrolment].status = [dbo].[EnrolmentStatus].[_identity])
LEFT JOIN
[dbo].[Student] ON [dbo].[Enrolment].student = [dbo].[Student].[_identity])
LEFT JOIN
[dbo].[Person] ON [dbo].[Student].person = [dbo].[Person].[_identity]
LEFT JOIN
[dbo].[Contact] ON [dbo].[Employer].[_identity] = [dbo].[Contact].employer
WHERE
(([dbo].[EnrolmentStatus].name) = 'training'
OR
([dbo].[EnrolmentStatus].name) = 'enrolled')
This is working fine but what I would like to do is join to the [dbo].[Person] table again but this time joining from another table so the code I effectively need to patch into the above statement is
LEFT JOIN
[dbo].[Trainer] ON [dbo].[Enrolment].Trainer = [dbo].[Trainer].[_identity])
LEFT JOIN
[dbo].[Person] ON [dbo].[Trainer].person = [dbo].[Person].[_identity]
I then need to be able to get from the person table the name of the student and the name of the trainer, so I need 2 records from the person table for every record from the Enrolment table, the fields I need from the person table are the same for both trainer and student in that I am trying to get the given name and surname for both.
Any help or pointers would be most appreciated.
You have to just use replace your from clause with this. You have to just first use the Trainer table join, then Person table, then use the AND keyword to use multiple mapping with single table
FROM (((([dbo].[Enrolment]
LEFT JOIN [dbo].[Course] ON [dbo].[Enrolment].course = [dbo].[Course].[_identity])
LEFT JOIN [dbo].[Employer] ON [dbo].[Enrolment].employer = [dbo].[Employer].[_identity])
LEFT JOIN [dbo].[EnrolmentStatus] ON [dbo].[Enrolment].status = [dbo].[EnrolmentStatus].[_identity])
LEFT JOIN [dbo].[Student] ON [dbo].[Enrolment].student = [dbo].[Student].[_identity])
LEFT JOIN [dbo].[Trainer] ON [dbo].[Enrolment].Trainer = [dbo].[Trainer].[_identity])
LEFT JOIN [dbo].[Person] ON [dbo].[Student].person = [dbo].[Person].[_identity]
AND [dbo].[Trainer].person = [dbo].[Person].[_identity]
LEFT JOIN [dbo].[Contact] ON [dbo].[Employer].[_identity] = [dbo].[Contact].employer
Use aliasing like this..
LEFT JOIN [dbo].[Trainer] ON [dbo].[Enrolment].Trainer = [dbo].[Trainer].[_identity])
LEFT JOIN [dbo].[Person] AS p ON [dbo].[Trainer].person = p.[_identity]
If I get your question right - what you are trying to do is to join the same table twice in your SQL. You have one table Person which has both student and trainer information and you want to see their details side by side in your result set. So you need to join Person once with Student and another time with Trainer
To do this - you will have to join Person table together. Give your tables an alias like the other answers have suggested. Then your FROM clause can look like this -
FROM (((([dbo].[Enrolment]
LEFT JOIN [dbo].[Course] ON [dbo].[Enrolment].course = [dbo].[Course].[_identity])
LEFT JOIN [dbo].[Employer] ON [dbo].[Enrolment].employer = [dbo].[Employer].[_identity])
LEFT JOIN [dbo].[EnrolmentStatus] ON [dbo].[Enrolment].status = [dbo].[EnrolmentStatus].[_identity])
LEFT JOIN [dbo].[Student] ON [dbo].[Enrolment].student = [dbo].[Student].[_identity])
LEFT JOIN [dbo].[Person] P1 ON [dbo].[Student].person = P1.[_identity]
LEFT JOIN [dbo].[Contact] ON [dbo].[Employer].[_identity] = [dbo].[Contact].employer
LEFT JOIN [dbo].[Trainer] ON [dbo].[Enrolment].Trainer = [dbo].[Trainer].[_identity])
LEFT JOIN [dbo].[Person] P2 ON [dbo].[Trainer].person = P2.[_identity]
....
....
Here P1 and P2 are two aliases for [Person]
I wrote a query. this query sum fields from 2 different table. And grouped by main table id field. But second left outer join is not grouped and giving me different results.
SELECT s.*,
f.firma_adi,
sum(sd.fiyat) AS konak,
sum(ss.fiyat) AS sponsor
FROM fuar_sozlesme1 s
INNER JOIN fuar_firma_2012 f
ON ( s.cari = f.cari )
LEFT OUTER JOIN fuar_sozlesme1_detay sd
ON ( sd.sozlesme_id = s.id )
LEFT OUTER JOIN fuar_sozlesme1_sponsor ss
ON ( ss.sozlesme_id = s.id )
GROUP BY s.id
ORDER BY s.id DESC
I know, it is really complicated but I'm stucking on this issue.
My question is: why second left outer join is not correctly sum of field . If I remove second left outer join or first, everything is normal.
The problem is that you have multiple dimensions on your data, and the number of rows is multiplying beyond what you expect. I would suggest that you run the query for one id, without the group by, to see what rows the join is producing.
One way to fix this is by using correlated subqueries:
select s.*, f.firma_adi,
(select SUM(sd.fiyat)
from fuar_sozlesme1_detay fd
where sd.sozlesme_id = s.id
) as konak,
(select SUM(ss.fiyat)
from fuar_sozlesme1_sponsor ss
where (ss.sozlesme_id = s.id)
) as sponsor
from fuar_sozlesme1 s inner join
fuar_firma_2012 f
on (s.cari = f.cari)
order by s.id DESC
By the way, you appear to by using MySQL (because your query is not parsable in any other dialect). You should tag your questions with the version of the database you are using.