I have following query, but it doesn't return any results for where clauses, even when there is row with that kind of name what is queried. If I remove where clause, then all records in Company table which have OfficeLocation table are returned. What is wrong in my query?
SELECT c.*
FROM [MyDb].[dbo].[Company] AS c
INNER JOIN [MyDb].[dbo].[CompanyOfficeLocation] AS col ON c.Id = col.CompanyId
INNER JOIN [MyDb].[dbo].[OfficeLocation] AS ol ON ol.Id = col.OfficeLocationId
WHERE ol.Name like '%Actual Name In This Table%';
Table structure :
Company
Id
etc ...
CompanyOfficeLocation
CompanyId
OfficeLocationId
OfficeLocation
Id
etc ...
Two things for a record to show up given your query:
The OfficeLocation you specified (given the ol.Name value) must have an Id value that is used by a record in the CompanyOfficeLocation table in its OfficeLocationId.
The CompanyOfficeLocation record that you got in #1 must have a CompanyId that exists in the Company table.
If any of those two criteria are not met, then no records will show up in your query result. The INNER JOIN is essentially an 'AND' clause. If a record could not be related to at least one INNER JOINed table, then that record will not show up at all.
If you want a record to show up despite not having any related records in the joined tables, you may want to consider using OUTER JOINs. A RIGHT JOIN in your case to be exact.
I do not find any mistake however I'd suggest you switch the columns after ON when joining to maintain standards.
Instead of - INNER JOIN [MyDb].[dbo].[OfficeLocation] AS ol ON ol.Id = col.OfficeLocationId
Do - INNER JOIN [MyDb].[dbo].[OfficeLocation] AS ol ON col.OfficeLocationId = ol.Id
Related
I have a query with joins that is not using the index that would be the best match and I am looking for help to correct this.
I have the following query:
select
equipment.name,purchaselines.description,contacts.name,vendors.accountNumber
from purchaselines
left join vendors on vendors.id = purchaselines.vendorId
left join contacts on contacts.id = vendors.contactId
left join equipment on equipment.id = purchaselines.equipmentId
where contacts.id = 12345
The table purchaselines has an index on the column vendorId, which is the proper index to use. When the query is run, I know the value of contacts.id which is joined to vendors.contactId which is joined to purchaselines.vendorId.
What is the proper way to run this query? Currently, no index is used on the table purchaselines.
If you are intending to query a specific contact, I would put THAT first since that is the primary basis. Additionally, you had left-joins to the other tables (vendors, contacts, equipment). So by having a WHERE clause to the CONTACTS table forces the equation to become an INNER JOIN, thus REQUIRING.
That said, I would try to rewrite the query as (also using aliases for simplified readability of longer table names)
select
equipment.name,
purchaselines.description,
contacts.name,
vendors.accountNumber
from
contacts c
join vendors v
on c.id = v.contactid
join purchaselines pl
on v.id = pl.vendorid
join equipment e
on pl.equipmentid = e.id
where
c.id = 12345
Also notice the indentation of the JOINs helps readability (IMO) to see how/where each table gets to the next in a more hierarchical manner. They are all regular inner JOIN context.
So, the customer ID will be the first / fastest, then to vendors by that contact ID which should optimize the join to that. Then, I would expect the purchase lines to have an index on vendorid optimizing that. And finally, the equipment table on ITs PK.
FEEDBACK Basic JOIN clarification.
JOIN is just the explicit statement of how two tables are related. By listing them left-side and right-side and the join condition showing on what relationship is between them is all.
Now, in your data example, each table is subsequently nested under the one prior. It is quite common though that one table may link to multiple other tables. For example an employee. A customer could have an ethnicity ID linking to an ethnicity lookup table, but also, a job position id also linking to a job position lookup table. That might look something like
select
e.name,
eth.ethnicity,
jp.jobPosition
from
employee e
join ethnicitiy eth
on e.ethnicityid = eth.id
join jobPosition jp
on e.jobPositionID = jp.id
Notice here that both ethnicity and jobPosition are at the same hierarchical level to the employee table scenario. If, for example, you wanted to further apply conditions that you only wanted certain types of employees, you can just add your logical additional conditions directly at the location of the join such as
join jobPosition jp
on e.jobPositionID = jp.id
AND jp.jobPosition = 'Manager'
This would get you a list of only those employees who are managers. You do not need to explictily add a WHERE condition if you already include it directly at the JOIN/ON criteria. This helps keeping the table-specific criteria at the join if you ever find yourself needing LEFT JOINs.
I am trying to find the correct join construction to join together the relevant customer info from the Rentals table with the Accidents table. I often run into this issue where my joining fields aren't unique but not sure what else to join on. The accidents table only has about 1500 records but when I join it to pull in more customer data, I get like 35k records. I can do some joins but frequently have joins like this at work and I feel like a dummy because I am not sure how to troubleshoot...
SELECT a.*,
r.market,
r.date_of_birth,
r.is_blocked,
r.rate_type
FROM `accidents` a
LEFT JOIN `rentals` r -- I also tried an INNER JOIN
USING (customer_id) -- Other fields I tried to match on: Full Name
ORDER BY accident_dt DESC
I just started using SQL and I need some help. I have 4 tables in a database. All four are connected with each other. I need to find the amount of unique transactions but can't seem to find it.
Transactions
transaction_id pk
name
Partyinvolved
transaction.id pk
partyinvolved.id
type (buyer, seller)
PartyCompany
partyinvolved.id
Partycompany.id
Companies
PartyCompany.id pk
sector
pk = primary key
The transaction is unique if the conditions are met.
I only need a certain sector out of Companies, this is condition1. Condition2 is a condition inside table Partyinvolved but we first need to execute condition1. I know the conditions but do not know where to put them.
SELECT *
FROM group
INNER JOIN groupB ON groupB.group_id = group.id
INNER JOIN companies ON companies.id = groupB.company_id
WHERE condition1 AND condition2 ;
I want to output the amount of unique transactions with the name.
It is a bit unclear what you are asking as your table definitions look like your hinting at column meanings more than names such as partycompany.id you are probably meaning the column that stores the relationship to PartyCompany column Id......
Anyway, If I follow that logic and I look at your questions about wanting to know where to limit the recordsets during the join. You could do it in Where clause because you are using an Inner Join and it wont mess you your results, but the same would not be true if you were to use an outer join. Plus for optimization it is typically best to add the limiter to the ON condition of the join.
I am also a bit lost as to what exactly you want e.g. a count of transactions or the actual transactions associated with a particular sector for instance. Anyway, either should be able to be derived from a basic query structure like:
SELECT
t.*
FROM
Companies co
INNER JOIN PartyCompancy pco
ON co.PartyCompanyId = pco.PartyCompanyId
INNER JOIN PartyInvolved pinv
ON pco.PartyInvolvedId = pinv.PartyInvolvedId
AND pinv.[type] = 'buyer'
INNER JOIN Transactions t
ON ping.TransactionId = t.TransactionId
WHERE
co.sector = 'some sector'
I have two tables: Company and Contact, with a relationship of one-to-many.
I have another table Track which identifies some of the companies as parent companies to other companies.
I want to write a SQL query that selects the parent companies from Track and the amount of contacts that each parent has.
SELECT Track.ParentId, Count(Contact.companyId)
FROM Track
INNER JOIN Contact
ON Track.ParentId = Contact.companyId
GROUP BY Track.ParentId
however The result holds less records than when I run the following query:
SELECT DISTINCT Track.ParentId
FROM Track
I tried the first query with an added DISTINCT and it returned the same results (less then what it was meant to).
You're performing an INNER JOIN with the Contact table, which means that any rows from the first table (Track in this case) with no matches to the JOINed table will not show up in your results. Try using a LEFT OUTER JOIN instead.
The COUNT with Contact.companyId will only count rows where there is a match (Contact.companyId is not NULL). Since you're counting contacts that's fine as they will count as 0. If you were trying to count some other set of data and tried to do a COUNT on a specific column (rather than COUNT(*)) then any NULL values in that column would not count towards your total, which might or might not be what you want.
I used an INNER JOIN which returns only records that are identical in both tables.
To return all records from Track table, and records that match in the Contact table, I need to use LEFT JOIN.
I have this query which is returning some redundant data. Can somebody please help me to correct this query. I have also attached the table relationship.
SELECT
dbo.supplierOrder.sectionID,
dbo.supplierOrder.supplierID,
dbo.supplierOrder.supplierOrderNo,
dbo.supplierOrder.supplierOrderCreated,
dbo.supplierOrder.supplierOrderConfirmStatus,
dbo.supplierOrderDetails.productID,
dbo.supplierOrderDetails.orderQty,
dbo.supplierOrderReceive.invoiceno,
dbo.supplierOrderReceive.supplierInvoiceno,
dbo.supplierOrderReceive.ID,
dbo.supplierOrderReceiveDetail.qtyArrived
FROM
dbo.supplierOrder
INNER JOIN
dbo.supplierOrderDetails ON (dbo.supplierOrderDetails.supplierOrderID = dbo.supplierOrder.ID)
INNER JOIN
dbo.supplierOrderReceive ON (dbo.supplierOrderReceive.supplierOrderID = dbo.supplierOrder.ID)
INNER JOIN
dbo.supplierOrderReceiveDetail ON (dbo.supplierOrderReceiveDetail.supplierOrderReceiveID = dbo.supplierOrderReceive.ID)
WHERE
dbo.supplierOrder.ID = 1 ;
here is the output that I get
which is not exactly what I was want. the last column qtyArrived should show only its related qty but here as you can see it is repeating for each of the productID
and here is the db tables and relationship
I think the last table should be join using also ProductId not only OrderID :
LEFT JOIN
dbo.supplierOrderReceiveDetail
ON
(dbo.supplierOrderReceiveDetail.supplierOrderReceiveID=dbo.supplierOrderReceive.ID)
AND
(dbo.supplierOrderReceiveDetail.ProductID =dbo.sdbo.supplierOrderDetails.ProductID)