Kind of hard to explain, so I'll map it out. Given these four tables: houses, landlord_houses, company and tenant, I need to find all the houses that have signed up in the last 14 days and get some information about them.
Previously I've done this with a very simple select query from the houses table. But now I need to get the letting agent of the house to display on a report. The problem is, the letting agent can be in any one of 3 locations: in the company table, the houses table or in the tenant table. I've come up with this query so far:
select distinct h.id as id,
h.address1 as address1,
h.town as town,
h.postcode as postcode,
h.valid_from as valid_from,
h.valid_to as valid_to,
(CASE WHEN c.name IS NOT NULL THEN c.name || ' (MS)'
WHEN h.letting_agent IS NOT NULL THEN h.letting_agent
WHEN t.id IS NOT NULL THEN t.letting_agent
ELSE 'Unknown (Not set yet)' END) AS agent
from houses h
left join landlord_houses lh on lh.house_id = h.id
left join company c on c.id = lh.company_id
left join tenant t on t.house_id = h.id
where h.deleted IS FALSE
and h.archived IS FALSE
and h.sign_up_complete IS TRUE
and h.completed > NOW() - '14 days'::INTERVAL
order by h.id
This kind of works, however I'm getting results back that have an empty agent field even though it's meant to say "Unknown (Not set yet)". I'm also getting duplicate houses returned even though I've used distinct h.id. I think this is because there are multiple letting agents for these houses in the company, houses and tenant tables.
What needs to be changed in the query to get this to work?
Thank you.
That case statement looks a little wonky. You may be returning multiple values. Try this:
COALESCE(c.name, h.letting_agent, t.letting_agent, 'Unknown (Not set yet)') as Agent
This checks c.name. If it is null, move to the next argument and do the same.
Everything else in the query looks fine and this does work in postgresql.
Related
I've got a task to work with 4 different tables. I think I've got the "logic" correct, but I think I'm failing on joining the various separately working things together.
The Case somehow returns two rows when the comparison is true; if it isn;t, it displays (correctly) just one. Works fine without joins.
The count subquery works when by itself, but when I'm trying to tie it together, it displays anything from showing the same number everywhere or displaying far too large numbers (likely multiples or multiples).
Select Distinct RPD_PERSONS.PERSON_ID "id",
RPD_PERSONS.SURN_TXT ||' '|| RPD_PERSONS.NAME_TXT "Name",
Case ADD_ROLE_PERS.ROLE_CODE When 'Manager'
Then 'yes'
Else 'no'
End "Manager",
(
Select Count(LDD_CERTS.Cert_ID)
From LDD_CERTS
Join LDD_PERS_CERTS
On LDD_PERS_CERTS.CERT_ID = LDD_CERTS.CERT_ID
Where MONTHS_BETWEEN(LDD_CERTS.VALID_TO,SYSDATE)>0
And LDD_PERS_CERTS.CERT_CHANGE_TYPE>=0
) "no. of certificates"
From RPD_PERSONS
Join ADD_ROLE_PERS
On ADD_ROLE_PERS.Person_ID = RPD_PERSONS.Person_ID
Where RPD_PERSONS.Partic_ID = 1
Group By RPD_PERSONS.PERSON_ID, RPD_PERSONS.SURN_TXT ||' '|| RPD_PERSONS.NAME_TXT, ADD_ROLE_PERS.ROLE_CODE
Order By RPD_PERSONS.Person_ID;
This is the subquery that, by itself, seems to work perfectly.
Select LDD_PERS_CERTS.PERSON_UID,Count(LDD_CERTS.Cert_ID)
From LDD_CERTS
Join LDD_PERS_CERTS
ON LDD_PERS_CERTS.CERT_ID = LDD_CERTS.CERT_ID
Where MONTHS_BETWEEN(LDD_CERTS.VALID_TO,SYSDATE)>0
AND LDD_PERS_CERTS.CERT_CHANGE_TYPE>=0
Group By LDD_PERS_CERTS.PERSON_UID
order by LDD_PERS_CERTS.PERSON_UID;
You have a lot of things going on although a short query to get it, but let me try to summarize what I THINK you are trying to get.
You want a list of distinct people within the company with a count of how many ACTIVE certs (not expired) per person. From that, you also want to know if they are in a management position or not (via roles).
Q: For a person who may be a manager, but also an under-manager to a higher-up, do you want to see that person in both roles as typical business structures could have multiple layers of management, OR... Do you only care to see a person once, and if they are a manager OR some other level. What if a person has 3 or more roles, do you want to see them every instance? If your PRIMARY care is Manager Yes or No, the query gets even more simplified.
Now, your query of counts for valid certs. The MONTHS_BETWEEN() function appears to be you are running in Oracle. Based on the two parameters of the Valid_To date compared to sysdate is an indication that the valid to is always intended to be in the future (ie: Still has an active cert). If this is the case, you will not be able to optimize query as function calling is not Sargable
Instead, you should only have to do where Valid_To > SysDate, in other words, only those that have not yet expired. You MIGHT even be better served by pre-aggregating all counts of still active cert counts per Cert ID, then joining to the person certs table since the person cert check is for all where the cert_change_type >= 0 which could imply ALL. What condition would a Cert_Change_Type be anything less than zero, and if never, that where clause is pointless.
Next, your SELECT DISTINCT query needs a bit of adjustments. Your column-based select has no context to the outer person ID and is just aggregating the total certs. There is no correlation to the person ID to the certs being counted for. I can only GUESS that there is some relationship such as
RPD_Persons.Person_id = LDD_Pers_Certs.Person_UID
Having stated all that, I would have the following table/indexes
table index
LDD_PERS_CERTS ( CERT_CHANGE_TYPE, PERSON_UID, CERT_ID )
LDD_CERTS ( valid_to, cert_id )
RPD_PERSONS ( partic_id, person_id, surn_txt, name_txt )
ADD_ROLE_PERS ( person_id, role_code )
I would try something like
Select
lpc.PERSON_UID,
ValCerts.CertCount
From
( select
Cert_id,
count(*) CertCounts
from
LDD_CERTS
where
Valid_To > sysDate
group by
Cert_id ) ValCerts
JOIN LDD_PERS_CERTS lpc
on ValCerts.Cert_id = lpc.cert_id
Where
lpc.CERT_CHANGE_TYPE >= 0
Now, if you only care if a given person is a manager or not, I would pre-query that only as you were not actually returning a person's SPECIFIC ROLE, just the fact they were a manager or not. My final query might look like'
select
p.PERSON_ID id,
max( p.SURN_TXT || ' ' || p.NAME_TXT ) Name,
max( Case when arp.Person_id IS NULL
then 'no' else 'yes' end ) Manager,
max( coalesce( certs.CertCount, 0 )) ActiveCertsForUser
from
RPD_PERSONS p
LEFT Join ADD_ROLE_PERS arp
On p.Person_ID = arp.Person_ID
AND arp.role_code = 'Manager'
LEFT JOIN
( Select
lpc.PERSON_UID,
ValCerts.CertCount
From
( select
Cert_id,
count(*) CertCounts
from
LDD_CERTS
where
Valid_To > sysDate
group by
Cert_id ) ValCerts
JOIN LDD_PERS_CERTS lpc
on ValCerts.Cert_id = lpc.cert_id
AND lpc.CERT_CHANGE_TYPE >= 0 )
) Certs
on p.Person_id = Certs.Person_uid
Where
p.Partic_ID = 1
GROUP BY
p.PERSON_ID
Now, if the p.partic_id = 1 represents only 1 person, then that wont make as much sense to query all people with a given certificate status, etc. But if Partic_id = 1 represents a group of people such as within a given association / division of a company, then it should be fine.
Any questions, let me know and I can revise / update answer
CASE issue: there can be, presumably, be multiple records in ADD_ROLE_PERS for each person. If a person can have two or more roles running concurrently then you need to decide what the business logic is that you need to use to handle this. If a person can only have one active role at a time presumably there is a "active/disabled" column or effective date columns you should be using to identify the active record (or, potentially, there is a data issue).
The subquery should return the same value for every single row in your resultset, as it is completely isolated/standalone from your main query. If you want it to produce counts that are relevant to each row then you will need to connect it to the tables in the main table (look up correlated subqueries if you don't know how to so this)
I'll try to explain my problem:
I need to find the most efficient way to join two table on 4 columns, but data is really crappy so there could be cases where I can join only on 3 or 2 columns because the fourth and/or third were stored badly (with spaces, zeros, dashes,...)
I should try to achieve something like this:
select * from table a
join table b
on a.key1=b.key1
and a.key2=b.key2
or a.key3=b.key3
or a.key4=b.key4```
I already performed some data quality but the number of records is really high (table a is 300k records and table b is about 25M records).
I know that the example I provided is not efficient and it would be better making separate joins and then "union" them, but I'm asking you if there could be some better way to do it.
Thanks in advance
You haven't explained your problem very well, so let's create an example:
There is a table of clients and a table of orders. Both are not related via keys, because both are imported from different systems. Your task is now to find the client per order.
Both tables contain the client's last name, first name, city, and a client number. However, these columns are optional in the order table (but either last name or client number are always given). And sometimes a first name or city may be abbreviated or misspelled (e.g. J./James, NY/New York, Cris/Chris).
So, if the order contains a client number, we have a match and are done. Otherwise the last name must match. In the latter case we look at first name and city, too. Do both match? Only one? Neither?
We use RANK to rank the clients per order and pick the best matches. Some orders will end up with exactly one match, others will have ties and we must examine the data manually then (the worst case being no client number and no last name match because of a misspelled name).
select *
from
(
select
o.*,
c.*,
rank() over
(
partition by o.order_number
order by
case
when c.client_number = o.client_number then 1
when c.last_name = o.last_name and c.first_name = o.first_name and c.city = o.city then 2
when c.last_name = o.last_name and (c.first_name = o.first_name or c.city = o.city) then 3
when c.last_name = o.last_name then 4
else 5
end
) as rnk
from orders o
left join clients c on c.client_number = o.client_number or c.last_name = o.last_name
) ranked
where rnk = 1
order by order_number;
I hope this gets you an idea how to write such a query and you will be able to adapt this concept to your case.
This query works. I´m trying to find the most recent date of Document input in our system.
The query below brings the date and supplier number, and it's working perfectly.
SELECT SUPPLIERNUMBER, MAX(DATEOFINPUT)
FROM TABLE A
WHERE COUNTRY IN ('661')
AND COMPANY IN ('01','40')
GROUP BY SUPPLIERNUMBER
Now, that information is great by itself, but I will also need additional information that it´s in another table B (the one that holds the information from the Suppliers, like Name, Short Name, Bank Data, etc)
SELECT B.COUNTRY , B.COMPANY ,B.SUPPLIERNUMBER,
B.SUPPLIERNAME, A.DATEOFINPUT
FROM A
INNER B
ON A.COUNTRY =B.COUNTRY
AND A.COMPANY =B.COMPANY
Here is where I don't know how to mix the 2 queries together. I understand I need from the first Query 2 columns of information: SupplierNumber and DateofInput.
With this information I have to join with the other table to get the Supplier information.
I'm not sure how to do this. I thought I had to do a subquery with MAX(DateofInput) but that way it will only bring 1 record of several with the same date, but no way to also bring the SupplierNumber.
Could you folk help me please?
This is for DB2, maybe some SQL syntax won´t work, not sure.
I only have user privileges, not admin access.
Incorporate the data fields from SUPPLIER table (B) into the SELECT and include them in the GROUP BY clause:
SELECT A.SUPPLIERNUMBER,
B.SUPPLIERNAME, B.COUNTRY, B.COMPANY, MAX(DATEOFINPUT) AS MAXDATE
FROM TABLE A
INNER JOIN SUPPLIER B
ON A.SUPPLIERNUMBER = B.SUPPLIERNUMBER
WHERE A.COUNTRY IN ('661')
AND A.COMPANY IN ('01','40')
GROUP BY A.SUPPLIERNUMBER, B.SUPPLIERNAME, B.COUNTRY, B.COMPANY
I'm having an issue creating a query. Here are the specifics.
There are 2 tables company_career and company_people.
People contains person information (Name, Address, etc) and Career contains historical career information (job_title, department, etc.)
People is linked to Career by job_ref_id.
Direct_Report_id lies in the career table and contains a unique id that correlates to job_ref_id.
Example: job_ref_id = '1' results in direct_report_id ='A'. I then use the value produced from direct-report_id (i.e., 'A') and query the job_ref_id = 'A' and this produces the employee name. Since it produces the employee name (which is actually the manager) I need to know how I would query this to present this as the manager name.
I think I know what you are looking for, you just need to use joins and aliases. For example:
SELECT
cp.name AS [EmployeeName],
cp.address AS [EmployeeAddress],
cc.job_title AS [EmployeeTitle],
cc.department AS [EmployeeDept],
m.name AS [ManagerName]
FROM company_people cp
LEFT JOIN company_career cc ON cc.job_ref_id = cp.job_ref_id
LEFT JOIN company_people m ON m.job_ref_id = cc.direct_report_id
I am pulling reports for my company and am needing to pull a specific report that I am having trouble with. We are using SQL Server 2012 and I am pulling the SQL reports.
What I need is to pull a simple report:
Group Name, List of Members in the group; Supervisor of the group.
However, the problem is that the supervisor as well as the members and the group name all come from one table in order to get the relevant information. Currently here is my SQL code below:
Use DATABASE
go
-- This is the select portion deciding the columns needed.
select
C.group_name
,C2.first_name
,C2.last_name
-- These are the tables that the query is pulling from.
FROM db..groups AS G
LEFT OUTER JOIN db..contact AS C
ON G.group_id=C.contact_id
INNER JOIN db..contact AS C2
ON G.member=C2.contact_id
go
This pulls the first portion:
The group name, then the first name of a member in that group, and then the last name of a member in that group.
However, I am having trouble getting the supervisor portion. This portion uses the table db.contact under the column supervisor_id as a foreign key. The supervisor_id uses the same unique id as the normal contact_id, but in the same table. Some contact_ids have supervisor_id's that are other contact_id's from the same table, hence the foreign key.
How can I make it so I can get the contact_id that is equal to the supervisor_id of the contact_id that is equal to the group_id?
Taking a quick stab at this while we wait for details
You know you need groups and I'm assuming you don't care about Groups that have no members. Thus Groups INNER JOINed to Contact. This generates your direct group membership. To get the supervisor, you then need to factor in the Supervisor on the specific Contact row.
You might not have a boss, or your boss might be yourself. It's always interesting to see how various HR systems record this. In my example, I'm assuming the head reports to no one instead of themselves.
SELECT
G.group_name
, C.first_name
, C.last_name
-- this may produce nulls depending on outer vs inner join below
, CS.first_name AS supervisor_first_name
, CS.last_name AS supervisor_last_name
FROM
dbo.Groups AS G
INNER JOIN
dbo.Contact AS C
ON C.contact_id = G.member
LEFT OUTER JOIN
dbo.Contact AS CS
ON CS.contact_id = C.supervisor_id;
Depending on how exactly you wanted that data reported, there are various tricks we could use to report that data. In particular, GROUPING SETS might come in handy.
SQLFiddle