This is an oracle system. I have a client table (one) and an account table (many). Frankly, I really just want to query the client table but due to poor design, there is a data element that I need for the client table that is only present on the account table - it will be the same value for all accounts for that client so I really just need to return one account row but I'm having problems accomplishing this. Here is the query I tried:
Select
c.client_num,
c.client_name,
a.agency_value
from client c
inner join account a on c.client_num = a.client_num
where a.account_num in (select a2.account_num from account a2 where rownum = 1)
You need to explicitly designate how to pick one record out of many. Here's one method - use MAX
Select
c.client_num,
c.client_name,
(SELECT
MAX(a.agency_value) agency_value
FROM account a
where c.client_num = a.client_num
-- not sure if this line is required - if not please remove
and a.account_num in (select a2.account_num from account a2 where rownum = 1)
) agency_value
from client c
Keep in mind that by implementing this you are "cementing" your bad table design.
Are you absolutely certain that there is only ever one agency_value? use query to find any clients that have more than one agency:
SELECT
a.client_num,
COUNT(DISTINCT a.agency_value) CountOfAgencyValues,
MAX(a.agency_value) max_agency_value,
MIN(a.agency_value) max_agency_value
FROM account a
GROUP BY a.client_num
HAVING COUNT(DISTINCT a.agency_value) > 1
With your input and doing some playing around on my own, here is the code that ultimately addressed my need:
select
c. client_num,
(select a.agency_value
from account a
where a.client_num = c.client_num
and rownum = 1)
from client c
Related
I have a column that is like this:
Client ID
Service Name
123456
housing
122458
transportation
125837
education
125837
transportation
173947
Childcare
I am trying to extract data from an Oracle database for all clients who have accessed education and transportation services only. Could anyone please help me write my query?
I have created a Where statement in my query that goes like this:
where ch.service_name IN ('education', 'transportation)
however, this query gives me all clients who have accessed education and or transportation when in fact, I only want data for clients who have accessed both education and or transportation.
thank you
Seems you need a HAVING Clause along with GROUP BY after restricting to only those two service_name such as
SELECT ClientID
FROM t
WHERE service_name IN ('education', 'transportation')
GROUP BY ClientID
HAVING COUNT(DISTINCT service_name) = 2
EDIT(depending on the comment) : One option would be converting the query into the one which contains a COUNT() analytic function such as
WITH t2 AS
(
SELECT t.*, COUNT(DISTINCT service_name) OVER (PARTITION BY ClientID) AS cnt
FROM t
WHERE service_name IN ('education', 'transportation')
)
SELECT *
FROM <the_other_table>
LEFT JOIN t2
WHERE cnt = 2
in order to combine with your current query as desired.
SELECT COALESCE(clnt.ename,clientid) NAME, sum(turnover)
FROM A
LEFT JOIN (SELECT DISTINCT csid,code,CP.ename
FROM Senna
LEFT JOIN (SELECT DISTINCT csid,ename FROM C1) CP ON Senna.csid=CP.csid) clnt ON clientid = clnt.CODE
GROUP BY COALESCE(clnt.ename,clientid)
The above query is taking a lot of time to run and the reason for that is that the Senna and the CP tables are reference tables. I am trying to work a way to the improve the performance so that select clause for code field in the senna table is only picked for the clientid which are contained in the table A. The left join between Senna and the CP table is the reason for the issue of slowness but if somehow I can get the Senna table to fetch records based on only the clientid from A that will improve the performance massively.
Is there a way that the clientids can be included in the where clause of the senna table so that when the join is being done with the cp table, the final join of clientid = clnt.CODE is done on a smaller data set. Essentially, there are a number of records in the senna table which can be filtered out in order to improve performance. The ultimate goal is to pull the ename.
Bear in mind there would be 100s of clientid in table A as well.
Please any help would be appreciated.
I don't know that I understand what you need as an output. Please see whether the below Oracle query helps. If not, please explain your use-case more (say you want to list all the records from table A that matches records with table C1 etc or something similar to it for better understanding)
SELECT
COALESCE(clnt.ename, clientid) NAME,
sum(turnover)
FROM
A
LEFT JOIN (
SELECT
DISTINCT senna.csid,
senna.code,
CP.ename
FROM
Senna senna
join C1 CP on senna.csid = CP.csid
) clnt ON clientid = clnt.CODE
GROUP BY
COALESCE(clnt.ename, clientid);
Using Oracle PL/SQL is there a simple equivalent of the following set of T-SQL statements? It seems that everything I am finding is either hopelessly outdated or populates a table data type with no explanation on how to use the result other than writing values to stdout.
declare #tempSites table (siteid int)
insert into #tempSites select siteid from site where state = 'TX'
if 10 > (select COUNT(*) from #tempSites)
begin
insert into #tempSites select siteid from site where state = 'OK'
end
select * from #tempSites ts inner join site on site.siteId = ts.siteId
As #AlexPoole points out in his comment, this is a fairly contrived example.
What I am attempting to do is get all sites that meet a certain set of criteria, and if there are not enough matches, then I am looking to use a different set of criteria.
Oracle doesn't have local temporary tables, and global temporary tables don't look appropriate here.
You could use a common table expression (subquery factoring):
with tempSites (siteId) as (
select siteid
from site
where state = 'TX'
union all
select siteid
from site
where state = 'OK'
and (select count(*) from site where state = 'TX') < 10
)
select s.*
from tempSites ts
join site s on s.siteid = ts.siteid;
That isn't quite the same thing, but gets all the TX IDs, and only includes the OK ones if the count of TX ones - which has to be repeated - is less than 10. The CTE is then joined back to the original table, which all seems a bit wasteful; you're hitting the same table three times.
You could use a subquery directly in a filter instead:
select *
from site
where state = 'TX'
or (state = 'OK'
and (select count(*) from site where state = 'TX') < 10);
but again the TX sites have to be retrieved (or at least counted) a second time.
You can do this with a single hit of the table using an inline view (or CTE if you prefer) with an analytic count - which add the count of TX rows to the columns in the actual table, so you'd probably want to exclude that dummy column from the final result set (but using * is bad practice anyway):
select * -- but list columns, excluding tx_count
from (
select s.*,
count(case when state = 'TX' then state end) over (partition by null) as tx_count
from site s
where s.state in ('TX', 'OK')
)
where state = 'TX'
or (state = 'OK' and tx_count < 10);
From your description of your research it sounds like what you've been looking at involved PL/SQL code populating a collection, which you could still do, but it's probably overkill unless your real situation is much more complicated.
looking for solution on my sql query error.I'm trying to create second cascading Input Control in JaspersoftServer. The first Input Control works fine, however when I try to create a second cascade IC it returns with the error. I have 3 tables (user, client, user_client), many to many, so 1 linked table (user_client) between them.The 1st Input Control (client) - works well, end user will select the client, the client can have many users, so cascade is the key. Also, as the output, I would like to get not the user_id, but user's firstname and the lastname as one column field. And here is where i'm stuck. I'm pretty sure it is simple syntaxis error, but spent a good couple of hours to figure out what is wrong with it. Is anyone can have a look at it please and indicate where is the problem in my query ?! So far I've done:
select distinct
u.user_id,(
SELECT CONCAT(first_name, surname) AS user_name from tbl_user ),
c.client_id
FROM tbl_user u
left join tbl_user_client uc
on uc.user_id = u.user_id
left join tbl_client c
on c.client_id = uc.client_id
where c.client_id = uc.client_id
order by c.client_id
Thank you in advance.
P.S. JasperServer + Oracle 11g
You're doing an uncorrelated subquery to get the first/last name from the user table. There is no relationship between that subquery:
SELECT CONCAT(first_name, surname) AS user_name from tbl_user
... and the user ID in the main query, so the subquery will attempt to return every first/last name for all users, for every row your joins find.
You don't need to do a subquery at all as you already have the tbl_user information available:
select u.user_id,
CONCAT(u.first_name, u.surname) AS user_name
c.client_id
FROM tbl_user u
left join tbl_user_client uc
on uc.user_id = u.user_id
left join tbl_client c
on c.client_id = uc.client_id
where c.client_id = uc.client_id
order by c.client_id
If you want to put a space between the first and last name you'll either need nested concat() calls, since that function only takes two arguments:
select u.user_id,
CONCAT(u.first_name, CONCAT(' ', u.surname)) AS user_name
...
... or perhaps more readably use the concatenation operator instead:
select u.user_id,
u.first_name ||' '|| u.surname AS user_name
...
If the first control has selected a client and this query is supposed to find the users related to that client, you're joining the tables the wrong way round, aren't you? And you aren't filtering on the selected client - but no idea how that's actually implemented in Jasper. Maybe you do want the entire list and will filter it on the Jasper side.
I need help! For example, there are four tables: cars, users, departments and join_user_department. Last table used for M: N relation between tables user and department because some users have limited access. I need to get the number of cars in departments where user have access. The table “cars” has a column department_id. If the table join_user_department doesn’t have any record by user_id this means that he have access to all departments and select query must be without any condition. I need do something like this:
declare
DEP_NUM number;--count of departments where user have access
CARS_COUNT number;--count of cars
BEGIN
SELECT COUNT (*) into DEP_NUM from join_user_departments where user_id=?;
SELECT COUNT(*) into CARS_COUNT FROM cars where
IF(num!=0)—it meant that user access is limited
THEN department_id IN (select dep_id from join_user_departments where user_id=?);
A user either has access to all cars (I'm assuming all cars are tied to a department, and the user has access to all departments) or the user has limited access. You can use a UNION ALL to bring these two groups together, and group by user to do a final count. I've cross joined the users with unlimited access to the cars table to associate them with all cars:
(UPDATED to also count the departments)
select user_id,
count(distinct department_id) as dept_count,
count(distinct car_id) as car_count,
from (
select ud.user_id, ud.department_id, c.car_id
from user_departments ud
join cars c on c.department_id = ud.department_id
UNION ALL
select u.user_id, v.department_id, v.car_id
from user u
cross join (
select d.department_id, c.car_id
from department d
join cars c on c.department_id = d.department_id
) v
where not exists (
select 1 from user_departments ud
where ud.user_id = u.user_id
)
)
group by user_id
A UNION ALL is more efficient that a UNION; a UNION looks for records that fall into both groups and throws out duplicates. Since each user falls into one bucket or another, UNION ALL should do the trick (doing a distinct count in the outer query also rules out duplicates).
"If the table join_user_department doesn’t have any record by user_id
this means that he have access to all departments"
This seems like very bad practice. Essentially you are using the absence of records to simulate the presence of records. Very messy. What happens if there is a User who has no access to a Car from any Department? Perhaps the current business logic doesn't allow this, but you have a "data model" which won't allow to implement such a scenario without changing your application's logic.