I have table that stores employee job name, it has the following columns:
id; date_from; date_to; emp_id; jobname_id; grade;
Each emp_id can have many consecutive records with the same jobname_id due to many grade changes.
How can I select previous different jobname_id omitting those that are the same like the most current one?
This solution uses the FIRST_VALUE() analytic function to identify each employee's current job. It then filters for all the jobs which dfon't match that one:
select distinct id
, jobname_id
from ( select id
, jobname_id
, first_value(jobname_id) over (partition by id
order by from_date desc) as current_job
from employee
where emp_id = 1234 )
where jobname_id != current_job
order by id, jobname_id
/
Will this work for your issue:
SELECT DISTINCT
e1.emp_id,
e1.jobname_id
FROM employee e1
WHERE NOT EXISTS
(SELECT 1
FROM employee e2
WHERE e1.emp_id = e2.emp_id
AND SYSDATE BETWEEN e2.date_from
AND NVL(e2.date_to, SYSDATE + 1));
(This asumes your table is named "employee" and emp_id is the PK value).
It selects unique emp_id, jobname_id values where the emp_id, jobname_id values are not current.
EDIT: I agree with Chin Boon that fundamentally this is a design issue and perhaps that should be addressed rather than working around the problem.
Related
These were the two questions asked to me during an interview but only condition is to use rank/dense_rank.
Find second highest salary in each department using rank/dense_rank in
hive.
When there are sufficient records in each department.
When there is only 1 record in few departments.
Guide me if this is even valid or not.
If yes then what should be the queries for the same.
If you need to select all second salary employees then use
dense_rank() over(partition by department order by salary desc) = 2 filter. It will return all employees with second salary.
When there is only 1 record in the department (no second salary exists, one employee in the department), it will be ranked 1 and you will get no records for that department filtering by dense_rank = 2.
If you need to select only one record (not all employees) with second salary then row_number() over(partition by department order by salary desc) = 2 will work, but it will pick one random employee with second salary if there are many employees with second salary. Only one record will be marked with row_number = 2.
Try this:
WITH RESULT AS
(
SELECT salary, DENSE_RANK() OVER (PARTITION BY department ORDER BY salary DESC) AS SecondHighest FROM Employee
)
SELECT IFNULL(( SELECT salary FROM RESULT WHERE SecondHighest = 2 ORDER BY salary) , NULL) as SecondHighestSalary
I have to find record from the hive table where Id, der__timestamp, header__change_seq should be unique but in table (Id, der__timestamp, header__change_seq) can duplicate so in this case i have to fetch only one record if records are getting duplicate .
select b.*
from (SELECT ID, max(COALESCE(header__timestamp))
max_modified,MAX(CAST(header__change_seq AS DECIMAL(38,0))) max_sequence
FROM table_name group by ID) a
join table_name b on (a.id=b.id and
a.max_modified=b.header__timestamp and
a.max_sequence=b.header__change_seq)
So the total number of distinct id is count-->244441250
but through above query i am getting count-->244442548
due to some duplicate records but i have to find only distinct id where (header__change_seq and header__timestamp) should max .
#Rahul; please try this one. It makes use of row_number() so in case of duplicate id, header_timestamp and hearder_change_seq, it will select only one record. Hope it helps.
select *
from (
select *,
row_number() over ( partition by id order by header__timestamp desc, header__change_seq desc) as rnk
from table_name) t
where t.rnk = 1;
I have a table user_audit_records_tbl which has multiple rows for a single user ,Every time user logs in one entry is made into this table so i want a select query which will fetch a latest single record for each user, I have a query which uses IN clause.
Table Name : user_audit_records_tbl
Record_id Number Primary Key,
user_id varchar Primary Key ,
user_ip varchar,
.
.
etc
Current query i am using is
select * from user_audit_records_tbl where record_id in (select
max(record_id) from user_audit_records_tbl
group by user_id);
but was just wondering if anybody has better solution for this since this table has huge volumns.
You can use the first/last function
select max(Record_id) as Record_id,
user_id,
max(user_ip) keep (dense_rank last order by record_id) as user_ip,
...
from user_audit_records_tbl
group by user_id
No sure if it will be more efficient.
EDIT : As above query is less efficient, may be you could try an exist clause
select *
from user_audit_records_tbl A
where exists ( select 1
from user_audit_records_tbl B
where A.user_id = B.user_id
group by B.user_id
having max(B.record_id) = A.record_id
)
But maybe, you should look on the index side instead of the query side.
select *
from ( select row_number() over ( partition by user_id order by record_id desc) row_nr,
a.*
from user_audit_records_tbl a
)
where row_nr = 1
;
i want to delete the last recent record from my table.
Code to select the last record:
SELECT * FROM
( select ID, NAME,
createdon
from Person where age= 30
order by createdon DESC)
WHERE ROWNUM <= 1;
i tried this to delete the last records:
DELETE * FROM
( select ID, NAME,
createdon
from Person where age= 30
order by createdon DESC)
WHERE ROWNUM <= 1;
It 's not working.
ERROR: "invalid table name"
Any help please, Thank you
As OracleUser said, you can't delete from an in-line view. You can use your original inner query to delete based on all three columns it selects, assuming they will uniquely identify a single row:
delete from person
where (id, name, createdon) = (
select * from (
select id, name, createdon
from person
where age = 30
order by createdon desc
)
where rownum <= 1
);
SQL Fiddle.
If ID is a primary or unique key you can do this instead:
delete from person
where id =
(
select id
from (
select id, row_number() over (order by createdon desc) as rn
from person where age = 30
)
where rn = 1
);
If it is not then you can use rowid instead, replacing both references to id in the statement.
The innermost query is basically the same as the inner query in your select, but I'm using the row_number analytic function to assign the equivalent of rownum. The next layer out filters out everything except the most recent, based on the row_number calculation.
You can use rank() instead but could get two record with exactly the same times, and would need to decide whether both should be deleted, or if you should have some additional way to break the tie - e.g. order by createdon desc, id desc. As I've shown it here, row_number() also breaks the tie arbitrarily but can have the explicitly extra ordering to control that, as would rownum. And there's also dense_rank().
SQL Fiddle.
This is a bit simpler but would also delete multiple rows, if you had more than one with the same createdon value:
delete from person
where createdon =
(
select max(createdon)
from person
where age = 30
);
Sorry for the Confusing title.I myself did not understand it when i read it second time.
So here is the details description.
I have a table say "Awards" which have following Column:
Name,
Amount,
Employee
and Another table "Employee" which have following column:
Emp_Id,
Emp_Name
and in employee column of "Awards" table i have value "01,20" which are actually the Employee ID referenced to "Employee" table.
So is there any way i can get Employee Name in select "Awards" query?
Here is one method:
select a.*, e.EmpName
from Awards a join
Employees e
on ','||a.employee||',' like '%,'||e.emp_id||',%';
This will return the employee names on separate lines. If you want them in a list, then you would need to concatenate them together (and the best function for doing that depends on your version of Oracle).
By the way, this is a very bad data structure, You should have an association table AwardEmployee that has one row for each row and each employee.
Given below is the query to get comma seperated employee ids in form of rows which I put in subquery to get their name. Please edit as per your ewquirements.
Select Ename from employee where employee_id in (
SELECT trim(x.column_value.extract('e/text()')) COLUMNS
from awards t, table (xmlsequence(xmltype('<e><e>' || replace(Employee,':','</e><e>')||
'</e></e>').extract('e/e'))) x )
I have changed the Database (added one more table). and already started changing the CODE, as for the said report i have used following
WITH t AS
(
Select emp_name from employee where emp_id in (
select regexp_substr(Employee ,'[^,]+', 1, level) from awards
connect by regexp_substr((select Employee from awards ), '[^,]+', 1, level) is
not null)
)
SELECT LTRIM(SYS_CONNECT_BY_PATH(emp_name, ','),',') emp_name
FROM ( SELECT emp_name,
ROW_NUMBER() OVER (ORDER BY emp_name) FILA
FROM t )
WHERE CONNECT_BY_ISLEAF = 1
START WITH FILA = 1
CONNECT BY PRIOR FILA = FILA - 1
Which is temporary and i understand very less of it.
Thanks for you help and suggestion.