I was trying to arrange seat for an examination from the below dataset.
and the output dataset would be like the below(alternate department student one after another)
I am unable to get the desire output. Please help me on that. I am using the Oracle 11g express edition.
http://sqlfiddle.com/#!4/510071/1
Using ROW_NUMBER analytic function, create sort order for each department; then select values sorted by that number.
For example:
SQL> with test (roll_no, name, department) as
2 (select 1, 'anik', 'cse' from dual union all
3 select 2, 'sudipto', 'cse' from dual union all
4 select 3, 'injamam', 'cse' from dual union all
5 select 8, 'sajukta', 'ece' from dual union all
6 select 9, 'gourab', 'ece' from dual union all
7 select 10, 'soumenn', 'ece' from dual),
8 inter as
9 (select roll_no, name, department,
10 row_number() over (partition by department order by roll_no) rn
11 from test
12 )
13 select roll_no, name, department
14 from inter
15 order by rn, department;
ROLL_NO NAME DEP
---------- ------- ---
1 anik cse
8 sajukta ece
2 sudipto cse
9 gourab ece
3 injamam cse
10 soumenn ece
6 rows selected.
SQL>
You seem to want them interleaved. If so, use row_number() in the order by:
select s.*
from student s
order by row_number() over (partition by "department" order by "roll_no"),
"department";
Here is the SQL Fiddle.
Note: Don't wrap column names in double quotes. That means that the case of the identifier matters -- and just makes queries harder to write.
Related
I have a table where I have two columns i.e customer, project_id.. My requirement is to find for each customer what is the first project_id, and correspondingly name it like 'General Project' and if there are more than one projects for customer found then name the next project as concat('PROJECT', '-', project_id). In the picture below you can see the 4th column data is the desired result for my requirement, but I am not sure how to find this out? thanks in advance
You can use row_number() and string manipulation:
select t.*,
(case when row_number() over (partition by customer order by row_number()) = 1
then 'General Project'
else replace('Project-[n]', '[n]', project_id)
end) as project_name
from t;
This happens to work in both Oracle and SQL Server.
Here's one option (which works in Oracle; can't tell about SQL Server). Sample data (you already have & don't type it is in lines #1 - 13. Query you might be interested in begins at line #15.
SQL> with
2 test (row_num, customer, project_Id) as
3 -- sample data
4 (select 1, 115432, 1 from dual union all
5 select 2, 115432, 2 from dual union all
6 select 3, 115432, 3 from dual union all
7 --
8 select 4, 116500, 1 from dual union all
9 select 5, 116500, 2 from dual union all
10 --
11 select 6, 112342, 3 from dual union all
12 select 7, 112342, 4 from dual
13 ),
14 --
15 data as
16 (select row_num, customer, project_id,
17 row_number() over (partition by customer order by project_id) rn
18 from test
19 )
20 -- final query
21 select row_num, customer, project_id,
22 --
23 case when rn = 1 then 'GENERAL PROJECT'
24 else 'PROJECT-' || project_id
25 end as project_name
26 from data
27 order by row_Num;
ROW_NUM CUSTOMER PROJECT_ID PROJECT_NAME
---------- ---------- ---------- -------------------------
1 115432 1 GENERAL PROJECT
2 115432 2 PROJECT-2
3 115432 3 PROJECT-3
4 116500 1 GENERAL PROJECT
5 116500 2 PROJECT-2
6 112342 3 GENERAL PROJECT
7 112342 4 PROJECT-4
7 rows selected.
If first project number is always smaller than other projects then you can try:
select customer,project_id,
case when project_id=(select min(project_id) from table t2 where
t.customer=t2.customer) then 'General Project'
else concat('Project-',project_id)
end Project_Name
from table t ;
This works in mysql.
Trainee here.
I need to create a list last names from the same table.
say we have a table named "sample", this table only consists of:
What I want to do here is both last name column will be selected but have different order, the first column would be ascending and the second column would be descending like the photo below
Here's one option: it splits first and last name into two subqueries which use row_number analytic function. It is then used to join rows.
Lines #1 - 6 represent your sample data. Query you really need begins at line #7.
SQL> with test (last_name, first_name) as
2 (select 'L1one' , 'F1one' from dual union all
3 select 'L2two' , 'F2two' from dual union all
4 select 'L3three', 'F3hthree' from dual union all
5 select 'L4four' , 'F4four' from dual
6 ),
7 ln as
8 (select last_name,
9 row_Number() over (order by last_name) rn
10 from test
11 ),
12 fn as
13 (select first_name,
14 row_number() over (order by first_name desc) rn
15 from test
16 )
17 select l.last_name, f.first_name
18 from ln l join fn f on f.rn = l.rn
19 order by l.last_name
20 /
LAST_NA FIRST_NA
------- --------
L1one F4four
L2two F3hthree
L3three F2two
L4four F1one
SQL>
[EDIT: both last names? I thought it was a typo]
If that's so, self-join is a better option:
SQL> with test (last_name, first_name) as
2 (select 'L1one' , 'F1one' from dual union all
3 select 'L2two' , 'F2two' from dual union all
4 select 'L3three', 'F3hthree' from dual union all
5 select 'L4four' , 'F4four' from dual
6 ),
7 temp as
8 (select last_name,
9 row_number() over (order by last_name asc) rna,
10 row_number() over (order by last_name desc) rnd
11 from test
12 )
13 select a.last_name, d.last_name
14 from temp a join temp d on a.rna = d.rnd
15 order by a.last_name;
LAST_NA LAST_NA
------- -------
L1one L4four
L2two L3three
L3three L2two
L4four L1one
SQL>
Here is one way to do it. In a single subquery, assign the ordinal number (rn) based on ascending order, but also keep track of the total row count. Then follow with a join.
with
test (last_name, first_name) as (
select 'L1one' , 'F1one' from dual union all
select 'L2two' , 'F2two' from dual union all
select 'L3three', 'F3hthree' from dual union all
select 'L4four' , 'F4four' from dual
)
, prep (last_name, rn, ct) as (
select last_name, row_number() over (order by last_name), count(*) over ()
from test
)
select a.last_name as last_name_asc, b.last_name as last_name_desc
from prep a inner join prep b on a.rn + b.rn = a.ct + 1
;
LAST_NAME_ASC LAST_NAME_DESC
-------------- --------------
L1one L4four
L2two L3three
L3three L2two
L4four L1one
I am trying to write a Query to show Id, Name and No. of department in given Table which are referring more than one department.
ID Name Department
-- ---- ----------
1 Sam HR
1 Sam FINANCE
2 Ron PAYROLL
3 Kia HR
3 Kia IT
Result :
ID Name Department
-- ---- ----------
1 Sam 2
3 Kia 2
I tried using group by id and using count(*), but query is giving error.
How can I do this?
Without seeing your query, a blind guess is that you wrongly wrote the GROUP BY clause (if you used it) and forgot to include the HAVING clause.
Anyway, something like this might be what you're looking for:
SQL> with test (id, name, department) as
2 (select 1, 'sam', 'hr' from dual union
3 select 1, 'sam', 'finance' from dual union
4 select 2, 'ron', 'payroll' from dual union
5 select 3, 'kia', 'hr' from dual union
6 select 3, 'kia', 'it' from dual
7 )
8 select id, name, count(*)
9 from test
10 group by id, name
11 having count(*) > 1
12 order by id;
ID NAM COUNT(*)
---------- --- ----------
1 sam 2
3 kia 2
SQL>
You were right about using count(). You need to group by other columns though and only count unique departments then filter on the number in having clause.
select id, name, count(distinct department) as no_of_department
from table
group by id, name
having count(distinct department) > 1
This can also be done using analytic functions like below:
select *
from (
select id, name, count(distinct department) over (partition by id, name) as no_of_department
from table
) t
where no_of_department > 1
You can use window function with subquery :
select distinct id, name, Noofdepartment
from (select t.*, count(*) over (partition by id,name) Noofdepartment
from table t
) t
where Noofdepartment > 1;
However, you can also use group by clause:
select id, name, count(*) as Noofdepartment
from table t
group by id, name
having count(*) > 1;
Here is my table:
ID Name Department
1 Michael Marketing
2 Alex Marketing
3 Tom Marketing
4 John Sales
5 Brad Marketing
6 Leo Marketing
7 Kevin Production
I am trying to find ID ranges where Department = 'Marketing':
Range From To
Range1 1 3
Range2 5 6
Any help would be appreciated.
This is easy to do with a technique called Tabibitosan.
What this technique does is compare the positions of each group's rows to the overall set of rows, in order to work out if rows in the same group are next to each other or not.
E.g., with your example data, this looks like:
WITH your_table AS (SELECT 1 ID, 'Michael' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 2 ID, 'Alex' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 3 ID, 'Tom' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 4 ID, 'John' NAME, 'Sales' department FROM dual UNION ALL
SELECT 5 ID, 'Brad' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 6 ID, 'Leo' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 7 ID, 'Kevin' NAME, 'Production' department FROM dual)
-- end of mimicking your table with data in it. See the SQL below:
SELECT ID,
NAME,
department,
row_number() OVER (ORDER BY ID) overall_rn,
row_number() OVER (PARTITION BY department ORDER BY ID) department_rn,
row_number() OVER (ORDER BY ID) - row_number() OVER (PARTITION BY department ORDER BY ID) grp
FROM your_table;
ID NAME DEPARTMENT OVERALL_RN DEPARTMENT_RN GRP
---------- ------- ---------- ---------- ------------- ----------
1 Michael Marketing 1 1 0
2 Alex Marketing 2 2 0
3 Tom Marketing 3 3 0
4 John Sales 4 1 3
5 Brad Marketing 5 4 1
6 Leo Marketing 6 5 1
7 Kevin Production 7 1 6
Here, I've given all the rows across the entire set of data a row number in ascending id order (the overall_rn column), and I've given the rows in each department a row number (the department_rn column), again in ascending id order.
Now that I've done that, we can subtract one from the other (the grp column).
Notice how the number in the grp column remains the same for deparment rows that are next to each other, but it changes each time there's a gap.
E.g. for the Marketing department, rows 1-3 are next to each other and have grp = 0, but the 4th Marketing row is actually on the 5th row of the overall results set, so it now has a different grp number. Since the 5th marketing row is on the 6th row of the overall set, it has the same grp number as the 4th marketing row, so we know they're next to each other.
Once we have that grp information, it's a simple matter of doing an aggregate query grouping on both the department and our new grp column, using min and max to find the start and end ids:
WITH your_table AS (SELECT 1 ID, 'Michael' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 2 ID, 'Alex' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 3 ID, 'Tom' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 4 ID, 'John' NAME, 'Sales' department FROM dual UNION ALL
SELECT 5 ID, 'Brad' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 6 ID, 'Leo' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 7 ID, 'Kevin' NAME, 'Production' department FROM dual)
-- end of mimicking your table with data in it. See the SQL below:
SELECT department,
MIN(ID) start_id,
MAX(ID) end_id
FROM (SELECT ID,
NAME,
department,
row_number() OVER (ORDER BY ID) - row_number() OVER (PARTITION BY department ORDER BY ID) grp
FROM your_table)
GROUP BY department, grp;
DEPARTMENT START_ID END_ID
---------- ---------- ----------
Marketing 1 3
Marketing 5 6
Sales 4 4
Production 7 7
N.B., I've assumed that gaps in the id columns aren't important (i.e. if there was no row for id = 6 (so Leo and Kevin's ids were 7 and 8 respectively), then Leo and Brad would still appear in the same group, with a start id = 5 and end id = 7.
If gaps in the id columns count as indicating a new group, then you could just use the id to label the overall set of rows (i.e. no need to caluclate the overall_rn; just use the id column instead).
That means your query would become:
WITH your_table AS (SELECT 1 ID, 'Michael' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 2 ID, 'Alex' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 3 ID, 'Tom' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 4 ID, 'John' NAME, 'Sales' department FROM dual UNION ALL
SELECT 5 ID, 'Brad' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 7 ID, 'Leo' NAME, 'Marketing' department FROM dual UNION ALL
SELECT 8 ID, 'Kevin' NAME, 'Production' department FROM dual)
-- end of mimicking your table with data in it. See the SQL below:
SELECT department,
MIN(ID) start_id,
MAX(ID) end_id
FROM (SELECT ID,
NAME,
department,
ID - row_number() OVER (PARTITION BY department ORDER BY ID) grp
FROM your_table)
GROUP BY department, grp;
DEPARTMENT START_ID END_ID
---------- ---------- ----------
Marketing 1 3
Sales 4 4
Marketing 5 5
Marketing 7 7
Production 8 8
I don't have the environment currently but you can try something like this
select * from tab1 where id in
(select min(id) from tab1 where Department = 'Marketing'
union
select max(id) from tab1 where Department = 'Marketing')
Hi i am looking for a way to write a SQL statement which will come out with the following results :-
Lets say we have Dept & Emp ID i would like to generate like records from Dept 3 for the first two rows then followed by Dept 2 with one row then continue Dept 3 and so on :
DEPT EMPID
----- ------
3 1
3 2
2 3
3 7
3 8
2 9
Thank You.
You could use something like this
SELECT
DEPT,
EMPID
FROM (
SELECT
*,
ceil((row_number() OVER (PARTITION BY dept ORDER BY EMPID ))/ 2::numeric(5,2)) AS multiple_row_dept,
row_number() OVER (PARTITION BY dept ORDER BY EMPID ) AS single_row_dept
FROM
test_data2
) sub_query
ORDER BY
CASE
WHEN DEPT = 2 THEN single_row_dept
ELSE multiple_row_dept
END,
DEPT DESC,
EMPID
single_row_dept specifics which dept should appear only once, in this case its DEPT 2 followed by multiple other departments
First order a table by empid in a subquery,
then calculate a remainder of rowids divided by 3,
then depending on a result of calculation, return 2 or 3, using case expression,
like this
SELECT
CASE REMAINDER( rownum, 3 )
WHEN 0 THEN 2
ELSE 3
END As DeptId,
empid
FROM (
SELECT empid
FROM table1
ORDER BY empid
)
demo: http://sqlfiddle.com/#!4/bd1bb/3
The following code has some limitations:
1) There are only 2 DepId's in the source table
2) Ratio between records having different DepId is exactly 2:1
3) Ordering in one place of the query should be changed depending whether DeptId having more records is naturally greater then the other or not
with t as (
select 3 dept_id, 1 emp_id from dual
union all
select 3, 2 from dual
union all
select 3, 7 from dual
union all
select 3, 8 from dual
union all
select 2, 3 from dual
union all
select 2, 9 from dual)
select dept_id, emp_id
from (select dept_id,
emp_id,
dense_rank() over(partition by dept_id order by in_num + mod(in_num, out_num)) ord
from (select dept_id,
emp_id,
row_number() over(partition by dept_id order by emp_id) in_num,
/*in the following ORDER BY change to DESC or ASC depending on which dept_id has more records*/
dense_rank() over(order by dept_id) out_num
from t))
order by ord, dept_id desc;
DEPT_ID EMP_ID
---------- ----------
3 1
3 2
2 3
3 8
3 7
2 9