Related
This query takes dynamic input in the place of cg.ownerid IN (294777,228649 ,188464).when the input increases in the IN condition the query is taking too much time to execute. Please suggest me a way to optimize it.
For example, the below query is taking 4 seconds, if I reduce the list to just IN(188464) its just taking 1 second.
SELECT *
FROM
(SELECT *,
Row_number() OVER(
ORDER BY datecreated DESC) AS rownum
FROM
(SELECT DISTINCT c.itemid,
(CASE WHEN (Isnull(c.password, '') <> '') THEN 1 ELSE 0 END) AS password,
c.title,
c.encoderid,
c.type,
(CASE WHEN c.author = 'education' THEN 'Discovery' ELSE c.type END) AS TYPE,
c.publisher,
c.description,
c.author,
c.duration,
c.copyright,
c.rating,
c.userid,
Stuff(
(SELECT DISTINCT ' ' + NAME AS [text()]
FROM firsttable SUB
LEFT JOIN secondtable AS rgc ON thirdtable = rgc.id
WHERE SUB.itemid = c.itemid
FOR xml path('')), 1, 1, '')AS [Sub_Categories]
FROM fourthtable AS cg
LEFT JOIN item AS c ON c.itemid = cg.itemid
WHERE Isnull(title, '') <> ''
AND c.active = '1'
AND c.systemid = '20'
AND cg.ownerid IN (294777,
228649,
188464)) AS a) AS b
WHERE rownum BETWEEN 1 AND 32
ORDER BY datecreated DESC
As I haven't further information, I just would suggest a first change of your where clause. They should be moved to a subquery as you left join those columns.
SELECT *
FROM(
SELECT *,
Row_number() OVER(
ORDER BY datecreated DESC) AS rownum
FROM
(SELECT DISTINCT c.itemid,
(CASE WHEN (Isnull(c.password, '') <> '') THEN 1 ELSE 0 END) AS password,
c.title,
c.encoderid,
c.type,
(CASE WHEN c.author = 'education' THEN 'Discovery' ELSE c.type END) AS TYPE,
c.publisher,
c.description,
c.author,
c.duration,
c.copyright,
c.rating,
c.userid,
Stuff(
(
SELECT DISTINCT ' ' + NAME AS [text()]
FROM firsttable SUB
LEFT JOIN secondtable AS rgc ON thirdtable = rgc.id
WHERE SUB.itemid = c.itemid
FOR xml path('')
), 1, 1, ''
) AS [Sub_Categories]
FROM (
SELECT cg.itemid
FROM fourthtable as cg
WHERE cg.ownerid IN (294777,228649, 188464)
) AS cg
LEFT JOIN (
SELECT DISTINCT c.itemid, c.type, c.author, c.title, c.encoderid, c.type, c.publisher, c.description, c.author, c.duration, c.copyright, c.rating,c.userid
FROM item as c
WHERE Isnull(c.title, '') <> ''
AND c.active = '1'
AND c.systemid = '20'
) AS c
ON c.itemid = cg.itemid
) AS a
) AS b
WHERE rownum BETWEEN 1 AND 32
ORDER BY datecreated DESC
But not quite sure if everything is connected right away, your missing some aliases which makes it hard for me to get through your query. But I thing you'll get my idea. :-)
With this little information it's impossible to give any specific ideas, but the normal general things apply:
Turn on statistics io and check what's causing most of the logical I/O and try to solve that
Look at the actual plan and check if there's something that doesn't look ok, for example:
Clustered index / table scans (new index could solve this)
Key lookups with a huge amount of rows (adding more columns to index could solve this, either as normal or included fields)
Spools (new index could solve this)
Big difference between estimated and actual number of rows (10x, 100x and so on)
To give any better hints you should really include the actual plan, table / index structure at least on the essential parts and tell what is too much time (seconds, minutes, hours?)
the first query:
SELECT u.id , prop1.id
FROM ( SELECT '9fbc6e9b59504c08ac643752c1e2d033' AS id ,
'|6813dbbfec6241a19b8d2316d2cb2a65,1|' AS customprop
UNION
SELECT 'f2271c45682f45fc84527c4afff0ab16' AS id ,
'|6813dbbfec6241a19b8d2316d2cb2a65,2|' AS customprop
) u
INNER JOIN ( SELECT ROW_NUMBER() OVER ( ORDER BY a.Id ) id ,
A.Id propId ,
B.NAME
FROM ( SELECT '6813dbbfec6241a19b8d2316d2cb2a65' AS id ,
CONVERT(XML, '<v>1,职业资格1</v><v>2,职业资格2</v>') AS value
) A
OUTER APPLY ( SELECT Name = N.v.value('.',
'nvarchar(Max)')
FROM A.[VALUE].nodes('/v') N ( v )
) B
) prop1 ON CHARINDEX('|' + prop1.propid + ','
+ CONVERT(NVARCHAR(10), prop1.id)
+ '|', u.customprop) > 0
GROUP BY u.id ,
prop1.id
the second query:
SELECT u.id ,prop1.id, count(*)
FROM ( SELECT '9fbc6e9b59504c08ac643752c1e2d033' AS id ,
'|6813dbbfec6241a19b8d2316d2cb2a65,1|' AS customprop
UNION
SELECT 'f2271c45682f45fc84527c4afff0ab16' AS id ,
'|6813dbbfec6241a19b8d2316d2cb2a65,2|' AS customprop
) u
INNER JOIN ( SELECT ROW_NUMBER() OVER ( ORDER BY a.Id ) id ,
A.Id propId ,
B.NAME
FROM ( SELECT '6813dbbfec6241a19b8d2316d2cb2a65' AS id ,
CONVERT(XML, '<v>1,职业资格1</v><v>2,职业资格2</v>') AS value
) A
OUTER APPLY ( SELECT Name = N.v.value('.',
'nvarchar(Max)')
FROM A.[VALUE].nodes('/v') N ( v )
) B
) prop1 ON CHARINDEX('|' + prop1.propid + ','
+ CONVERT(NVARCHAR(10), prop1.id)
+ '|', u.customprop) > 0
GROUP BY u.id ,
prop1.id
sql can be executed on sqlserver 2005 directly.
the first query can produce one item and the second query produce two items.
I think that the two queries should both produce two items.
I have thouht for three days and I really want to konw why.
I'm a Chinese and my English is poor.I hope you can understand my description
Tough question, but the problem is with this line:
INNER JOIN ( SELECT ROW_NUMBER() OVER ( ORDER BY a.Id ) id ,
The ORDER BY is ambiguous and consequently, if it is executed multiple times (which it can be because of the INNER JOIN it is contained in), it may not always return the same ordering/assignment. This can cause a latter join condition to only match on one record instead of two, which is what happens in the query plan being used for the version without the count(*) column.
To fix this, you just need to add something to make the ordering assignment unique, like this:
INNER JOIN ( SELECT ROW_NUMBER() OVER ( ORDER BY a.Id, B.Name ASC ) id ,
Try it like this, it should work.
Your problem is with the ORDER BY clause of the ROW_NUMBER - since the a.ID is not unique the outcome is unpredictable. Make that unique and your problem will go away - you can use something like
...SELECT ROW_NUMBER() OVER ( ORDER BY newid() ) id...
Given the following PostgreSQL table:
items
integer id
integer parent_id
string name
unique key on [parent_id, name]
parent_id is null for all root nodes
Currently I build the sql query manually, doing a join for every path element. But is seems quite ugly to me and of course it limits the possible depth.
Example:
path: holiday,images,spain
SELECT i3.*
FROM items AS i1
, items AS i2
, items AS i3
WHERE i1.parent_id IS NULL AND i1.name = 'holiday'
AND i2.parent_id=i1.id AND i2.name = 'images'
AND i3.parent_id=i2.id AND i3.name = 'spain'
I wonder if there's a better way, probably using CTE?
You can see how my current code works and what the expected output is here:
http://sqlfiddle.com/#!1/4537c/2
update2 here's a function, it peforms well, because search goes only within the path, starting from parent:
create or replace function get_item(path text[])
returns items
as
$$
with recursive cte as (
select i.id, i.name, i.parent_id, 1 as level
from items as i
where i.parent_id is null and i.name = $1[1]
union all
select i.id, i.name, i.parent_id, c.level + 1
from items as i
inner join cte as c on c.id = i.parent_id
where i.name = $1[level + 1]
)
select c.id, c.parent_id, c.name
from cte as c
where c.level = array_length($1, 1)
$$
language sql;
sql fiddle demo
update I think you can do recursive traversal. I've written sql version of this, so it's a bit messy because of cte, but it's possible to write a function:
with recursive cte_path as (
select array['holiday', 'spain', '2013'] as arr
), cte as (
select i.id, i.name, i.parent_id, 1 as level
from items as i
cross join cte_path as p
where i.parent_id is null and name = p.arr[1]
union all
select i.id, i.name, i.parent_id, c.level + 1
from items as i
inner join cte as c on c.id = i.parent_id
cross join cte_path as p
where i.name = p.arr[level + 1]
)
select c.*
from cte as c
cross join cte_path as p
where level = array_length(p.arr, 1)
sql fiddle demo
or you can build path for all of the elements using recursive cte for that and accumuate your path into array or string:
with recursive cte as (
select i.id, i.name, i.parent_id, i.name::text as path
from items as i
where i.parent_id is null
union all
select i.id, i.name, i.parent_id, c.path || '->' || i.name::text as path
from items as i
inner join cte as c on c.id = i.parent_id
)
select *
from cte
where path = 'holiday->spain->2013';
or
with recursive cte as (
select i.id, i.name, i.parent_id, array[i.name::text] as path
from items as i
where i.parent_id is null
union all
select i.id, i.name, i.parent_id, c.path || array[i.name::text] as path
from items as i
inner join cte as c on c.id = i.parent_id
)
select *
from cte
where path = array['holiday', 'spain', '2013']
sql fiddle demo
This should perform very well, as it eliminates impossible paths immediately:
WITH RECURSIVE cte AS (
SELECT id, parent_id, name
,'{holiday,spain,2013}'::text[] AS path -- provide path as array here
,2 AS lvl -- next level
FROM items
WHERE parent_id IS NULL
AND name = 'holiday' -- being path[1]
UNION ALL
SELECT i.id, i.parent_id, i.name
,cte.path, cte.lvl + 1
FROM cte
JOIN items i ON i.parent_id = cte.id AND i.name = path[lvl]
)
SELECT id, parent_id, name
FROM cte
ORDER BY lvl DESC
LIMIT 1;
Assuming you provide a unique path (only 1 result).
->SQLfiddle demo
Too late to post my answer (very equivalent to Roman's and Erwin's) But an improvement on the table definition instead:
CREATE TABLE items
( id integer NOT NULL PRIMARY KEY
, parent_id integer REFERENCES items(id)
, name varchar
, UNIQUE (parent_id,name) -- I don't actually like this one
); -- ; UNIQUE on a NULLable column ...
INSERT INTO items (id, parent_id, name) values
(1, null, 'holiday')
, (2, 1, 'spain'), (3, 2, '2013')
, (4, 1, 'usa'), (5, 4, '2013')
;
I have 3 tables called:
Applications (id, name)
Resources (id, name)
ApplicationsResources (id, app_id, resource_id)
I want to show on a GUI a table of all resource names. In one cell in each row I would like to list out all of the applications (comma separated) of that resource.
So the question is, what is the best way to do this in SQL as I need to get all resources and I also need to get all applications for each resource?
Do I run a select * from resources first and then loop through each resource and do a separate query per resource to get the list of applications for that resource?
Is there a way I can do this in one query?
MySQL
SELECT r.name,
GROUP_CONCAT(a.name SEPARATOR ',')
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar ON ar.resource_id = r.id
JOIN APPLICATIONS a ON a.id = ar.app_id
GROUP BY r.name
SQL Server (2005+)
SELECT r.name,
STUFF((SELECT ',' + a.name
FROM APPLICATIONS a
JOIN APPLICATIONRESOURCES ar ON ar.app_id = a.id
WHERE ar.resource_id = r.id
GROUP BY a.name
FOR XML PATH(''), TYPE).value('text()[1]','NVARCHAR(max)'), 1, LEN(','), '')
FROM RESOURCES r
SQL Server (2017+)
SELECT r.name,
STRING_AGG(a.name, ',')
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar ON ar.resource_id = r.id
JOIN APPLICATIONS a ON a.id = ar.app_id
GROUP BY r.name
Oracle
I recommend reading about string aggregation/concatentation in Oracle.
NOTE:
This method is not recommended as it can give incorrect or non-deterministic results.
This has been documented on StackOverflow and DBA
Using COALESCE to Build Comma-Delimited String in SQL Server
http://www.sqlteam.com/article/using-coalesce-to-build-comma-delimited-string
Example:
DECLARE #EmployeeList varchar(100)
SELECT #EmployeeList = COALESCE(#EmployeeList + ', ', '') +
CAST(Emp_UniqueID AS varchar(5))
FROM SalesCallsEmployees
WHERE SalCal_UniqueID = 1
SELECT #EmployeeList
I don't know if there's any solution to do this in a database-agnostic way, since you most likely will need some form of string manipulation, and those are typically different between vendors.
For SQL Server 2005 and up, you could use:
SELECT
r.ID, r.Name,
Resources = STUFF(
(SELECT ','+a.Name
FROM dbo.Applications a
INNER JOIN dbo.ApplicationsResources ar ON ar.app_id = a.id
WHERE ar.resource_id = r.id
FOR XML PATH('')), 1, 1, '')
FROM
dbo.Resources r
It uses the SQL Server 2005 FOR XML PATH construct to list the subitems (the applications for a given resource) as a comma-separated list.
Marc
I believe what you want is:
SELECT ItemName, GROUP_CONCAT(DepartmentId) FROM table_name GROUP BY ItemName
If you're using MySQL
Reference
http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat
Assuming SQL Server:
Table structure:
CREATE TABLE [dbo].[item_dept](
[ItemName] char(20) NULL,
[DepartmentID] int NULL
)
Query:
SELECT ItemName,
STUFF((SELECT ',' + rtrim(convert(char(10),DepartmentID))
FROM item_dept b
WHERE a.ItemName = b.ItemName
FOR XML PATH('')),1,1,'') DepartmentID
FROM item_dept a
GROUP BY ItemName
Results:
ItemName DepartmentID
item1 21,13,9,36
item2 4,9,44
I think we could write in the following way to retrieve(below code is just an example, please modify as needed):
Create FUNCTION dbo.ufnGetEmployeeMultiple(#DepartmentID int)
RETURNS VARCHAR(1000) AS
BEGIN
DECLARE #Employeelist varchar(1000)
SELECT #Employeelist = COALESCE(#Employeelist + ', ', '') + E.LoginID
FROM humanresources.Employee E
Left JOIN humanresources.EmployeeDepartmentHistory H ON
E.BusinessEntityID = H.BusinessEntityID
INNER JOIN HumanResources.Department D ON
H.DepartmentID = D.DepartmentID
Where H.DepartmentID = #DepartmentID
Return #Employeelist
END
SELECT D.name as Department, dbo.ufnGetEmployeeMultiple (D.DepartmentID)as Employees
FROM HumanResources.Department D
SELECT Distinct (D.name) as Department, dbo.ufnGetEmployeeMultiple (D.DepartmentID) as
Employees
FROM HumanResources.Department D
From next version of SQL Server you will be able to do
SELECT r.name,
STRING_AGG(a.name, ',')
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar
ON ar.resource_id = r.id
JOIN APPLICATIONS a
ON a.id = ar.app_id
GROUP BY r.name
For previous versions of the product there are quite a wide variety of different approaches to this problem. An excellent review of them is in the article: Concatenating Row Values in Transact-SQL.
Concatenating values when the number of items are not known
Recursive CTE method
The blackbox XML methods
Using Common Language Runtime
Scalar UDF with recursion
Table valued UDF with a WHILE loop
Dynamic SQL
The Cursor approach
.
Non-reliable approaches
Scalar UDF with t-SQL update extension
Scalar UDF with variable concatenation in SELECT
MySQL
SELECT r.name,
GROUP_CONCAT(a.name SEPARATOR ',')
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar ON ar.resource_id = r.id
JOIN APPLICATIONS a ON a.id = ar.app_id
GROUP BY r.name
**
MS SQL Server
SELECT r.name,
STUFF((SELECT ','+ a.name
FROM APPLICATIONS a
JOIN APPLICATIONRESOURCES ar ON ar.app_id = a.id
WHERE ar.resource_id = r.id
GROUP BY a.name
FOR XML PATH(''), TYPE).value('.','VARCHAR(max)'), 1, 1, '')
FROM RESOURCES r
GROUP BY deptno;
Oracle
SELECT r.name,
LISTAGG(a.name SEPARATOR ',') WITHIN GROUP (ORDER BY a.name)
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar ON ar.resource_id = r.id
JOIN APPLICATIONS a ON a.id = ar.app_id
GROUP BY r.name;
There is no way to do it in a DB-agnostic way.
So you need to get the whole data-set like this:
select
r.name as ResName,
a.name as AppName
from
Resouces as r,
Applications as a,
ApplicationsResources as ar
where
ar.app_id = a.id
and ar.resource_id = r.id
And then concat the AppName programmatically while grouping by ResName.
To be agnostic, drop back and punt.
Select a.name as a_name, r.name as r_name
from ApplicationsResource ar, Applications a, Resources r
where a.id = ar.app_id
and r.id = ar.resource_id
order by r.name, a.name;
Now user your server programming language to concatenate a_names while r_name is the same as the last time.
This will do it in SQL Server:
DECLARE #listStr VARCHAR(MAX)
SELECT #listStr = COALESCE(#listStr+',' ,'') + Convert(nvarchar(8),DepartmentId)
FROM Table
SELECT #listStr
I have 3 tables called:
Applications (id, name)
Resources (id, name)
ApplicationsResources (id, app_id, resource_id)
I want to show on a GUI a table of all resource names. In one cell in each row I would like to list out all of the applications (comma separated) of that resource.
So the question is, what is the best way to do this in SQL as I need to get all resources and I also need to get all applications for each resource?
Do I run a select * from resources first and then loop through each resource and do a separate query per resource to get the list of applications for that resource?
Is there a way I can do this in one query?
MySQL
SELECT r.name,
GROUP_CONCAT(a.name SEPARATOR ',')
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar ON ar.resource_id = r.id
JOIN APPLICATIONS a ON a.id = ar.app_id
GROUP BY r.name
SQL Server (2005+)
SELECT r.name,
STUFF((SELECT ',' + a.name
FROM APPLICATIONS a
JOIN APPLICATIONRESOURCES ar ON ar.app_id = a.id
WHERE ar.resource_id = r.id
GROUP BY a.name
FOR XML PATH(''), TYPE).value('text()[1]','NVARCHAR(max)'), 1, LEN(','), '')
FROM RESOURCES r
SQL Server (2017+)
SELECT r.name,
STRING_AGG(a.name, ',')
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar ON ar.resource_id = r.id
JOIN APPLICATIONS a ON a.id = ar.app_id
GROUP BY r.name
Oracle
I recommend reading about string aggregation/concatentation in Oracle.
NOTE:
This method is not recommended as it can give incorrect or non-deterministic results.
This has been documented on StackOverflow and DBA
Using COALESCE to Build Comma-Delimited String in SQL Server
http://www.sqlteam.com/article/using-coalesce-to-build-comma-delimited-string
Example:
DECLARE #EmployeeList varchar(100)
SELECT #EmployeeList = COALESCE(#EmployeeList + ', ', '') +
CAST(Emp_UniqueID AS varchar(5))
FROM SalesCallsEmployees
WHERE SalCal_UniqueID = 1
SELECT #EmployeeList
I don't know if there's any solution to do this in a database-agnostic way, since you most likely will need some form of string manipulation, and those are typically different between vendors.
For SQL Server 2005 and up, you could use:
SELECT
r.ID, r.Name,
Resources = STUFF(
(SELECT ','+a.Name
FROM dbo.Applications a
INNER JOIN dbo.ApplicationsResources ar ON ar.app_id = a.id
WHERE ar.resource_id = r.id
FOR XML PATH('')), 1, 1, '')
FROM
dbo.Resources r
It uses the SQL Server 2005 FOR XML PATH construct to list the subitems (the applications for a given resource) as a comma-separated list.
Marc
I believe what you want is:
SELECT ItemName, GROUP_CONCAT(DepartmentId) FROM table_name GROUP BY ItemName
If you're using MySQL
Reference
http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat
Assuming SQL Server:
Table structure:
CREATE TABLE [dbo].[item_dept](
[ItemName] char(20) NULL,
[DepartmentID] int NULL
)
Query:
SELECT ItemName,
STUFF((SELECT ',' + rtrim(convert(char(10),DepartmentID))
FROM item_dept b
WHERE a.ItemName = b.ItemName
FOR XML PATH('')),1,1,'') DepartmentID
FROM item_dept a
GROUP BY ItemName
Results:
ItemName DepartmentID
item1 21,13,9,36
item2 4,9,44
I think we could write in the following way to retrieve(below code is just an example, please modify as needed):
Create FUNCTION dbo.ufnGetEmployeeMultiple(#DepartmentID int)
RETURNS VARCHAR(1000) AS
BEGIN
DECLARE #Employeelist varchar(1000)
SELECT #Employeelist = COALESCE(#Employeelist + ', ', '') + E.LoginID
FROM humanresources.Employee E
Left JOIN humanresources.EmployeeDepartmentHistory H ON
E.BusinessEntityID = H.BusinessEntityID
INNER JOIN HumanResources.Department D ON
H.DepartmentID = D.DepartmentID
Where H.DepartmentID = #DepartmentID
Return #Employeelist
END
SELECT D.name as Department, dbo.ufnGetEmployeeMultiple (D.DepartmentID)as Employees
FROM HumanResources.Department D
SELECT Distinct (D.name) as Department, dbo.ufnGetEmployeeMultiple (D.DepartmentID) as
Employees
FROM HumanResources.Department D
From next version of SQL Server you will be able to do
SELECT r.name,
STRING_AGG(a.name, ',')
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar
ON ar.resource_id = r.id
JOIN APPLICATIONS a
ON a.id = ar.app_id
GROUP BY r.name
For previous versions of the product there are quite a wide variety of different approaches to this problem. An excellent review of them is in the article: Concatenating Row Values in Transact-SQL.
Concatenating values when the number of items are not known
Recursive CTE method
The blackbox XML methods
Using Common Language Runtime
Scalar UDF with recursion
Table valued UDF with a WHILE loop
Dynamic SQL
The Cursor approach
.
Non-reliable approaches
Scalar UDF with t-SQL update extension
Scalar UDF with variable concatenation in SELECT
MySQL
SELECT r.name,
GROUP_CONCAT(a.name SEPARATOR ',')
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar ON ar.resource_id = r.id
JOIN APPLICATIONS a ON a.id = ar.app_id
GROUP BY r.name
**
MS SQL Server
SELECT r.name,
STUFF((SELECT ','+ a.name
FROM APPLICATIONS a
JOIN APPLICATIONRESOURCES ar ON ar.app_id = a.id
WHERE ar.resource_id = r.id
GROUP BY a.name
FOR XML PATH(''), TYPE).value('.','VARCHAR(max)'), 1, 1, '')
FROM RESOURCES r
GROUP BY deptno;
Oracle
SELECT r.name,
LISTAGG(a.name SEPARATOR ',') WITHIN GROUP (ORDER BY a.name)
FROM RESOURCES r
JOIN APPLICATIONSRESOURCES ar ON ar.resource_id = r.id
JOIN APPLICATIONS a ON a.id = ar.app_id
GROUP BY r.name;
There is no way to do it in a DB-agnostic way.
So you need to get the whole data-set like this:
select
r.name as ResName,
a.name as AppName
from
Resouces as r,
Applications as a,
ApplicationsResources as ar
where
ar.app_id = a.id
and ar.resource_id = r.id
And then concat the AppName programmatically while grouping by ResName.
To be agnostic, drop back and punt.
Select a.name as a_name, r.name as r_name
from ApplicationsResource ar, Applications a, Resources r
where a.id = ar.app_id
and r.id = ar.resource_id
order by r.name, a.name;
Now user your server programming language to concatenate a_names while r_name is the same as the last time.
This will do it in SQL Server:
DECLARE #listStr VARCHAR(MAX)
SELECT #listStr = COALESCE(#listStr+',' ,'') + Convert(nvarchar(8),DepartmentId)
FROM Table
SELECT #listStr