Insert Into using a WITH clause (CTE) causes a ORA-00928 - sql

I'm attempting to do an essentially very simple task, which is resulting in:
ORA-00928: missing SELECT keyword
All I'm trying to do is persist the results from periods into table globalTable. Selecting works fine (I'm returned rows) however as soon as I replace it with the Insert I get the above error.
create global temporary table globalTable
(
ids number(11)
);
with periods as
(
select cl.id uniqueId
from inv_mpan_hh_con_lines cl
left join invoice_vat_lines vl on
cl.invoice_id = VL.INVOICE_ID
where rownum < 4
)
--//Issue occurs at insert keyword. If I comment it and uncomment select it works as expected//--
--select uniqueId
insert into globalTable
from periods;
Any pointers are much appreciated.

Try this:
insert into globalTable
with periods as
(
select cl.id uniqueId
from inv_mpan_hh_con_lines cl
left join invoice_vat_lines vl
on cl.invoice_id = VL.INVOICE_ID
where rownum < 4
)
select uniqueId
from periods;
CTE (WITH-clause) is a part of SELECT statement, according to the INSERT syntax you can either specify values or SELECT statement

Related

Generating Lines based on a value from a column in another table

I have the following table:
EventID=00002,DocumentID=0005,EventDesc=ItemsReceived
I have the quantity in another table
DocumentID=0005,Qty=20
I want to generate a result of 20 lines (depending on the quantity) with an auto generated column which will have a sequence of:
ITEM_TAG_001,
ITEM_TAG_002,
ITEM_TAG_003,
ITEM_TAG_004,
..
ITEM_TAG_020
Here's your sql query.
with cte as (
select 1 as ctr, t2.Qty, t1.EventID, t1.DocumentId, t1.EventDesc from tableA t1
inner join tableB t2 on t2.DocumentId = t1.DocumentId
union all
select ctr + 1, Qty, EventID, DocumentId, EventDesc from cte
where ctr <= Qty
)select *, concat('ITEM_TAG_', right('000'+ cast(ctr AS varchar(3)),3)) from cte
option (maxrecursion 0);
Output:
Best is to introduce a numbers table, very handsome in many places...
Something along:
Create some test data:
DECLARE #MockNumbers TABLE(Number BIGINT);
DECLARE #YourTable1 TABLE(DocumentID INT,ItemTag VARCHAR(100),SomeText VARCHAR(100));
DECLARE #YourTable2 TABLE(DocumentID INT, Qty INT);
INSERT INTO #MockNumbers SELECT TOP 100 ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM master..spt_values;
INSERT INTO #YourTable1 VALUES(1,'FirstItem','qty 5'),(2,'SecondItem','qty 7');
INSERT INTO #YourTable2 VALUES(1,5), (2,7);
--The query
SELECT CONCAT(t1.ItemTag,'_',REPLACE(STR(A.Number,3),' ','0'))
FROM #YourTable1 t1
INNER JOIN #YourTable2 t2 ON t1.DocumentID=t2.DocumentID
CROSS APPLY(SELECT Number FROM #MockNumbers WHERE Number BETWEEN 1 AND t2.Qty) A;
The result
FirstItem_001
FirstItem_002
[...]
FirstItem_005
SecondItem_001
SecondItem_002
[...]
SecondItem_007
The idea in short:
We use an INNER JOIN to get the quantity joined to the item.
Now we use APPLY, which is a row-wise action, to bind as many rows to the set, as we need it.
The first item will return with 5 lines, the second with 7. And the trick with STR() and REPLACE() is one way to create a padded number. You might use FORMAT() (v2012+), but this is working rather slowly...
The table #MockNumbers is a declared table variable containing a list of numbers from 1 to 100. This answer provides an example how to create a pyhsical numbers and date table. Any database should have such a table...
If you don't want to create a numbers table, you can search for a tally table or tally on the fly. There are many answers showing approaches how to create a list of running numbers...a

Insert from select with sequence and group by

I want to insert some data into table tableA, but I have to use group by and my_sequence.nextval. It is impossible to use both in the same statment, is exists any workaround ?
For example:
insert into tableA (
taba_id,
taba_sum,
taba_date
) select
tabb_sequence.nextval,
sum(tabb_value),
tabb_date
from
tableB group by (tabb_date);
After execute this statment, I got:
ORA-02287: sequence number not allowed here
According oracle documentation,I should get this error.
How to deal with sequence and group by caluses in one statment?
The problem here is because your sequence is not aggregated, therefore you have this error. Try this way:
insert into tableA (
taba_id,
taba_date,
taba_sum
)
select tabb_sequence.nextval,
tabb_date,
stv
from (select tabb_date,
sum(tabb_value) stv,
from tableB
group by tabb_date) a;

SQL Server error - Subquery returned more than 1 value

I'm looking to insert rows of data into a table from another table, normal scenario.
Here's my current SQL script,
INSERT [dbo].[X_RPT_PORTAL_REPORTLIST] (
[PORTAL_GROUP_ID],
[REPORT_DISPLAY_NAME],
[STANDARD_REPORT],
[REPORT_PACK_VERSION],
[REPORT_PATH]
)
VALUES (
(SELECT ID FROM X_RPT_REPORTINGLIST),
(SELECT REPORT_NAME FROM X_RPT_REPORTINGLIST),
(SELECT STANDARD_REPORT FROM X_RPT_REPORTINGLIST),
(SELECT REPOPT_PACK_VERSION FROM X_RPT_REPORTINGLIST),
(SELECT PATH FROM ReportServer$PORTAL.dbo.Catalog)
)
Now my error I had return from this was:
Msg 512, Level 16, State 1, Line 1
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.
I had a thought this maybe incorrect, but I need some pointers on getting around this.
Any help or tips, is much appreciated.
Thank you
This issue arose because one or more of the subqueries you have used to provide the data for VALUES() have returned multiple records. The VALUES() construct is used by INSERT to insert one and only one record.
This usually arises when people use WHERE conditions such as WHERE value = (SELECT value FROM sub_table) and the subquery returns multiple records; hence is why the error message was versed as it was.
It is possible to follow an INSERT statement with a SELECT statement which returns the data that you want put into the table, so consider the following:
INSERT [dbo].[X_RPT_PORTAL_REPORTLIST] (
[PORTAL_GROUP_ID],
[REPORT_DISPLAY_NAME],
[STANDARD_REPORT],
[REPORT_PACK_VERSION],
[REPORT_PATH])
SELECT
r.ID
,r.REPORT_NAME
,r.STANDARD_REPORT
,r.REPOPT_PACK_VERSION
,c.PATH
FROM X_RPT_REPORTINGLIST r
CROSS JOIN ReportServer$PORTAL.dbo.Catalog c;
You're attempting to insert one row into a table and can therefore only have one value for each column in the row. This error means is that one or more of the SELECT statements in your VALUES() clause is returning more than one value.
Run each of the SELECT statements individually and see which of them are returning multiple rows and then constrain them with a WHERE clause where necessary until you get the single value from each of them that you want.
I think the error message is clear. You want to switch to insert . . . select. Something like this:
INSERT [dbo].[X_RPT_PORTAL_REPORTLIST] ([PORTAL_GROUP_ID], [REPORT_DISPLAY_NAME], [STANDARD_REPORT], [REPORT_PACK_VERSION], [REPORT_PATH])
SELECT rl.ID, rl.REPORT_NAME, rl.STANDARD_REPORT, rl.REPORT_PACK_VERSION,
c.PATH
FROM X_RPT_REPORTINGLIST JOIN
ReportServer$PORTAL.dbo.Catalog c
ON rl.??? = c.???;
It is unclear what the JOIN conditions are. If there is only one path, then you might want a CROSS JOIN.
Run following queries separately. Some of them will return multiple rows which causes the error. You can use WHERE/GROUP BY/PARTITION to avoid multiple rows.
SELECT ID FROM X_RPT_REPORTINGLIST
SELECT REPORT_NAME FROM X_RPT_REPORTINGLIST
SELECT STANDARD_REPORT FROM X_RPT_REPORTINGLIST
SELECT REPOPT_PACK_VERSION FROM X_RPT_REPORTINGLIST
SELECT PATH FROM ReportServer$PORTAL.dbo.Catalog
You can do it this way
INSERT [dbo].[X_RPT_PORTAL_REPORTLIST] ([PORTAL_GROUP_ID], [REPORT_DISPLAY_NAME], [STANDARD_REPORT], [REPORT_PACK_VERSION], [REPORT_PATH])
SELECT
a.ID, a.REPORT_NAME, a.STANDARD_REPORT, a.REPOPT_PACK_VERSION,
b.PATH
FROM
X_RPT_REPORTINGLIST a
JOIN
ReportServer$PORTAL.dbo.Catalog b ON XXXXXXX
Instead of XXXX you have to type the join condition for those two tables
the issue with the query is all the subqueries are returning more than 1 records.
i.e. :
(SELECT ID FROM X_RPT_REPORTINGLIST) line is returning more than 1 records, which is not permitted in INSERT statement.
you can use following code:
INSERT [dbo].[X_RPT_PORTAL_REPORTLIST]
([PORTAL_GROUP_ID], [REPORT_DISPLAY_NAME], [STANDARD_REPORT], [REPORT_PACK_VERSION], [REPORT_PATH])
VALUES (
(SELECT top 1 ID FROM X_RPT_REPORTINGLIST),
(SELECT top 1 REPORT_NAME FROM X_RPT_REPORTINGLIST),
(SELECT top 1 STANDARD_REPORT FROM X_RPT_REPORTINGLIST),
(SELECT top 1 REPOPT_PACK_VERSION FROM X_RPT_REPORTINGLIST),
(SELECT top 1 [PATH] FROM ReportServer$PORTAL.dbo.Catalog))
Note: changed the column name from PATH(which is a keyword ) to [PATH]
Try like this
INSERT INTO [dbo].[X_RPT_PORTAL_REPORTLIST]
([PORTAL_GROUP_ID], [REPORT_DISPLAY_NAME], [STANDARD_REPORT], [REPORT_PACK_VERSION], [REPORT_PATH])
SELECT rl.ID, rl.REPORT_NAME, rl.STANDARD_REPORT, rl.REPOPT_PACK_VERSION, c.PATH
FROM X_RPT_REPORTINGLIST rl
INNER JOIN ReportServer$PORTAL.dbo.Catalog c ON c.Name = rl.REPORT_NAME

Make SQL Select same row multiple times

I need to test my mail server. How can I make a Select statement
that selects say ID=5469 a thousand times.
If I get your meaning then a very simple way is to cross join on a derived query on a table with more than 1000 rows in it and put a top 1000 on that. This would duplicate your results 1000 times.
EDIT: As an example (This is MSSQL, I don't know if Access is much different)
SELECT
MyTable.*
FROM
MyTable
CROSS JOIN
(
SELECT TOP 1000
*
FROM
sysobjects
) [BigTable]
WHERE
MyTable.ID = 1234
You can use the UNION ALL statement.
Try something like:
SELECT * FROM tablename WHERE ID = 5469
UNION ALL
SELECT * FROM tablename WHERE ID = 5469
You'd have to repeat the SELECT statement a bunch of times but you could write a bit of VB code in Access to create a dynamic SQL statement and then execute it. Not pretty but it should work.
Create a helper table for this purpose:
JUST_NUMBER(NUM INT primary key)
Insert (with the help of some (VB) script) numbers from 1 to N. Then execute this unjoined query:
SELECT MYTABLE.*
FROM MYTABLE,
JUST_NUMBER
WHERE MYTABLE.ID = 5469
AND JUST_NUMBER.NUM <= 1000
Here's a way of using a recursive common table expression to generate some empty rows, then to cross join them back onto your desired row:
declare #myData table (val int) ;
insert #myData values (666),(888),(777) --some dummy data
;with cte as
(
select 100 as a
union all
select a-1 from cte where a>0
--generate 100 rows, the max recursion depth
)
,someRows as
(
select top 1000 0 a from cte,cte x1,cte x2
--xjoin the hundred rows a few times
--to generate 1030301 rows, then select top n rows
)
select m.* from #myData m,someRows where m.val=666
substitute #myData for your real table, and alter the final predicate to suit.
easy way...
This exists only one row into the DB
sku = 52 , description = Skullcandy Inkd Green ,price = 50,00
Try to relate another table in which has no constraint key to the main table
Original Query
SELECT Prod_SKU , Prod_Descr , Prod_Price FROM dbo.TB_Prod WHERE Prod_SKU = N'52'
The Functional Query ...adding a not related table called 'dbo.TB_Labels'
SELECT TOP ('times') Prod_SKU , Prod_Descr , Prod_Price FROM dbo.TB_Prod,dbo.TB_Labels WHERE Prod_SKU = N'52'
In postgres there is a nice function called generate_series. So in postgreSQL it is as simple as:
select information from test_table, generate_series(1, 1000) where id = 5469
In this way, the query is executed 1000 times.
Example for postgreSQL:
CREATE EXTENSION IF NOT EXISTS "uuid-ossp"; --To be able to use function uuid_generate_v4()
--Create a test table
create table test_table (
id serial not null,
uid UUID NOT NULL,
CONSTRAINT uid_pk PRIMARY KEY(id));
-- Insert 10000 rows
insert into test_table (uid)
select uuid_generate_v4() from generate_series(1, 10000);
-- Read the data from id=5469 one thousand times
select id, uid, uuid_generate_v4() from test_table, generate_series(1, 1000) where id = 5469;
As you can see in the result below, the data from uid is read 1000 times as confirmed by the generation of a new uuid at every new row.
id |uid |uuid_generate_v4
----------------------------------------------------------------------------------------
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"5630cd0d-ee47-4d92-9ee3-b373ec04756f"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"ed44b9cb-c57f-4a5b-ac9a-55bd57459c02"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"3428b3e3-3bb2-4e41-b2ca-baa3243024d9"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"7c8faf33-b30c-4bfa-96c8-1313a4f6ce7c"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"b589fd8a-fec2-4971-95e1-283a31443d73"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"8b9ab121-caa4-4015-83f5-0c2911a58640"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"7ef63128-b17c-4188-8056-c99035e16c11"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"5bdc7425-e14c-4c85-a25e-d99b27ae8b9f"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"9bbd260b-8b83-4fa5-9104-6fc3495f68f3"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"c1f759e1-c673-41ef-b009-51fed587353c"
5469|"10791df5-ab72-43b6-b0a5-6b128518e5ee"|"4a70bf2b-ddf5-4c42-9789-5e48e2aec441"
Of course other DBs won't necessarily have the same function but it could be done:
See here.
If your are doing this in sql Server
declare #cnt int
set #cnt = 0
while #cnt < 1000
begin
select '12345'
set #cnt = #cnt + 1
end
select '12345' can be any expression
Repeat rows based on column value of TestTable. First run the Create table and insert statement, then run the following query for the desired result.
This may be another solution:
CREATE TABLE TestTable
(
ID INT IDENTITY(1,1),
Col1 varchar(10),
Repeats INT
)
INSERT INTO TESTTABLE
VALUES ('A',2), ('B',4),('C',1),('D',0)
WITH x AS
(
SELECT TOP (SELECT MAX(Repeats)+1 FROM TestTable) rn = ROW_NUMBER()
OVER (ORDER BY [object_id])
FROM sys.all_columns
ORDER BY [object_id]
)
SELECT * FROM x
CROSS JOIN TestTable AS d
WHERE x.rn <= d.Repeats
ORDER BY Col1;
This trick helped me in my requirement.
here, PRODUCTDETAILS is my Datatable
and orderid is my column.
declare #Req_Rows int = 12
;WITH cte AS
(
SELECT 1 AS Number
UNION ALL
SELECT Number + 1 FROM cte WHERE Number < #Req_Rows
)
SELECT PRODUCTDETAILS.*
FROM cte, PRODUCTDETAILS
WHERE PRODUCTDETAILS.orderid = 3
create table #tmp1 (id int, fld varchar(max))
insert into #tmp1 (id, fld)
values (1,'hello!'),(2,'world'),(3,'nice day!')
select * from #tmp1
go
select * from #tmp1 where id=3
go 1000
drop table #tmp1
in sql server try:
print 'wow'
go 5
output:
Beginning execution loop
wow
wow
wow
wow
wow
Batch execution completed 5 times.
The easy way is to create a table with 1000 rows. Let's call it BigTable. Then you would query for the data you want and join it with the big table, like this:
SELECT MyTable.*
FROM MyTable, BigTable
WHERE MyTable.ID = 5469

SQL Server 2005 recursive query with loops in data - is it possible?

I've got a standard boss/subordinate employee table. I need to select a boss (specified by ID) and all his subordinates (and their subrodinates, etc). Unfortunately the real world data has some loops in it (for example, both company owners have each other set as their boss). The simple recursive query with a CTE chokes on this (maximum recursion level of 100 exceeded). Can the employees still be selected? I care not of the order in which they are selected, just that each of them is selected once.
Added: You want my query? Umm... OK... I though it is pretty obvious, but - here it is:
with
UserTbl as -- Selects an employee and his subordinates.
(
select a.[User_ID], a.[Manager_ID] from [User] a WHERE [User_ID] = #UserID
union all
select a.[User_ID], a.[Manager_ID] from [User] a join UserTbl b on (a.[Manager_ID]=b.[User_ID])
)
select * from UserTbl
Added 2: Oh, in case it wasn't clear - this is a production system and I have to do a little upgrade (basically add a sort of report). Thus, I'd prefer not to modify the data if it can be avoided.
I know it has been a while but thought I should share my experience as I tried every single solution and here is a summary of my findings (an maybe this post?):
Adding a column with the current path did work but had a performance hit so not an option for me.
I could not find a way to do it using CTE.
I wrote a recursive SQL function which adds employeeIds to a table. To get around the circular referencing, there is a check to make sure no duplicate IDs are added to the table. The performance was average but was not desirable.
Having done all of that, I came up with the idea of dumping the whole subset of [eligible] employees to code (C#) and filter them there using a recursive method. Then I wrote the filtered list of employees to a datatable and export it to my stored procedure as a temp table. To my disbelief, this proved to be the fastest and most flexible method for both small and relatively large tables (I tried tables of up to 35,000 rows).
this will work for the initial recursive link, but might not work for longer links
DECLARE #Table TABLE(
ID INT,
PARENTID INT
)
INSERT INTO #Table (ID,PARENTID) SELECT 1, 2
INSERT INTO #Table (ID,PARENTID) SELECT 2, 1
INSERT INTO #Table (ID,PARENTID) SELECT 3, 1
INSERT INTO #Table (ID,PARENTID) SELECT 4, 3
INSERT INTO #Table (ID,PARENTID) SELECT 5, 2
SELECT * FROM #Table
DECLARE #ID INT
SELECT #ID = 1
;WITH boss (ID,PARENTID) AS (
SELECT ID,
PARENTID
FROM #Table
WHERE PARENTID = #ID
),
bossChild (ID,PARENTID) AS (
SELECT ID,
PARENTID
FROM boss
UNION ALL
SELECT t.ID,
t.PARENTID
FROM #Table t INNER JOIN
bossChild b ON t.PARENTID = b.ID
WHERE t.ID NOT IN (SELECT PARENTID FROM boss)
)
SELECT *
FROM bossChild
OPTION (MAXRECURSION 0)
what i would recomend is to use a while loop, and only insert links into temp table if the id does not already exist, thus removing endless loops.
Not a generic solution, but might work for your case: in your select query modify this:
select a.[User_ID], a.[Manager_ID] from [User] a join UserTbl b on (a.[Manager_ID]=b.[User_ID])
to become:
select a.[User_ID], a.[Manager_ID] from [User] a join UserTbl b on (a.[Manager_ID]=b.[User_ID])
and a.[User_ID] <> #UserID
You don't have to do it recursively. It can be done in a WHILE loop. I guarantee it will be quicker: well it has been for me every time I've done timings on the two techniques. This sounds inefficient but it isn't since the number of loops is the recursion level. At each iteration you can check for looping and correct where it happens. You can also put a constraint on the temporary table to fire an error if looping occurs, though you seem to prefer something that deals with looping more elegantly. You can also trigger an error when the while loop iterates over a certain number of levels (to catch an undetected loop? - oh boy, it sometimes happens.
The trick is to insert repeatedly into a temporary table (which is primed with the root entries), including a column with the current iteration number, and doing an inner join between the most recent results in the temporary table and the child entries in the original table. Just break out of the loop when ##rowcount=0!
Simple eh?
I know you asked this question a while ago, but here is a solution that may work for detecting infinite recursive loops. I generate a path and I checked in the CTE condition if the USER ID is in the path, and if it is it wont process it again. Hope this helps.
Jose
DECLARE #Table TABLE(
USER_ID INT,
MANAGER_ID INT )
INSERT INTO #Table (USER_ID,MANAGER_ID) SELECT 1, 2
INSERT INTO #Table (USER_ID,MANAGER_ID) SELECT 2, 1
INSERT INTO #Table (USER_ID,MANAGER_ID) SELECT 3, 1
INSERT INTO #Table (USER_ID,MANAGER_ID) SELECT 4, 3
INSERT INTO #Table (USER_ID,MANAGER_ID) SELECT 5, 2
DECLARE #UserID INT
SELECT #UserID = 1
;with
UserTbl as -- Selects an employee and his subordinates.
(
select
'/'+cast( a.USER_ID as varchar(max)) as [path],
a.[User_ID],
a.[Manager_ID]
from #Table a
where [User_ID] = #UserID
union all
select
b.[path] +'/'+ cast( a.USER_ID as varchar(max)) as [path],
a.[User_ID],
a.[Manager_ID]
from #Table a
inner join UserTbl b
on (a.[Manager_ID]=b.[User_ID])
where charindex('/'+cast( a.USER_ID as varchar(max))+'/',[path]) = 0
)
select * from UserTbl
basicaly if you have loops like this in data you'll have to do the retreival logic by yourself.
you could use one cte to get only subordinates and other to get bosses.
another idea is to have a dummy row as a boss to both company owners so they wouldn't be each others bosses which is ridiculous. this is my prefferd option.
I can think of two approaches.
1) Produce more rows than you want, but include a check to make sure it does not recurse too deep. Then remove duplicate User records.
2) Use a string to hold the Users already visited. Like the not in subquery idea that didn't work.
Approach 1:
; with TooMuchHierarchy as (
select "User_ID"
, Manager_ID
, 0 as Depth
from "User"
WHERE "User_ID" = #UserID
union all
select U."User_ID"
, U.Manager_ID
, M.Depth + 1 as Depth
from TooMuchHierarchy M
inner join "User" U
on U.Manager_ID = M."user_id"
where Depth < 100) -- Warning MAGIC NUMBER!!
, AddMaxDepth as (
select "User_ID"
, Manager_id
, Depth
, max(depth) over (partition by "User_ID") as MaxDepth
from TooMuchHierarchy)
select "user_id", Manager_Id
from AddMaxDepth
where Depth = MaxDepth
The line where Depth < 100 is what keeps you from getting the max recursion error. Make this number smaller, and less records will be produced that need to be thrown away. Make it too small and employees won't be returned, so make sure it is at least as large as the depth of the org chart being stored. Bit of a maintence nightmare as the company grows. If it needs to be bigger, then add option (maxrecursion ... number ...) to whole thing to allow more recursion.
Approach 2:
; with Hierarchy as (
select "User_ID"
, Manager_ID
, '#' + cast("user_id" as varchar(max)) + '#' as user_id_list
from "User"
WHERE "User_ID" = #UserID
union all
select U."User_ID"
, U.Manager_ID
, M.user_id_list + '#' + cast(U."user_id" as varchar(max)) + '#' as user_id_list
from Hierarchy M
inner join "User" U
on U.Manager_ID = M."user_id"
where user_id_list not like '%#' + cast(U."User_id" as varchar(max)) + '#%')
select "user_id", Manager_Id
from Hierarchy
The preferrable solution is to clean up the data and to make sure you do not have any loops in the future - that can be accomplished with a trigger or a UDF wrapped in a check constraint.
However, you can use a multi statement UDF as I demonstrated here: Avoiding infinite loops. Part One
You can add a NOT IN() clause in the join to filter out the cycles.
This is the code I used on a project to chase up and down hierarchical relationship trees.
User defined function to capture subordinates:
CREATE FUNCTION fn_UserSubordinates(#User_ID INT)
RETURNS #SubordinateUsers TABLE (User_ID INT, Distance INT) AS BEGIN
IF #User_ID IS NULL
RETURN
INSERT INTO #SubordinateUsers (User_ID, Distance) VALUES ( #User_ID, 0)
DECLARE #Distance INT, #Finished BIT
SELECT #Distance = 1, #Finished = 0
WHILE #Finished = 0
BEGIN
INSERT INTO #SubordinateUsers
SELECT S.User_ID, #Distance
FROM Users AS S
JOIN #SubordinateUsers AS C
ON C.User_ID = S.Manager_ID
LEFT JOIN #SubordinateUsers AS C2
ON C2.User_ID = S.User_ID
WHERE C2.User_ID IS NULL
IF ##RowCount = 0
SET #Finished = 1
SET #Distance = #Distance + 1
END
RETURN
END
User defined function to capture managers:
CREATE FUNCTION fn_UserManagers(#User_ID INT)
RETURNS #User TABLE (User_ID INT, Distance INT) AS BEGIN
IF #User_ID IS NULL
RETURN
DECLARE #Manager_ID INT
SELECT #Manager_ID = Manager_ID
FROM UserClasses WITH (NOLOCK)
WHERE User_ID = #User_ID
INSERT INTO #UserClasses (User_ID, Distance)
SELECT User_ID, Distance + 1
FROM dbo.fn_UserManagers(#Manager_ID)
INSERT INTO #User (User_ID, Distance) VALUES (#User_ID, 0)
RETURN
END
You need a some method to prevent your recursive query from adding User ID's already in the set. However, as sub-queries and double mentions of the recursive table are not allowed (thank you van) you need another solution to remove the users already in the list.
The solution is to use EXCEPT to remove these rows. This should work according to the manual. Multiple recursive statements linked with union-type operators are allowed. Removing the users already in the list means that after a certain number of iterations the recursive result set returns empty and the recursion stops.
with UserTbl as -- Selects an employee and his subordinates.
(
select a.[User_ID], a.[Manager_ID] from [User] a WHERE [User_ID] = #UserID
union all
(
select a.[User_ID], a.[Manager_ID]
from [User] a join UserTbl b on (a.[Manager_ID]=b.[User_ID])
where a.[User_ID] not in (select [User_ID] from UserTbl)
EXCEPT
select a.[User_ID], a.[Manager_ID] from UserTbl a
)
)
select * from UserTbl;
The other option is to hardcode a level variable that will stop the query after a fixed number of iterations or use the MAXRECURSION query option hint, but I guess that is not what you want.