computation and promutation

i am trying to set up a quick and dirty, but efficient way to calculate permutation and combination. anyone out there dealt with this?any takers?|||The method depends on what kind of permutations you want to do.

Given N objects in X different positions, do you want to allow repetitions? Do you want to include permutations with less than X values?

There are formulas available that will calculate these. Excel actually has some good statistical functions that not only do the calculations, but the help file does a good job of explaining the formula used. You might run a couple test on a spreadsheet until you are sure what kind of permutation you want, and then port the formula from Excel's help file into a TSQL statement.|||ok, it's been awhile, and i barely passed it, but knowing the total number (9999), what is the n in this combination formula:

9999 = n! / (4!(n-4)!)|||never mind, it doesn't jive, back to the drawing board|||N is the number of items, and I believe 4 is the number of locations.

N! is N Factorial, which SQL Server does not have as a standard function, but is simply 1*2*3*4*5...*N, so you could write the function easily enough.|||...and 9999 factorial would be HUGE! We're way beyond "grains of sand" and into "atoms in the universe" here...

Composite key "NOT IN" query?

I have a table with a composite key formed by the unique combination of columns w, x, y, z

I'm trying to write an INSERT statement along the following lines

INSERT INTO myTable

(SELECT w, x, y, z FROM someTable) t1

WHERE (this is the part I'm stumped on - where the unique combination of w, x, y, z is NOT in myTable already)

Help would be appreciated. Can you use the NOT IN keyword on composite values?

Can you use the NOT IN keyword on composite values?

Yes,but that is expensive.

FromQuery SQL Server Performance Tuning Tips

But If you currently have a query that uses NOT IN, which offers poor performance because the SQL Server optimizer has to use a nested table scan to perform this activity, instead try to use one of the following options instead, all of which offer better performance:

Use EXISTS or NOT EXISTS|||

INSERT INTO MyTable

SELECT t1.w,t1.x,t1.y,t1.z

FROM someTable t1

LEFT JOIN MyTable t2 ON t1.w=t2.w and t1.x=t2.x and t1.y=t2.y and t1.z=t2.z

WHERE t2.w IS NULL

This should also work:

INSERT INTO MyTable

SELECT w,x,y,z

FROM someTable

EXCEPT

SELECT w,x,y,z

FROM MyTable

Composite FK

You can have a composite PK but can you have a composite FK?
I want to make sure that the combination orderid and custid in
"orderhistory" table is always the same as a combination of orderid custid
in the "orders" table.
What's the best way to do this? Can I do something with a FK to enforece
this? Or do I need to use a trigger?Not a problem:
create table MyTable
(
id int primary key
, orderid int not null
, custid int not null
, foreign key FK1_MyTable references MyOtherTable (orderid, custid)
)
Tom
---
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA
SQL Server MVP
Columnist, SQL Server Professional
Toronto, ON Canada
www.pinnaclepublishing.com/sql
"Dave" <dave@.nodomain.tv> wrote in message
news:eVje8kcEEHA.624@.TK2MSFTNGP10.phx.gbl...
You can have a composite PK but can you have a composite FK?
I want to make sure that the combination orderid and custid in
"orderhistory" table is always the same as a combination of orderid custid
in the "orders" table.
What's the best way to do this? Can I do something with a FK to enforece
this? Or do I need to use a trigger?|||Absolutely. First you need to ensure that the "parent" table has its primary
key defined as (orderid, custid). Once the primary key is in place, the DDL
to create your FK might look something like:
alter table foo add constraint foo_fk foreign key (orderid, custid)
references parenttable (orderid, custid)
--Brian
(Please reply to the newsgroups only.)
"Dave" <dave@.nodomain.tv> wrote in message
news:eVje8kcEEHA.624@.TK2MSFTNGP10.phx.gbl...
> You can have a composite PK but can you have a composite FK?
> I want to make sure that the combination orderid and custid in
> "orderhistory" table is always the same as a combination of orderid custid
> in the "orders" table.
> What's the best way to do this? Can I do something with a FK to enforece
> this? Or do I need to use a trigger?
>
>
>|||Thanks guys for the prompt and useful info.
"Dave" <dave@.nodomain.tv> wrote in message
news:eVje8kcEEHA.624@.TK2MSFTNGP10.phx.gbl...
> You can have a composite PK but can you have a composite FK?
> I want to make sure that the combination orderid and custid in
> "orderhistory" table is always the same as a combination of orderid custid
> in the "orders" table.
> What's the best way to do this? Can I do something with a FK to enforece
> this? Or do I need to use a trigger?
>
>
>

Complex variable length string combination problem

Hi,
I'm having trouble finding a solution for the following problem:
Suppose you have the following string as input 'sig, ltw, onss'
I would like to generate the following result set:
sig
ltw
onss
sig, ltw
sig, onss
ltw, onns
sig, ltw, onss
This should also work for any number of names (each time seperated by a
comma) within the string ex.:
input = 'sig, ltw, onss, plk'
output =
sig
ltw
onss
plk
sig, ltw
sig, onss
sig, plk
ltw, onns
ltw, plk
onss, plk
sig, ltw, onss
sig, onss, plk
ltw, onss, plk
sig, ltw, onss, plk
Anyone an idea how to resolve this problem?
Thanx in advance...Why don't you put this data in a table rather than a delimited string? TSQL
really isn't a language for string manipulation and delimited data just
shouldn't exist in the database.
The permutations you want to output could be achieved with a self- CROSS
JOIN once you've put the data in a table.
David Portas
SQL Server MVP
--|||You can also do it with the ROLLUP operator:
CREATE TABLE foo (x VARCHAR(5) PRIMARY KEY)
INSERT INTO foo VALUES ('sig')
INSERT INTO foo VALUES ('ltw')
INSERT INTO foo VALUES ('onss')
SELECT A.x, B.x, C.x
FROM foo AS A
JOIN foo AS B
ON B.x <> A.x
JOIN foo AS C
ON C.x <> A.x
AND C.x <> B.x
GROUP BY A.x, B.x, C.x WITH ROLLUP
David Portas
SQL Server MVP
--|||Hi,
I agree that string manipulation is not so easy in T-SQL.
Suppose I put the words as rows in a table; the problem with the crossjoin
is that it returns too many possiblities that are not usefull to me:
given a, b, c
the crossjoin would generate:
a, a, a
a, b, a
a, c, a
b, a, a => already exists but in another order
etc...
As you see whereas in my case I generate 14 possibilities for a 4 names
comma seperated string in your case this will be 27 possibilities; in other
words almost twice as many.
A solution would be to elimate from the crossjoin result the same occurences
of the names but in another order. But how?
"David Portas" wrote:

> Why don't you put this data in a table rather than a delimited string? TSQ
L
> really isn't a language for string manipulation and delimited data just
> shouldn't exist in the database.
> The permutations you want to output could be achieved with a self- CROSS
> JOIN once you've put the data in a table.
> --
> David Portas
> SQL Server MVP
> --|||This is pretty close; if we could just eliminate the "doubles" (in this case
the same names but in a different order) than I would be a happy man... ;-)
"David Portas" wrote:

> You can also do it with the ROLLUP operator:
> CREATE TABLE foo (x VARCHAR(5) PRIMARY KEY)
> INSERT INTO foo VALUES ('sig')
> INSERT INTO foo VALUES ('ltw')
> INSERT INTO foo VALUES ('onss')
> SELECT A.x, B.x, C.x
> FROM foo AS A
> JOIN foo AS B
> ON B.x <> A.x
> JOIN foo AS C
> ON C.x <> A.x
> AND C.x <> B.x
> GROUP BY A.x, B.x, C.x WITH ROLLUP
> --
> David Portas
> SQL Server MVP
> --
>|||Try this one then:
CREATE TABLE foo (x VARCHAR(5) PRIMARY KEY)
INSERT INTO foo VALUES ('sig')
INSERT INTO foo VALUES ('ltw')
INSERT INTO foo VALUES ('onss')
INSERT INTO foo VALUES ('')
SELECT A.x, NULLIF(B.x,''), NULLIF(C.x,'')
FROM foo AS A
LEFT JOIN foo AS B
ON B.x < A.x
LEFT JOIN foo AS C
ON C.x < B.x
WHERE A.x > ''
David Portas
SQL Server MVP
--|||David,
Great!!!! this is exactly what I need.
Is there an easy way to make this code dynamic as to receive any number of
input rows?
This already is great to work on...
thanx man! :-)
"David Portas" wrote:

> Try this one then:
> CREATE TABLE foo (x VARCHAR(5) PRIMARY KEY)
> INSERT INTO foo VALUES ('sig')
> INSERT INTO foo VALUES ('ltw')
> INSERT INTO foo VALUES ('onss')
> INSERT INTO foo VALUES ('')
> SELECT A.x, NULLIF(B.x,''), NULLIF(C.x,'')
> FROM foo AS A
> LEFT JOIN foo AS B
> ON B.x < A.x
> LEFT JOIN foo AS C
> ON C.x < B.x
> WHERE A.x > ''
> --
> David Portas
> SQL Server MVP
> --
>|||The following is really slow, (cause it's resursive), but it works...
First step would be to get the Indiv Strings into a table.. You can use the
following function for that... It's a generally useful function to have
around anyway...
Create Function dbo.ParseString (
@.S VarChar(8000),
@.delim Char(1))
Returns @.tOut Table (ValNum Integer Primary Key Identity, sVal VarChar(500)
)
As
Begin
Declare @.sVal VarChar(80)
Declare @.deLimPos Integer
If right(@.S,1) <> @.Delim Set @.S = @.S + @.Delim
While Len(@.S) > 0
Begin
Set @.deLimPos = CharIndex(@.delim, @.S)
Set @.sVal = Left(@.S,@.deLimPos -1)
Set @.S = Right(@.S,Len(@.S) - @.deLimPos)
Insert @.tOut (sVal) Values (@.sVal)
End
Return
End
-- ----
This function parses a string, using the supplied delimiter, and returns a
table with one row for each entry in the string.
Next, you need a function to "alphabeticize" a delimited string... This one
does the trick...
Create FUNCTION dbo.SortString
(@.S VarChar(1000), @.Delim Char(1))
RETURNS VarChar(1000)
AS
BEGIN
Declare @.Out VarChar(1000) Set @.Out = ''
Declare @.Vals Table (Val VarChar(100))
Declare @.Val VarChar(100)
Insert @.Vals(Val)
Select LTrim(sVal)
From dbo.ParseString(@.S, @.Delim)
While Exists(Select * From @.Vals) Begin
Select @.Val = Min(Val) From @.Vals
Set @.Out = @.Out + @.Val + ','
Delete @.Vals Where Val = @.Val
End
Return Substring(@.Out, 1, Len(@.Out) -1)
END
-- ----
Using these 2 functions, you can dynamically do what you want wit hteh
following:
assuming the variable @.Input contains the original concatenated string...
Declare @.Input VarChar(100) Set @.Input = 'a, b, c'
Declare @.Items Table (ItmNo Integer Primary Key Identity, item varchar(50))
Declare @.Permutations Table(Permutation VarChar(1000))
Insert @.Items (Item)
Select sVal
From dbo.ParseString(@.Input , ',')
Order By sVal
-- ---
--Select * From @.Items
Declare @.NumItems TinyInt
Declare @.Size TinyInt Set @.Size = 0
Select @.NumItems = Count(*) From @.Items
While @.Size <= @.NumItems Begin
Insert @.Permutations (Permutation)
Select Distinct dbo.SortString(IsNull(P.Permutation + ', ', '') +
I.Item, ',')
From @.Items I Left Join @.Permutations P
On I.Item <> IsNull(P.Permutation,'')
Where Not Exists(Select * From @.Permutations
Where Permutation =
dbo.SortString(IsNull(P.Permutation + ', ', '') +
I.Item, ','))
And CharIndex(I.Item, IsNull(P.Permutation,'')) = 0
Set @.Size = @.Size + 1
End
Insert @.Permutations(Permutation) Values('')
Select * From @.Permutations|||Thanks man for your effort.
Will stick to the answer of David Portas found it very elegant.
"CBretana" wrote:

> The following is really slow, (cause it's resursive), but it works...
> First step would be to get the Indiv Strings into a table.. You can use th
e
> following function for that... It's a generally useful function to have
> around anyway...
> Create Function dbo.ParseString (
> @.S VarChar(8000),
> @.delim Char(1))
> Returns @.tOut Table (ValNum Integer Primary Key Identity, sVal VarChar(50
0))
> As
> Begin
> Declare @.sVal VarChar(80)
> Declare @.deLimPos Integer
> If right(@.S,1) <> @.Delim Set @.S = @.S + @.Delim
> While Len(@.S) > 0
> Begin
> Set @.deLimPos = CharIndex(@.delim, @.S)
> Set @.sVal = Left(@.S,@.deLimPos -1)
> Set @.S = Right(@.S,Len(@.S) - @.deLimPos)
> Insert @.tOut (sVal) Values (@.sVal)
> End
> Return
> End
> -- ----
> This function parses a string, using the supplied delimiter, and returns a
> table with one row for each entry in the string.
> Next, you need a function to "alphabeticize" a delimited string... This on
e
> does the trick...
> Create FUNCTION dbo.SortString
> (@.S VarChar(1000), @.Delim Char(1))
> RETURNS VarChar(1000)
> AS
> BEGIN
> Declare @.Out VarChar(1000) Set @.Out = ''
> Declare @.Vals Table (Val VarChar(100))
> Declare @.Val VarChar(100)
> Insert @.Vals(Val)
> Select LTrim(sVal)
> From dbo.ParseString(@.S, @.Delim)
> While Exists(Select * From @.Vals) Begin
> Select @.Val = Min(Val) From @.Vals
> Set @.Out = @.Out + @.Val + ','
> Delete @.Vals Where Val = @.Val
> End
> Return Substring(@.Out, 1, Len(@.Out) -1)
> END
> -- ----
> Using these 2 functions, you can dynamically do what you want wit hteh
> following:
> assuming the variable @.Input contains the original concatenated string...
> Declare @.Input VarChar(100) Set @.Input = 'a, b, c'
> Declare @.Items Table (ItmNo Integer Primary Key Identity, item varchar(50)
)
> Declare @.Permutations Table(Permutation VarChar(1000))
> Insert @.Items (Item)
> Select sVal
> From dbo.ParseString(@.Input , ',')
> Order By sVal
> -- ---
> --Select * From @.Items
> Declare @.NumItems TinyInt
> Declare @.Size TinyInt Set @.Size = 0
> Select @.NumItems = Count(*) From @.Items
>
> While @.Size <= @.NumItems Begin
> Insert @.Permutations (Permutation)
> Select Distinct dbo.SortString(IsNull(P.Permutation + ', ', '') +
> I.Item, ',')
> From @.Items I Left Join @.Permutations P
> On I.Item <> IsNull(P.Permutation,'')
> Where Not Exists(Select * From @.Permutations
> Where Permutation =
> dbo.SortString(IsNull(P.Permutation + ', ', '')
+
> I.Item, ','))
> And CharIndex(I.Item, IsNull(P.Permutation,'')) = 0
> Set @.Size = @.Size + 1
> End
> Insert @.Permutations(Permutation) Values('')
> Select * From @.Permutations
>|||No problemo Peter,
David's solution is much more elegant, and much faster, but as you noticed,
it not dynamic as to the number of items in the imput string...
But as I'm sure you have already figured out, the required processing to
solve this problem increases very very fast as the number of items increases
.
Regards,
Charly
"PeterM" wrote:
> Thanks man for your effort.
> Will stick to the answer of David Portas found it very elegant.
> "CBretana" wrote:
>