Inner Join experts out there??

[news-east.earthlink.net]

The scenario:

two tables

CustomerTable
---------------
CustomerID
OrderID
CustomerName
CustomerEmail
CustomerPhone

OrderTable
---------------
OrderID
ProductID
ProductName
ProductCost

This database was handed to me and I was asked to solve a problem - it looks
like an inner join solution would apply, but I'm not 100% sure.

There are 14 products total (numbers 1 through 14).
I'm looking to get a list of all the customers who have ordered product #1,
UNLESS they've ordered product #14 in which case I don't want to know about
that customer at all.

Any help would be greatly appreciated! I'll watch the newsgroup for the
answer - hopefully your response can help someone else too. However, if you
prefer to email me directly, you can send it to me at bunchah at yahoo dot
com.

Thanks in advance!

(if it'll help, I'll buy the person offering the correct solution a beer -
pending age verification of course) ;)

-Al

[Andy Hassall]

On Sat, 22 Nov 2003 00:52:35 GMT, "news-east.earthlink. net"
<ab************ ******@yahoo.no spam.com> wrote:

The scenario:

two tables

CustomerTabl e
---------------
CustomerID
OrderID
CustomerName
CustomerEmai l
CustomerPhon e

OrderTable
---------------
OrderID
ProductID
ProductName
ProductCost

This database was handed to me and I was asked to solve a problem - it looks
like an inner join solution would apply, but I'm not 100% sure.

There are 14 products total (numbers 1 through 14).
I'm looking to get a list of all the customers who have ordered product #1,
UNLESS they've ordered product #14 in which case I don't want to know about
that customer at all.

A literal translation could be:

SELECT DISTINCT CustomerID
FROM CustomerTable
WHERE CustomerID IN (SELECT CustomerID
FROM OrderTable
WHERE ProductID = 1)
AND CustomerID NOT IN (SELECT CustomerID
FROM OrderTable
WHERE ProductID = 14)

Or:

SELECT CustomerID
FROM CustomerTable
INNER JOIN OrderTable USING (OrderID)
WHERE ProductID = 1
MINUS
SELECT CustomerID
FROM CustomerTable
INNER JOIN OrderTable USING (OrderID)
WHERE ProductID = 14

--
Andy Hassall (an**@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)

[Dave Hau]

select ct.customerid
from CustomerTable ct
join OrderTable ot
on ct.orderid = ot.orderid
group by ct.customerid
having (count(case ot.productid when 1 then 1 else null end) > 0)
and (count(case ot.productid when 14 then 1 else null end) = 0)
order by ct.customerid
HTH,
Dave

"news-east.earthlink. net" <ab************ ******@yahoo.no spam.com> wrote in
message news:nr******** **********@news read2.news.atl. earthlink.net.. .

The scenario:

two tables

CustomerTable
---------------
CustomerID
OrderID
CustomerName
CustomerEmail
CustomerPhone

OrderTable
---------------
OrderID
ProductID
ProductName
ProductCost

This database was handed to me and I was asked to solve a problem - it looks like an inner join solution would apply, but I'm not 100% sure.

There are 14 products total (numbers 1 through 14).
I'm looking to get a list of all the customers who have ordered product #1, UNLESS they've ordered product #14 in which case I don't want to know about that customer at all.

Any help would be greatly appreciated! I'll watch the newsgroup for the
answer - hopefully your response can help someone else too. However, if you prefer to email me directly, you can send it to me at bunchah at yahoo dot
com.

Thanks in advance!

(if it'll help, I'll buy the person offering the correct solution a beer -
pending age verification of course) ;)

-Al

[Dave Hau]

"Andy Hassall" <an**@andyh.co. uk> wrote in message
news:t5******** *************** *********@4ax.c om...

On Sat, 22 Nov 2003 00:52:35 GMT, "news-east.earthlink. net"
<ab************ ******@yahoo.no spam.com> wrote:

The scenario:

two tables

CustomerTabl e
---------------
CustomerID
OrderID
CustomerName
CustomerEmai l
CustomerPhon e

OrderTable
---------------
OrderID
ProductID
ProductName
ProductCost

This database was handed to me and I was asked to solve a problem - it lookslike an inner join solution would apply, but I'm not 100% sure.

There are 14 products total (numbers 1 through 14).
I'm looking to get a list of all the customers who have ordered product #1,UNLESS they've ordered product #14 in which case I don't want to know aboutthat customer at all.
A literal translation could be:

SELECT DISTINCT CustomerID
FROM CustomerTable
WHERE CustomerID IN (SELECT CustomerID
FROM OrderTable
WHERE ProductID = 1)
AND CustomerID NOT IN (SELECT CustomerID
FROM OrderTable
WHERE ProductID = 14)

Or:

SELECT CustomerID
FROM CustomerTable
INNER JOIN OrderTable USING (OrderID)
WHERE ProductID = 1
MINUS
SELECT CustomerID
FROM CustomerTable
INNER JOIN OrderTable USING (OrderID)
WHERE ProductID = 14

Andy, I don't think the second solution will work. First of all, MINUS is
not supported on SQL Server. Second, even if this is run on Oracle, the two
result sets you're performing the minus on are the joined tables, not the
single table CustomerTable. So the two sets are disjoint because ProductID
cannot be 1 and 14 simultaneously. So you'll end up with all the customers
who have ordered product #1, regardless of whether they have ordered product
#14 or not.

Since there's a beer involved here, I have to be a bit particular... ;-)

- Dave


--
Andy Hassall (an**@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)

[Dave Hau]

"Dave Hau" <nospam_dave_no spam_123@nospam _netscape_nospa m.net_nospam> wrote
in message news:r%******** ***********@new ssvr27.news.pro digy.com...

"Andy Hassall" <an**@andyh.co. uk> wrote in message
news:t5******** *************** *********@4ax.c om...

On Sat, 22 Nov 2003 00:52:35 GMT, "news-east.earthlink. net"
<ab************ ******@yahoo.no spam.com> wrote:

The scenario:

two tables

CustomerTabl e
---------------
CustomerID
OrderID
CustomerName
CustomerEmai l
CustomerPhon e

OrderTable
---------------
OrderID
ProductID
ProductName
ProductCost

This database was handed to me and I was asked to solve a problem - it lookslike an inner join solution would apply, but I'm not 100% sure.

There are 14 products total (numbers 1 through 14).
I'm looking to get a list of all the customers who have ordered product #1,UNLESS they've ordered product #14 in which case I don't want to know aboutthat customer at all.
A literal translation could be:

SELECT DISTINCT CustomerID
FROM CustomerTable
WHERE CustomerID IN (SELECT CustomerID
FROM OrderTable
WHERE ProductID = 1)
AND CustomerID NOT IN (SELECT CustomerID
FROM OrderTable
WHERE ProductID = 14)

Or:

SELECT CustomerID
FROM CustomerTable
INNER JOIN OrderTable USING (OrderID)
WHERE ProductID = 1
MINUS
SELECT CustomerID
FROM CustomerTable
INNER JOIN OrderTable USING (OrderID)
WHERE ProductID = 14

Andy, I don't think the second solution will work. First of all, MINUS is
not supported on SQL Server. Second, even if this is run on Oracle, the

two result sets you're performing the minus on are the joined tables, not the
single table CustomerTable. So the two sets are disjoint because ProductID cannot be 1 and 14 simultaneously. So you'll end up with all the customers who have ordered product #1, regardless of whether they have ordered product #14 or not.
Sorry didn't notice you're selecting only CustomerID instead of *. It does
work.

My bad. You won the beer. :)

- Dave

Since there's a beer involved here, I have to be a bit particular... ;-)

- Dave

--
Andy Hassall (an**@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)

[news-east.earthlink.net]

SELECT DISTINCT cart_id
FROM OrderTable
WHERE cart_id
IN (
SELECT cart_id
FROM CartTable
WHERE product_index =1 ) AND cart_id NOT
IN (
SELECT cart_id
FROM CartTable
WHERE product_index =14 )

After I switched the fields and table names out to match the real table
names ( they were confusing the issue a bit) I tried the quer(y/ies) and I
get errors on both.

Maybe I should clarify - this is running in a MySQL database server - though
with straight SQL I would think this wouldn't matter much, no?

I moved the structure of the actual tables to a database on my home server
and punched a hole in my firewall to allow you to look at this first hand -
mind you, there are only a few records and they're made up, but they should
be sufficient enough to let you tinker...

surf to http://maple.homelinux.com/phpmyadmin/index.php
account : aaron
pass: pass123

I'll leave it up and running this evening - the account has limited rights
(to that database only)...

take a gander?

BTW - for the speedy response, I'll buy both of you guys a beer...name your
poison!
"Andy Hassall" <an**@andyh.co. uk> wrote in message
news:t5******** *************** *********@4ax.c om...

On Sat, 22 Nov 2003 00:52:35 GMT, "news-east.earthlink. net"
<ab************ ******@yahoo.no spam.com> wrote:

The scenario:

two tables

CustomerTabl e
---------------
CustomerID
OrderID
CustomerName
CustomerEmai l
CustomerPhon e

OrderTable
---------------
OrderID
ProductID
ProductName
ProductCost

This database was handed to me and I was asked to solve a problem - it lookslike an inner join solution would apply, but I'm not 100% sure.

There are 14 products total (numbers 1 through 14).
I'm looking to get a list of all the customers who have ordered product #1,UNLESS they've ordered product #14 in which case I don't want to know aboutthat customer at all.

A literal translation could be:

SELECT DISTINCT CustomerID
FROM CustomerTable
WHERE CustomerID IN (SELECT CustomerID
FROM OrderTable
WHERE ProductID = 1)
AND CustomerID NOT IN (SELECT CustomerID
FROM OrderTable
WHERE ProductID = 14)

Or:

SELECT CustomerID
FROM CustomerTable
INNER JOIN OrderTable USING (OrderID)
WHERE ProductID = 1
MINUS
SELECT CustomerID
FROM CustomerTable
INNER JOIN OrderTable USING (OrderID)
WHERE ProductID = 14

--
Andy Hassall (an**@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)

[Andy Hassall]

On Sat, 22 Nov 2003 01:50:17 GMT, "news-east.earthlink. net"
<ab************ ******@yahoo.no spam.com> wrote:

Newsgroups: alt.php.sql,com p.databases.ms-sqlserver,micro soft.public.sql server.datamini ng

SELECT DISTINCT cart_id
FROM OrderTable
WHERE cart_id
IN (
SELECT cart_id
FROM CartTable
WHERE product_index =1 ) AND cart_id NOT
IN (
SELECT cart_id
FROM CartTable
WHERE product_index =14 )

After I switched the fields and table names out to match the real table
names ( they were confusing the issue a bit) I tried the quer(y/ies) and I
get errors on both.
What errors?
Maybe I should clarify - this is running in a MySQL database server - though
with straight SQL I would think this wouldn't matter much, no?
It makes a big difference - MySQL has large gaps in its SQL syntax - in
particular, no subqueries or set operations (i.e. MINUS).

(Subqueries are going into the alpha 4.1 version, I think UNION went into 4.0
at some point, don't know about MINUS).
I moved the structure of the actual tables to a database on my home server
and punched a hole in my firewall to allow you to look at this first hand -
mind you, there are only a few records and they're made up, but they should
be sufficient enough to let you tinker...

surf to http://maple.homelinux.com/phpmyadmin/index.php
account : aaron
pass: pass123

404 Object not found.

A variation on Dave's query to account for MySQL's limitations and quirks
(identifiers case-sensitive, cannot reference aggregates in HAVING clauses only
their aliases, JOIN must be INNER JOIN) comes up with:

select ct.CustomerID,
count(case ot.ProductID when 1 then 1 else null end) num_1,
count(case ot.ProductID when 14 then 1 else null end) num_14
from CustomerTable ct
inner join OrderTable ot
on (ct.OrderID = ot.OrderID)
group by ct.CustomerID
having num_1 > 0
and num_14 = 0
order by ct.CustomerID

This works against MySQL 3.x, 'cos I just ran it.

--
Andy Hassall (an**@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)

[Andy Hassall]

On Sat, 22 Nov 2003 02:06:15 +0000, Andy Hassall <an**@andyh.co. uk> wrote:

A variation on Dave's query to account for MySQL's limitations and quirks
[...] cannot reference aggregates in HAVING clauses only
their aliases, [...]

OK, that's wrong, looks like I was thinking of something else. So going closer
back to Dave's query:

select DISTINCT ct.CustomerID
from CustomerTable ct
inner join OrderTable ot
on (ct.OrderID = ot.OrderID)
group by ct.CustomerID
having count(case ot.ProductID when 1 then 1 else null end) > 0
and count(case ot.ProductID when 14 then 1 else null end) = 0
order by ct.CustomerID;

--
Andy Hassall (an**@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)

[Dave Hau]

"Andy Hassall" <an**@andyh.co. uk> wrote in message
news:du******** *************** *********@4ax.c om...

On Sat, 22 Nov 2003 02:06:15 +0000, Andy Hassall <an**@andyh.co. uk> wrote:

A variation on Dave's query to account for MySQL's limitations and quirks[...] cannot reference aggregates in HAVING clauses only
their aliases, [...]
OK, that's wrong, looks like I was thinking of something else. So going

closer back to Dave's query:

select DISTINCT ct.CustomerID
from CustomerTable ct
inner join OrderTable ot
on (ct.OrderID = ot.OrderID)
group by ct.CustomerID
having count(case ot.ProductID when 1 then 1 else null end) > 0
and count(case ot.ProductID when 14 then 1 else null end) = 0
order by ct.CustomerID;
IMHO, no need for the DISTINCT. The "group by ct.CustomerID" will always
give you distinct values of CustomerID.

- Dave


--
Andy Hassall (an**@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)

[Andy Hassall]

On Sat, 22 Nov 2003 02:23:14 GMT, "Dave Hau"
<nospam_dave_no spam_123@nospam _netscape_nospa m.net_nospam> wrote:

select DISTINCT ct.CustomerID [snip] group by ct.CustomerID

[snip]
IMHO, no need for the DISTINCT. The "group by ct.CustomerID" will always
give you distinct values of CustomerID.

Ah, yes - that's true.

--
Andy Hassall (an**@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)