nested joins - joining one table to another multiple times

Hi,

I'm having problems constructing a nested join. It's quite complex, so
here's a simplfied example of the problem. Any thoughts on what I'm
doig wrong - or if I've got the whole approach wrong are welcome.

I've two tables :-

one is a contact table contacting name, addresses etc. Three of the
fields represent users - 'created by', 'last modified by' and 'owner'.
They contain usernames - eg. JDOE, BSMITH etc.

The other table contants usernames and new ID codes.

What I want to do is create a new dataset by joining the contacts table
with the user table on all three fields - so the new dataset contains
the ids for the creator, last modifier and owner.

I've tried things similar to:

select c.*, u1.id, u2,id, u3.id
from contact c
left outer join users u1
left outer join users u2
left outer join users u3
on (u3.username = c.owner)
on (u2.username = c.modified)
on (u1.username = c.creator )

But it compains that
"The column prefix 'c' does not match with a table name or alias name
used in the query."

The problem is referencing c (contact) through the whole set of joins.

I would like to do this in some similar format as the query is within a
cursor and post-processing would be very long-winded.

ThanksHi Steve,

this sql-code will work:

select c.*, u1.id, u2.id, u3.id
from contact c
left outer join users u1 ON u1.username = c.creator
left outer join users u2 ON u2.username = c.modified
left outer join users u3 ON u3.username = c.owner

Steve C schrieb:
...
> select c.*, u1.id, u2,id, u3.id
> from contact c
> left outer join users u1
> left outer join users u2
> left outer join users u3
> on (u3.username = c.owner)
> on (u2.username = c.modified)
> on (u1.username = c.creator )
> But it compains that
> "The column prefix 'c' does not match with a table name or alias name
> used in the query."

www.zankl-it.de

Nested Filters

Is it possible to create a complex, nested filter on a table in a report?
For example:
(Statement A AND Statement B) OR (Statement C AND Statement D)Hello Cindy,
Based on my experience, you could done this in another approach:
In the Filter of a table in reporting services, you type the nested filter
in the expression like this:
IIF( (Statement A AND Statement B) OR (Statement C AND Statement D) ,0,1)
Then, if the whole statement is true, the expression will return 0, and if
false, return 1.
Then, you could add "=0" (without quote) in the value column of the filter.
Hope this will be helpful!
Sincerely,
Wei Lu
Microsoft Online Community Support
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assistance.
Sincerely,
Wei Lu
Microsoft Online Community Support
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need to write complex query without cursor

Hi all,
I am trying to do the following and am getting stuck.Your help wil be higly
appreciated.
I am matching two tables.If i get a single matching row then get that single
row
but if i get >1 matching rows i should select only the one with the latest
date.
for example
Table1
--
id value
1 10
2 20
3 30
Table 2
--
id param updateDate
1 10 day1
1 20 day2
1 25 day3
2 20 day2
2 40 day 3
3 30 day 2
(day1 <day2<day3 etc)
So i should get results as
Result
--
1 25 day3
2 40 day3
3 30 day2
how can I do this without a cursor?
Thanks for your help.on SQL 2005,
select id, param, updateDate
from table2
where row_number() over(partition by id order by updateDate desc) = 1
*untested*|||Try this, if you don't have SQL Server 2005:
select Table2.id, Table2.param, Table2.updateDate
from Table2
join Table1 on Table1.id = Table2.id
where updateDate = (
select max(updateDate) from Table2 as T_copy
where T_copy = Table2.id
)
or
select id, param, updateDate
from Table2
where updateDate = (
select max(updateDate) from Table2 as T_copy
where T_copy = Table2.id
) and exists (
select * from Table1
where Table1.id = Table2.id
)
This can yield multiple rows per id if (id, updateDate) is not unique
and there are two or more updates for an id on most recent update date.
For SQL Server 2005, Alexander has the right idea, but windowed
functions cannot appear in the WHERE clause, and you'll have to do this:
select id, param, updateDate
from (
select
id, param, updateDate,
row_number() over (partition by id order by updateDate desc) as rn
from Table2
) as T
where rn = 1
Steve Kass
Drew University
tech77 wrote:

>Hi all,
>I am trying to do the following and am getting stuck.Your help wil be higly
>appreciated.
>I am matching two tables.If i get a single matching row then get that singl
e
>row
> but if i get >1 matching rows i should select only the one with the latest
>date.
>for example
>Table1
>--
>id value
>1 10
>2 20
>3 30
>Table 2
>--
>id param updateDate
>1 10 day1
>1 20 day2
>1 25 day3
>2 20 day2
>2 40 day 3
>3 30 day 2
>(day1 <day2<day3 etc)
>So i should get results as
>Result
>--
>1 25 day3
>2 40 day3
>3 30 day2
>how can I do this without a cursor?
>Thanks for your help.
>|||Here's one method, assuming that each id will only have one row per
day. If you have multiple rows per id per day, you have to have some
rule to determine which row you want returned.
Stu
DECLARE @.Table1 TABLE (id int, value int)
INSERT INTO @.TABLE1
SELECT 1, 10
UNION ALL
SELECT 2, 20
UNION ALL
SELECT 3, 30
DECLARE @.Table2 TABLE (id int, param int, UpdateDate smalldatetime)
INSERT INTO @.TABLE2
SELECT 1, 10, '20060301'
UNION ALL
SELECT 1, 20, '20060302'
UNION ALL
SELECT 1, 25, '20060303'
UNION ALL
SELECT 2, 20, '20060302'
UNION ALL
SELECT 2, 40, '20060303'
UNION ALL
SELECT 3, 30, '20060302'
SELECT t2.id, t2.param, t2.UpdateDate
FROM @.table1 t1 JOIN @.Table2 t2 ON t1.id=t2.id
JOIN (SELECT id, MAX(updateDate) AS upDateDate
FROM @.Table2 t2
GROUP BY id) t2_2 ON t2.ID = t2_2.ID
AND t2.UpDateDate = t2_2.UpdateDate