My question is this: Is it possible to output multiple rows when joining from the same table?
With this code for example, I would like it to output 2 rows, one for each table. Instead, what it does is gives me 1 row with all of the data.
SELECT t1.*, t2.*
FROM table t1
JOIN table t2
ON t2.id = t1.oldId
WHERE t1.id = '1'
UPDATE
Well the problem that I have with the UNION/UNION ALL is this: I don't know what the t1.oldId value is equal to. All I know is the id for t1. I am trying to avoid using 2 queries so is there a way I could do something like this:
SELECT t1.*
FROM table t1
WHERE t1.id = '1'
UNION
SELECT t2.*
FROM table t2
WHERE t2.id = t1.oldId
SAMPLE DATA
messages_users
id message_id user_id box thread_id latest_id
--------------------------------------------------------
8 1 1 1 NULL NULL
9 2 1 2 NULL 16
10 2 65 1 NULL 15
11 3 65 2 2 NULL
12 3 1 1 2 NULL
13 4 1 2 2 NULL
14 4 65 1 2 NULL
15 5 65 2 2 NULL
16 6 1 1 2 NULL
Query:
SELECT mu.id FROM messages_users mu
JOIN messages_users mu2 ON mu2.latest_id IS NOT NULL
WHERE mu.user_id = '1' AND mu2.user_id = '1' AND ((mu.box = '1'
AND mu.thread_id IS NULL AND mu.latest_id IS NULL) OR mu.id = mu2.latest_id)
This query fixes my problem. But it seems the answer to my question is to not use a JOIN but a UNION.
You mean one row for t1 and one row from t2?
You're looking for UNION, not JOIN.
select * from table where id = 1
union
select * from table where oldid = 1
If you are trying to multiply rows in a table, you need UNION ALL (not UNION):
select *
from ((select * from t) union all
(select * from t)
) t
I also sometimes use a cross join to do this:
select *
from t cross join
(select 1 as seqnum union all select 2) vals
The cross join is explicitly multiplying the number of rows, in this case, with a sequencenumber attached.
Well, since it's the same table, you could do:
SELECT t2.*
FROM table t1
JOIN table t2
ON t2.id = t1.oldId
OR t2.id = t1.id
WHERE t1.id = '1'
Related
TABLE:
id second_id status
1 2 1
2 1 0
1 3 1
3 1 1
1 4 1
4 1 1
I try to select only this unique value where the pair have the same status
OUTPUT:
id second_id status
1 3 1
1 4 1
I try with
SELECT table.id, table.second_id, table.status FROM table
WHERE table.id = 1 and table.status = 1
but this return of course bad results ;)
Thx for help :)
One way to do this is to JOIN the table to itself, looking for matching id and second_id values with the same status. We also check that the second table's id value is greater than the first to avoid duplicates:
SELECT t1.*
FROM test t1
JOIN test t2 ON t2.id = t1.second_id
AND t2.second_id = t1.id
AND t2.status = t1.status
AND t2.id > t1.id
Output:
id second_id status
1 3 1
1 4 1
Demo on dbfiddle
One method uses exists:
select t.*
from t
where exists (select 1
from t t2
where t2.second_id = t.id and
t2.id = t.second_id and
t2.status = t.status
);
Or, expressing this using in and tuples is simpler:
select t.*
from t
where (id, second_id, status) in
(select second_id, id, status from t);
Stuck at join, tried left, right, left outer , right outer joins
table 1
selectionID name type
1 abc 1
2 def 1
3 ghi 2
4 dhi 2
5 gki 2
6 ppp 2
Table 2
TID UserID selectionID isOK
1 10 3 0
2 19 3 0
3 10 8 0
6 10 5 1
Desired result is
join of
select from table 1 where type =2
select from table 2 where UserID = 10
selectionID name type TID userID
3 ghi 2 1 10
4 dhi 2 undefined undefined/null
5 gki 2 undefined undefined/null
6 ppp 2 6 10
so basically i want all data from table 1 that fits in where clause and their respective data in table 2 with another where clause
As long as i have done research i need to use inner query of second table...am I going right way?
Try the following query:
SELECT t1.selectionID, t1.name, t1.type, t2.tid, t2.userID
FROM table1 t1 LEFT JOIN table2 t2 ON t1.type = t2.TID AND t2.userID = 10
WHERE t1.type = 2;
Stuck at join, tried left, right, left outer , right outer joins ... well LEFT JOIN is same as LEFT OUTER JOIN. BTW, you are looking for a LEFT JOIN probably like
select t1.selectionID,
t1.name,
t1.type,
t2.TID,
t2.UserId
from table1 t1
left join table2 t2 on t1.selectionID = t2.selectionID
and t2.UserId = 10
where t1.type = 2;
You were probably failing because placing the conditions in the where clause. If a row doesn't join you will have nulls in its columns, so a where condition will discard those rows
select *
from table1 t1
left join
table2 t2
on t1.selectionID = t2.selectionID and
t2.userID = 10
where t1.type = 2
Another way, is to force nulled rows to be accepted, using coalesce
select *
from table1 t1
left join
table2 t2
on t1.selectionID = t2.selectionID and
where t1.type = 2 and
coalesce(t2.userID, 10) = 10
select * from table1 t1
left join table2 t2 ON t1.SelectionID = t2.SelectionID
where t1.type = 2 AND t2.UserID = 10
given the following Table1:
RefID intVal SomeVal
----------------------
1 10 val01
1 20 val02
1 30 val03
1 40 val04
1 50 val05
2 10 val06
2 20 val07
2 30 val08
2 40 val09
2 50 val10
3 12 val11
3 14 val12
4 10 val13
5 100 val14
5 150 val15
5 1000 val16
and Table2 containing some RefIDs and intVals like
RefID intVal
-------------
1 11
1 28
2 9
2 50
2 51
4 11
5 1
5 150
5 151
need an SQL Statement to get the next greater intValue for each RefID and NULL if not found in Table1
following is the expected result
RefID intVal nextGt SomeVal
------------------------------
1 11 20 val01
1 28 30 val03
2 9 10 val06
2 50 50 val10
2 51 NULL NULL
4 11 NULL NULL
5 1 100 val14
5 150 150 val15
5 151 1000 val16
help would be appreciated !
Derived table a retrieves minimal values from table1 given refid and intVal from table2; outer query retrieves someValue only.
select a.refid, a.intVal, a.nextGt, table1.SomeVal
from
(
select table2.refid, table2.intval, min (table1.intVal) nextGt
from table2
left join table1
on table2.refid = table1.refid
and table2.intVal <= table1.intVal
group by table2.refid, table2.intval
) a
-- table1 is joined again to retrieve SomeVal
left join table1
on a.refid = table1.refid
and a.nextGt = table1.intVal
Here is Sql Fiddle with live test.
You can solve this using the ROW_NUMBER() function:
SELECT
RefID,
intVal,
NextGt,
SomeVal,
FROM
(
SELECT
t2.RefID,
t2.intVal,
t1.intVal AS NextGt,
t1.SomeVal,
ROW_NUMBER() OVER (PARTITION BY t2.RefID, t2.intVal ORDER BY t1.intVal) AS rn
FROM
dbo.Table2 AS t2
LEFT JOIN dbo.Table1 AS t1 ON t1.RefID = t2.RefID AND t1.intVal >= t2.intVal
) s
WHERE
rn = 1
;
The derived table matches each Table2 row with all Table1 rows that have the same RefID and an intVal that is greater than or equal to Table2.intVal. Each subset of matches is ranked and the first row is returned by the main query.
The nested query uses an outer join, so that those Table2 rows that have no Table1 matches are still returned (with nulls substituted for the Table1 columns).
Alternatively you can use OUTER APPLY:
SELECT
t2.RefID,
t2.intVal,
t1.intVal AS NextGt,
t1.SomeVal
FROM
dbo.Table2 AS t2
OUTER APPLY
(
SELECT TOP (1)
t1.intVal
FROM
dbo.Table1 AS t1
WHERE
t1.RefID = t2.RefID
AND t1.intVal >= t2.intVal
ORDER BY
t1.intVal ASC
) AS t1
;
This method is arguably more straightforward: for each Table2 row, get all matches from Table1 based on the same set of conditions, sort the matches in the ascending order of Table1.intVal and take the topmost intVal.
This can be done with a join, group by, and a case statement, and a trick:
select t1.refid, t2.intval,
min(case when t1.intval > t2.intval then t1.intval end) as min_greater_than_ref,
substring(min(case when t1.intval > t2.intval
then right('00000000'+cast(t1.intval as varchar(255)), 8)+t1.SomeVal)
end)), 9, 1000)
from table1 t1 left join
table2 t2
on t1.refid = t2.refid
group by t1.refid, t2.intval
SO, the trick is to prepend the integer value to SomeValue, zero-padding the integer value (in this case to 8 characters). You get something like: "00000020val01". The minimum on this column is based on the minimum of the integer. The final step is to extract the value.
For this example, I used SQL Server syntax for the concatenation. In other databases you might use CONCAT() or ||.
I have dozen of tables with following format:
Table 1
[idA] [numA]
NULL 8
1 10
2 15
3 16
Table 2
[idB] [numB]
2 14
3 30
4 32
Table 3
[idC] [numC]
NULL 56
1 24
4 37
5 36
...
Now, I'm not sure how to formulate T-Sql query in order to produce following result:
[id] [numA] [numB] [numC] ...
NULL 8 0 56
1 10 0 24
2 15 14 0
3 16 30 0
4 0 32 37
5 0 0 36
Are there any suggestions on how to solve this?
I offer a solution with the full outer join, because that seems like the natural approach:
SELECT coalesce(a.id, b.id, c.id, . . .) as id,
a.NumA, b.NumB, c.NumC, . . .
FROM TableA a full outer join
TableB b
on a.id = b.id full outer join
TableC c
on coalesce(a.id, b.id) = c.id
However, the query needs to be written carefully, to keep the coalesces in line. The one advantage of this approach is that it should use indexes on the id columns for the query.
please try this
select id, max(numa),max(numb),max(numc) from
(
select id,numa,0 as numb,0 as numc from tb1
union all
select id,0 as numa,numb as numb,0 as numc from tb2
union all
select id,0 as numa,0 as numb,numc as numc from tb3
)X
group by id
order by id
Thanks
Rajath
SELECT Maintable.id,
Table1.numA,
Table2.numB,
Table3.numC
FROM (SELECT ida AS id
FROM Table1
UNION
SELECT idb AS id
FROM Table2
UNION
SELECT idc AS id
FROM Table3) MainTable
LEFT JOIN Table1
ON Maintable.id = Table1.Ida
LEFT JOIN Table2
ON Maintable.id = Table2.idB
LEFT JOIN Table3
ON Maintable.id = Table3.idC
Given following table:
rowId AccountId Organization1 Organization2
-----------------------------------------------
1 1 20 10
2 1 10 20
3 1 40 30
4 2 15 10
5 2 20 15
6 2 10 20
How do I identify the records where Organization2 doesn't exist in Organization1 for a particular account
for instance, in the given data above my results will be a single record which will be AccountId 1 because row3 organization2 value 30 doesn't exist in organization1 for that particular account.
SELECT rowId, AccountId, Organization1, Organization2
FROM yourTable yt
WHERE NOT EXISTS (SELECT 1 FROM yourTable yt2 WHERE yt.AccountId = yt2.AccountId AND yt.Organization1 = yt2.Organization2)
There are two possible interpretations of your question. The first (where the Organization1 and Organization2 columns are not equal) is trivial:
SELECT AccountID FROM Table WHERE Organization1 <> Organization2
But I suspect you're asking the slightly more difficult interpretation (where Organization2 does not appear in ANY Organization1 value for the same account):
SELECT AccountID From Table T1 WHERE Organization2 NOT IN
(SELECT Organization1 FROM Table T2 WHERE T2.AccountID = T1.AccountID)
Here is a how you could do it:
Test data:
CREATE TABLE #T(rowid int, acc int, org1 int, org2 int)
INSERT #T
SELECT 1,1,10,10 UNION
SELECT 2,1,20,20 UNION
SELECT 3,1,40,30 UNION
SELECT 4,2,10,10 UNION
SELECT 5,2,15,15 UNION
SELECT 6,2,20,20
Then perform a self-join to discover missing org2:
SELECT
*
FROM #T T1
LEFT JOIN
#T T2
ON t1.org1 = t2.org2
AND t1.acc = t2.acc
WHERE t2.org1 IS NULL
SELECT
*
FROM
[YorTable]
WHERE
[Organization1] <> [Organization2] -- The '<>' is read "Does Not Equal".
Use left join as Noel Abrahams presented.