Let's assume we have such data set:
Table: DataTable1
ID ExperienceId LanguageId ...
-------------------------------------------
1 1 1
2 1 2
3 1 3
4 2 1
5 2 2
6 2 3
7 3 1
8 3 2
9 3 3
...
Table: DataTable2
ID SomeId OtherId LanguageId ...
-------------------------------------------
1 459 1 1
2 459 1 2
3 459 1 3
4 245 2 1
5 245 2 2
6 245 2 3
7 295 3 1
8 295 3 2
9 295 3 3
...
I want to join those tables and get only SomeId column ignoring the LanguageId column. To make it clearer:
SELECT
t2.SomeId AS RequiredId
-- ...other data mainly from t2
FROM DataTable1 AS t1
LEFT JOIN DataTable2 AS t2
ON t2.OtherId = t1.ExperienceId
AND t2.LanguageId =
(SELECT TOP 1 t1.LanguageId
ORDER BY t1.LanguageId)
This query should return (if it wasn't wrong, clearly) rows:
SomeId ...
----------------
459 ...
245 ...
295 ...
...
Now it returns three times of identical data (with only LanguageId different).
I would try to filter it with WHERE t1.LanguageId = 1 if I was sure it always exists, but I'm not sure. Rows can be with LanguageId from 1 to 3, also they can be only with ID 2, etc. Rows surely will have at least one LanguageId.
Now my question is: how can I join tables with unique values with one column completely ignored?
Wrapping it in another query does the trick?
SELECT RequiredId, <all_the_other_fields> from (
SELECT t2.SomeId AS RequiredId
-- ...other data mainly from t2
FROM DataTable1 AS t1
LEFT JOIN DataTable2 AS t2
ON t2.OtherId = t1.ExperienceId
AND t2.LanguageId =
(SELECT TOP 1 t1.LanguageId
ORDER BY t1.LanguageId)
) group by RequiredId, <all_the_other_fields>
or even not extracting the column in the first place?
SELECT distinct t2.SomeId AS RequiredId
-- ...other data mainly from t2 BUT not the Language id
FROM DataTable1 AS t1
LEFT JOIN DataTable2 AS t2
ON t2.OtherId = t1.ExperienceId
AND t2.LanguageId =
(SELECT TOP 1 t1.LanguageId
ORDER BY t1.LanguageId)
Try this:
;with cte as
(select *, row_number() over (partition by someid order by languageid) rn
from datatable2)
select *
from datatable1 dt
left join cte c on dt.experienceid = c.otherid and c.rn = 1
For such things when you need to select top in the subquery CROSS APPLY OR 'OUTER APPLY' is very handy
t2.SomeId AS RequiredId
-- ...other data mainly from t2
FROM DataTable1 AS t1
OUTER APPLY ( SELECT TOP 1 t1.LanguageId
FROM DataTable2
WHERE DataTable2 .OtherId = t1.ExperienceId
AND t2.LanguageId = t1.LanguageId
ORDER BY t1.LanguageId
) AS t2
Try this:
SELECT DISTINCT t2.SomeId AS RequiredId
-- ...other data mainly from t2
FROM DataTable1 AS t1
LEFT JOIN DataTable2 AS t2
ON t2.OtherId = t1.ExperienceId
WHERE t2.LanguageId = t1.LanguageId
Are you looking for this (Fiddle: http://sqlfiddle.com/#!3/811b8/12)?:
SELECT dt2.*
FROM DataTable1 dt1 INNER JOIN DataTable2 dt2
ON dt1.ExperienceID = dt2.OtherID AND
dt1.LanguageID = dt2.LanguageID
WHERE dt2.LanguageID = (SELECT MIN(LanguageID) FROM DataTable1);
produces:
ID SOMEID OTHERID LANGUAGEID
1 459 1 1
4 245 2 1
7 295 3 1
Related
Let say I am working under SAS EG and I have 2 tables:
Table1:
Id Item
1 A
1 B
1 C
2 B
2 D
3 C
3 E
3 F
Table2:
Id Item Amount
1 A 99
2 C 100
1 B 100
2 A 90
1 A 93
3 B 92
1 E 93
2 B 99
1 A 93
Now I would like to take the sum conditional for my table1 from table2 (when the ID and the Item match).
Id Item Want
1 A 285
1 B 100
1 C 0
2 B 99
2 D 0
3 C 0
3 E 0
3 F 0
So what am I supposed to do in SQL?
Thanks in advance.
Use a correlated subquery to SUM:
select t1.Id, t1.Item,
(select sum(t2.amount) from table2 t2 where t2.id = t1.id and t2.item = t1.item)
from table1 t1
This looks like aggregation to me, with a left join:
select t1.id, t1.item,
coalesce(sum(t2.amount), 0) as want
from table1 t1 left join
table2 t2
on t1.id = t2.id and t2.item = t2.item
group by t1.id, t1.item;
Table1 CompanyID Location #-of-employees
5234 NY 10
5268 DC 2
5879 NY 8
6897 KS 100
8789 CA 1
9992 OH 201
9877 TX 15
Table2 CompanyID #-of-Shareholders
5234 5
5879 2
6897 4
8789 2
I have two table with the column CompanyID. In table2 you can find companies that have shareholders and in table1 you can find all the companies. So in table 1 I want to add a dummy variable that assign a 1 if the companyID is in table2(which means the company has shareholders) and a 0 if not.
Expected output:
Table1 CompanyID Location #-of-employees Dummy
5234 NY 10 1
5268 DC 2 0
5879 NY 8 1
6897 KS 100 1
8789 CA 1 1
9992 OH 201 0
9877 TX 15 0
I tried using this query but it doesn't give me the output I expect.
SELECT CASE WHEN companyID IN table2 THEN 1
ELSE 0
END AS dummy
FROM table1
You have to use the Subquery for this. the below code working fine.
SELECT CASE WHEN companyID in(select CompanyId from table2) THEN 1
ELSE 0
END AS dummy
FROM table1
You can use EXISTS
SELECT CASE
WHEN EXISTS(SELECT 1 FROM Table2 AS T2 WHERE T1.CompanyID = T2.CompanyID) THEN 1
ELSE 0
END AS Dummy
FROM Table1 AS T1;
If your DB's version is 2012+ then, use with left join as :
select t1.*, iif(#_of_Shareholders is null, 0, 1) as dummy
from table1 t1
left join table2 t2
on ( t1.CompanyID = t2.CompanyID );
else
select t1.*,
( case when #_of_Shareholders is null then 0 else 1 end )
as dummy
from table1 t1
left join table2 t2
on ( t1.CompanyID = t2.CompanyID );
or
select t1.*,
sign(coalesce(#_of_Shareholders,0))
as dummy
from table1 t1
left join table2 t2
on ( t1.CompanyID = t2.CompanyID );
Rextester Demo
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'
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 ||.
Consider tables
Table1
id, name
1 xyz
2 abc
3 pqr
Table2
id title
1 Mg1
2 Mg2
3 SG1
Table3
Tb1_id tb2_id count
1 1 3
1 2 3
1 3 4
2 2 1
3 2 2
3 3 2
I want to do query to give result like
id title
1 MG1
2 MG2
3 Two or More Title
MG1 has higher preference if MG1 and count >= 1 then it is given as MG1 title , for others corresponding title is used and for count > 1 as two or more
I think this is what you are going for:
select t3.Tb1_id as id,
case
when mg1cnt.count >= 1 then 'MG1'
when cnt.count = 1 then upper(t2.title)
else 'Two or More Titles'
end as title
from (
select Tb1_id, count(*) as count
from Table3
group by Tb1_id
) cnt
inner join (
select Tb1_id, isnull(SUM(case when t2.title='mg1' then 1 end), 0) as count
from Table3 t3
inner join Table2 t2 on t3.tb2_id = t2.id
group by Tb1_id
) as mg1cnt on cnt.Tb1_id = mg1cnt.Tb1_id
inner join Table3 t3 on cnt.Tb1_id = t3.Tb1_id
inner join Table2 t2 on t3.tb2_id = t2.id
group by t3.Tb1_id,
case
when mg1cnt.count >= 1 then 'MG1'
when cnt.count = 1 then upper(t2.title)
else 'Two or More Titles'
end