I have two queries that give me back a single entry. How can I select both of these as on table?
query1: Select max([column3]) from [table1] => 42
query2: Select Top 1 [column1] from [table1] => 'test'
I want a resultset like this
result1
result2
42
'test'
But how to do it correctly? Can I maybe select from nowhere somehow?
You could use ROW_NUMBER, twice:
WITH cte AS (
SELECT *, ROW_NUMBER() OVER (ORDER BY column3 DESC) rn1,
ROW_NUMBER() OVER (ORDER BY some_col) rn2
FROM table1
)
SELECT MAX(CASE WHEN rn1 = 1 THEN column3 END) AS result1,
MAX(CASE WHEN rn2 = 1 THEN column1 END) AS result2
FROM cte;
Note that I assume there exists a column some_col which you intend to use for choosing the column1 value.
Related
I'm trying to do a query on Postgres but it's not working. I'd like to create an insert query with 2 select:
Example :
INSERT INTO table1 (id_1, id_2)
SELECT id from table_2 where code='01',
SELECT id from table_2 where code='02';
I don't find the good syntax for this.
I believe below query will works for your use case
INSERT INTO stats(totalProduct, totalCustomer, totalOrder)
VALUES(
(SELECT COUNT(*) FROM products),
(SELECT COUNT(*) FROM customers),
(SELECT COUNT(*) FROM orders)
);
you can changes query accordingly
You can add one more SELECT to achieve this
INSERT INTO table_1 (id_1, id_2)
SELECT
(SELECT id FROM table_2 WHERE code = '01') AS Id_1,
(SELECT id FROM table_2 WHERE code = '02') AS Id_2;
Or you may try with CASE expression:
INSERT INTO table1 (id_1, id_2)
SELECT MAX(CASE WHEN code = '01' THEN id ELSE 0 END) AS Id_1,
MAX(CASE WHEN code = '02' THEN id ELSE 0 END) AS Id_2
FROM table_2
Please refer to the working fiddle on db<>fiddle
I have a very similar problem to the question asked here: Merge duplicate temporal records in database
The difference here is, that I need the end date to be an actual date instead of NULL.
So given the following data:
EmployeeId StartDate EndDate Column1 Column2
1000 2009/05/01 2010/04/30 X Y
1000 2010/05/01 2011/04/30 X Y
1000 2011/05/01 2012/04/30 X X
1000 2012/05/01 2013/04/30 X Y
1000 2013/05/01 2014/04/30 X X
1000 2014/05/01 2014/06/01 X X
The desired result is:
EmployeeId StartDate EndDate Column1 Column2
1000 2009/05/01 2011/04/30 X Y
1000 2011/05/01 2012/04/30 X X
1000 2012/05/01 2013/04/30 X Y
1000 2013/05/01 2014/06/01 X X
The proposed solution in the linked thread is this:
with t1 as --tag first row with 1 in a continuous time series
(
select t1.*, case when t1.column1=t2.column1 and t1.column2=t2.column2
then 0 else 1 end as tag
from test_table t1
left join test_table t2
on t1.EmployeeId= t2.EmployeeId and dateadd(day,-1,t1.StartDate)= t2.EndDate
)
select t1.EmployeeId, t1.StartDate,
case when min(T2.StartDate) is null then null
else dateadd(day,-1,min(T2.StartDate)) end as EndDate,
t1.Column1, t1.Column2
from (select t1.* from t1 where tag=1 ) as t1 -- to get StartDate
left join (select t1.* from t1 where tag=1 ) as t2 -- to get a new EndDate
on t1.EmployeeId= t2.EmployeeId and t1.StartDate < t2.StartDate
group by t1.EmployeeId, t1.StartDate, t1.Column1, t1.Column2;
However, this does not seem to work when you need the end date instead of just NULL.
Could someone help me with this issue?
How about this?
create table test_table (EmployeeId int, StartDate date, EndDate date, Column1 char(1), Column2 char(1))
;
insert into test_table values
(1000 , '2009-05-01','2010-04-30','X','Y')
,(1000 , '2010-05-01','2011-04-30','X','Y')
,(1000 , '2011-05-01','2012-04-30','X','X')
,(1000 , '2012-05-01','2013-04-30','X','Y')
,(1000 , '2013-05-01','2014-04-30','X','X')
,(1000 , '2014-05-01','2014-06-01','X','X')
;
SELECT EmployeeId, StartDate, EndDate, Column1, Column2 FROM
(
SELECT EmployeeId, StartDate
, MAX(EndDate) OVER(PARTITION BY EmployeeId, RN) AS EndDate
, Column1
, Column2
, DIFF
FROM
(
SELECT t.*
, SUM(DIFF) OVER(PARTITION BY EmployeeId ORDER BY StartDate ) AS RN
FROM
(
SELECT t.*
, CASE WHEN
Column1 = LAG(Column1,1) OVER(PARTITION BY EmployeeId ORDER BY StartDate)
AND Column2 = LAG(Column2,1) OVER(PARTITION BY EmployeeId ORDER BY StartDate)
THEN 0 ELSE 1 END AS DIFF
FROM
test_table t
) t
)
)
WHERE DIFF = 1
;
This is another solution (taken from How do I group on continuous ranges). It is simpler to code and also caters for NULL values (i.e. treats NULL = NULL unlike the simple LAG() comparison). However it might not be quite as efficient on large volumes of data due to the GROUP BY
SELECT EmployeeId
, MIN(StartDate) AS StartDate
, MAX(EndDate) AS EndDate
, Column1
, Column2
FROM
(
SELECT t.*
, ROW_NUMBER() OVER(PARTITION BY EmployeeId, Column1, Column2 ORDER BY StartDate ) AS GRN
, ROW_NUMBER() OVER(PARTITION BY EmployeeId ORDER BY StartDate ) AS RN
FROM
test_table t
) t
GROUP BY
EmployeeId
, Column1
, Column2
, RN - GRN
I need to write a T-SQL group by query for a table with multiple dates and seq columns:
DROP TABLE #temp
CREATE TABLE #temp(
id char(1),
dt DateTime,
seq int)
Insert into #temp values('A','2015-03-31 10:00:00',1)
Insert into #temp values('A','2015-08-31 10:00:00',2)
Insert into #temp values('A','2015-03-31 10:00:00',5)
Insert into #temp values('B','2015-09-01 10:00:00',1)
Insert into #temp values('B','2015-09-01 10:00:00',2)
I want the results to contains only the items A,B with their latest date and the corresponding seq number, like:
id MaxDate CorrespondentSeq
A 2015-08-31 10:00:00.000 2
B 2015-09-01 10:00:00.000 2
I am trying with (the obviously wrong!):
select id, max(dt) as MaxDate, max(seq) as CorrespondentSeq
from #temp
group by id
which returns:
id MaxDate CorrespondentSeq
A 2015-08-31 10:00:00.000 5 <-- 5 is wrong
B 2015-09-01 10:00:00.000 2
How can I achieve that?
EDIT
The dt datetime column has duplicated values (exactly same date!)
I am using SQL Server 2005
You can use a ranking subselect to get only the highest ranked entries for an id:
select id, dt, seq
from (
select id, dt, seq, rank() over (partition by id order by dt desc, seq desc) as r
from #temp
) ranked
where r=1;
SELECT ID, DT, SEQ
FROM (
SELECT ID, DT, SEQ, Row_Number()
OVER (PARTITION BY id ORDER BY dt DESC, seq DESC) AS row_number
FROM temp
) cte
WHERE row_number = 1;
Demo : http://www.sqlfiddle.com/#!3/3e3d5/5
With trial and errors maybe I have found a solution, but I'm not completely sure this is correct:
select A.id, B.dt, max(B.seq)
from (select id, max(dt) as maxDt
from #temp
group by id) as A
inner join #temp as B on A.id = B.id AND A.maxDt = B.dt
group by A.id, B.dt
Select id, dt, seq
From #temp t
where dt = (Select Max(dt) from #temp
Where id = t.Id)
If there are duplicate rows, then you also need to specify what the query processor should use to determine which of the duplicates to return. Say you want the lowest value of seq,
Then you could write:
Select id, dt, seq
From #temp t
where dt = (Select Max(dt) from #temp
Where id = t.Id)
and seq = (Select Min(Seq) from #temp
where id = t.Id
and dt = t.dt)
I made two queries that I thought should have the same result:
SELECT COUNT(*) FROM (
SELECT DISTINCT ON (id1) id1, value
FROM (
SELECT table1.id1, table2.value
FROM table1
JOIN table2 ON table1.id1=table2.id
WHERE table2.value = '1')
AS result1 ORDER BY id1)
AS result2;
SELECT COUNT(*) FROM (
SELECT DISTINCT ON (id1) id1, value
FROM (
SELECT table1.id1, table2.value
FROM table1
JOIN table2 ON table1.id1=table2.id
)
AS result1 ORDER BY id1)
AS result2
WHERE value = '1';
The only difference being that one had the WHERE clause inside SELECT DISTINCT ON, and the other outside that, but inside SELECT COUNT. But the results were not the same. I don't understand why the position of the WHERE clause should make a difference in this case. Can anyone explain? Or is there a better way to phrase this question?
here's a good way to look at this:
SELECT DISTINCT ON (id) id, value
FROM (select 1 as id, 1 as value
union
select 1 as id, 2 as value) a;
SELECT DISTINCT ON (id) id, value
FROM (select 1 as id, 1 as value
union
select 1 as id, 2 as value) a
WHERE value = 2;
The problem has to do with the unique conditions and what is visible where. It is behavior by design.
I have to make query on WITH query, something like
; WITH #table1
(
SELECT id, x from ... WHERE....
UNION ALL
SELECT id, x from ... WHERE...
)
WITH #table2
(
SELECT DISTINCT tbl_x.*,ROW_NUMBER() OVER (order by id) as RowNumber
WHERE id in ( SELECT id from #table1)
)
SELECT * FROM #table2 WHERE RowNumber > ... and ...
So I have to use WITH on WITH and then SELECT on second WITH, How I can do that?
You can define multiple CTEs after the WITH keyword by separating each CTE with a comma.
WITH T1 AS
(
SELECT id, x from ... WHERE....
UNION ALL
SELECT id, x from ... WHERE...
)
, T2 AS
(
SELECT DISTINCT tbl_x.*, ROW_NUMBER() OVER (order by id) as RowNumber
WHERE id in ( SELECT id from T1 )
)
SELECT * FROM T2 WHERE RowNumber > ... and ...
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