I would like to embed a SELECT inside a COUNT, but I can't find any examples.
#pseudosql
SELECT a AS current_a, COUNT(*) AS b,
COUNT( SELECT FROM t WHERE a = current_a AND c = 'const' ) as d,
from t group by a order by b desc
You don't really need a sub-select:
SELECT a, COUNT(*) AS b,
SUM( CASE WHEN c = 'const' THEN 1 ELSE 0 END ) as d,
from t group by a order by b desc
You can move the count() inside your sub-select:
SELECT a AS current_a, COUNT(*) AS b,
( SELECT COUNT(*) FROM t WHERE a = current_a AND c = 'const' ) as d,
from t group by a order by b desc
Use SELECT COUNT(*) FROM t WHERE a = current_a AND c = 'const' ) as d.
SELECT a AS current_a, COUNT(*) AS b,
(SELECT COUNT(*) FROM t WHERE a = current_a AND c = 'const' ) as d
from t group by a order by b desc
Related
SELECT a, b
FROM "table1".table1 table1
ORDER BY a DESC
UNION ALL
SELECT a, b
FROM "table1".table1 table1
ORDER BY a ASC
This query does not work. Individually, union all works and order by works, but does not work when together. Can someone please help?
Answered this question on GridGain forum
This should work:
SELECT a, b, b, NULL FROM "table1".table1 table1
UNION ALL
SELECT a, b, NULL, b FROM "table1".table1 table1
ORDER BY 3 DESC, 4 ASC
You can sort in an outer query:
select a, b
from (
select a, b, 0 x from table1
union all select a, b, 1 from table1
) t
order by
x,
case when x = 0 then a end desc,
case when x = 1 then a end
Individual query won't support order by if we are using UNION.
Try to remove order by in separate query and after union they to perform order by then it will work.
I'm trying to select the last MAX(DateTime) status from the table "Zee" but if the DateTime is the same it returns two lines, and I would like to get only the last one (maybe last inserted?).
here is the query:
SELECT Z."ID" AS ID,Z."A" AS A,Z."B" AS B,Z."C" AS C,Z."D" AS D
FROM ZEE Z
INNER JOIN
(SELECT ID, A, B, MAX(C) AS C
FROM ZEE
GROUP BY A, B) groupedtt
ON Z.A = groupedtt.A
AND Z.B = groupedtt.B
AND Z.C = groupedtt.C
WHERE (
Z.B = 103
OR Z.B = 104
);
and the result:
Thanks,
Regards.
I usually use rank() for such things:
select Z."ID" AS ID,Z."A" AS A,Z."B" AS B,Z."C" AS C,Z."D" AS D
from (select Z.*, rank()over(partition by A,B order by C desc, rownum) r from ZEE Z
)Z where Z.r=1
Use the ROW_NUMBER() analytic function (you will also eliminate the self-join):
SELECT ID, A, B, C, D
FROM (
SELECT ID,
A,
B,
C,
D,
ROW_NUMBER() OVER ( PARTITION BY A, B ORDER BY C DESC ) As rn
FROM ZEE
)
WHERE rn = 1;
create table #middle
(
A INT,
B INT,
C INT
)
INSERT INTO #middle (A,B,C) VALUES (7,6,2),(1,0,8),(9,12,16),(7, 16, 2),(1,12,8), (9,12,16),(9,12,16),(7, 16, 2),(1,12,8), (9,12,16)
;WITH MIDS
AS (SELECT *,
Row_number()
OVER (
ORDER BY a, b, c DESC )AS rn
FROM #middle)
SELECT *
FROM MIDS
WHERE rn <= (SELECT CASE ( Count(*)%2 )
WHEN 0 THEN ( Count(*) / 2 ) + 1
ELSE ( Count(*) / 2 )
END
FROM MIDS) except (SELECT *
FROM MIDS
WHERE rn < (SELECT ( Count(*) / 2 )
FROM MIDS))
The query i have tried works >4 records but not for '3'.Now my question is how should i modify my query so that for 3 records i should get the 2nd record which is the middle most record among them,try to insert only 3 records from above records and help. Thanks in advance.
You can use OFFSET and FETCH
select *
from #middle
order by a, b, c desc
offset (select count(*) / 2 - (case when count(*) % 2 = 0 then 1 else 0 end) from #middle) rows
fetch next (select 2 - (count(*) % 2) from #middle) rows only
There are many ways to get the median in SQL. Here is a simple way:
select h.*
from (select h.*, row_number() over (order by a, b, c desc) as seqnum,
count(*) over () as cnt
from #highest h
) h
where 2 * rn in (cnt, cnt - 1, cnt + 1);
For an even number of records, you will get two rows. You need to decide what you actually want in this case.
How about this:
**EDITED
;WITH MIDS
AS (SELECT *,
Row_number()
OVER (
ORDER BY a, b, c DESC )AS rn
FROM #middle),
Cnt
AS
(SELECT COUNT(*) c, COUNT(*)%2 as rem, COUNT(*)/2 as mid FROM Mids)
SELECT *
FROM MIDS
CROSS APPLY cnt
where (rn >= cnt.mid and rn <= cnt.mid + 1 AND cnt.rem = 0) OR
(cnt.rem <> 0 AND rn = cnt.mid+1)
I have a table that has millions of records.
So I might have these columns
a, b, c, d
I need to select all the distinct records based on columns a and b.
But I need to select columns a, b, c and d not just a and b.
Can I do this?
edit
Data might be
1,1,frog,green
1,1,frog,brown
2,1,cat,black
2,4,dog,white
so i need;
1,1,frog,green
2,1,cat,black
2,4,dog,white
SQL Server supports Common Table Expression and Window Function. The query below uses ROW_NUMBER() which ranks the record according to group. It sorts by c ASC, d ASC (just play with it).
WITH records
AS
(
SELECT a, b, c, d,
ROW_NUMBER() OVER(PARTITION BY a, b ORDER BY c, d) rn
FROM TableName
)
SELECT a, b, c, d
FROM records
WHERE rn = 1
SQLFiddle Demo
TSQL Ranking Functions
partition by is your man
SELECT a, b, c, d FROM (
SELECT a, b, c, d, ROW_NUMBER() OVER (PARTITION BY a, b ORDER BY a, b) rn
FROM table
) sq
where rn = 1
Please try:
select *
From(
select
row_number() over (partition by a, b order by a, b) RNum,
*
from
YourTable
)x
where RNum=1
Sample
select * From(
select row_number() over (partition by a, b order by a, b) RNum, *
from(
select 1 a, 1 b, 'frog' c, 'green' d union all
select 1 a, 1 b, 'frog' c, 'brown' d union all
select 2 a, 1 b, 'cat' c, 'black' d union all
select 2 a, 4 b, 'dog' c, 'white' d)x
)y
where RNum=1
I have a query like:
SELECT
R.*
FROM
(SELECT A, B,
(SELECT smth from another table) as C,
ROW_NUMBER() OVER (ORDER BY C DESC) AS RowNumber
FROM SomeTable) R
WHERE
RowNumber BETWEEN 10 AND 20
This gives me an error on ORDER BY C DESC.
I understand why this error is caused, so I've thought of adding another SELECT with ORDER BY and only than selecting rows from 10 to 20. But I don't think it's good to have 3 nested SELECT commands.
How else is it possible to select these rows?
A column cannot refer to an alias on same level, you have to table-derive it first, or use CTE.
SELECT
R.* , ROW_NUMBER() OVER (ORDER BY C DESC) AS RowNumber
FROM
(SELECT A, B, (SELECT smth from another table) as C
FROM SomeTable) R
-- WHERE
-- but you still cannot do this
-- RowNumber BETWEEN 10 AND 20
Need to do this:
select S.*
from
(
SELECT
R.* , ROW_NUMBER() OVER (ORDER BY C DESC) AS RowNumber
FROM
(SELECT A, B,
(SELECT smth from another table) as C
FROM SomeTable) R
) as s
where s.RowNumber between 10 and 20
To avoid deep nesting and to make it at least look pleasant, use CTE:
with R as
(
SELECT A, B, (SELECT smth from another table) as C
FROM SomeTable
)
,S AS
(
SELECT R.*, ROW_NUMBER() OVER (ORDER BY C DESC) AS RowNumber
FROM R
)
SELECT S.*
FROM S
WHERE S.RowNumber BETWEEN 1 AND 20
You cannot use aliased columns in the same SELECT, but you can wrap it into another select to make it work:
SELECT R.*
FROM (SELECT ABC.A, ABC.B, ABC.C, ROW_NUMBER() OVER (ORDER BY C DESC) AS RowNumber
FROM (SELECT A, B, (SELECT smth from another table) as C FROM SomeTable) ABC
) R
WHERE R.RowNumber BETWEEN 10 AND 20