How do I a select against a table A for example which contains these records.
|Column1|Column2|
| A |F |
| A | G |
| B |G |
| B |H |
| C |H |
| D |H |
| E |I |
My expected result is:
|Column1 |Column2|
| A | F |
| B | G |
| C | H |
| E | I |
All columns should have a unique value in them.
What query statement can I use for this?
Thanks
Please try:
select
MIN(Column1) Column1,
Column2
from(
select
Column1,
MIN(Column2) Column2
from YourTable
group by Column1
)x group by Column2
order by 1
SQL Fiddle Demo
It didn't work for this scenario.
create table YourTable (Column1 varchar2(10),
Column2 varchar2(10));
insert into YourTable values ('B','F');
insert into YourTable values ('B','G');
insert into YourTable values ('B','H');
insert into YourTable values ('C','F');
insert into YourTable values ('C','G');
insert into YourTable values ('C','H');
insert into YourTable values ('D','F');
insert into YourTable values ('D','G');
insert into YourTable values ('D','H');
My expectation is
B F
C G
D H
but I only got
B F
Thanks a lot!
SELECT a.val, b.val FROM
(
SELECT val, rownum as rno
FROM
(
SELECT distinct column1 as val
FROM YourTable
)) a,
(
SELECT val, rownum as rno
FROM
(
SELECT distinct column2 as val
FROM YourTable
)) b
WHERE a.rno = b.rno
ORDER BY 1
/
VAL VAL_1
-----------
B F
C G
D H
OR
select column1 as val from YourTable
UNION
select column2 from YourTable
VAL
-----
B
C
D
F
G
H
Related
I have following sql query
SELECT m.School, c.avgscore
FROM postswithratings c
join ZEntrycriteria on c.fk_postID= m.schoolcode
Which provide following result
School| avgscore
xyz | 5
xyz | 5
xyz | 5
abc | 3
abc | 3
kkk | 1
My question is how to remove those duplicates and get only following.
School| avgscore
xyz | 5
abc | 3
kkk | 1
I tried with
SELECT m.School, c.avgscore
FROM postswithratings c
join ZEntrycriteria on c.fk_postID= m.schoolcode
group by m.School
But it gives me following error
"Column 'postswithratings.avgscore' is invalid in the select list
because it is not contained in either an aggregate function or the
GROUP BY clause."
No need to make things complicated. Just go with:
SELECT m.School, c.avgscore
FROM postswithratings c
join ZEntrycriteria on c.fk_postID= m.schoolcode
group by m.School, c.avgscore
or
SELECT DISTINCT m.School, c.avgscore
FROM postswithratings c
join ZEntrycriteria on c.fk_postID= m.schoolcode
You have to only add distinct keyword like this :-
SELECT DISTINCT m.School, c.avgscore
FROM postswithratings c
join ZEntrycriteria on c.fk_postID= m.schoolcode
CREATE TABLE #Table2
([School] varchar(3), [avgscore] int)
INSERT INTO #Table2
([School], [avgscore])
VALUES
('xyz', 5),
('xyz', 5),
('xyz', 5),
('abc', 3),
('abc', 3),
('kkk', 1)
;
SELECT SCHOOL,AVGSCORE FROM (SELECT *,ROW_NUMBER() OVER( PARTITION BY [AVGSCORE] ORDER BY (SELECT NULL)) AS RN FROM #TABLE2)A
WHERE RN=1
ORDER BY AVGSCORE
-------
;WITH CTE AS
(SELECT *,ROW_NUMBER() OVER( PARTITION BY [AVGSCORE] ORDER BY (SELECT NULL)) AS RN FROM #TABLE2)
SELECT SCHOOL,AVGSCORE FROM CTE WHERE RN=1
output
SCHOOL AVGSCORE
kkk 1
abc 3
xyz 5
Using the DISTINCT keyword will make sql use sets instead of multisets. So values only appear once
This will delete the Duplicate rows (Only Duplicate)
Schema:
CREATE TABLE #TAB (School varchar(5) , avgscore int)
INSERT INTO #TAB
SELECT 'xyz', 5
UNION ALL
SELECT 'xyz', 5
UNION ALL
SELECT 'xyz', 5
UNION ALL
SELECT 'abc', 3
UNION ALL
SELECT 'abc', 3
UNION ALL
SELECT 'kkk', 1
Now use CTE as your Tempprary View and delete the data.
;WITH CTE AS(
SELECT ROW_NUMBER() OVER (PARTITION BY School,avgscore ORDER BY (SELECT 1)) DUP_C,
School, avgscore FROM #TAB
)
DELETE FROM CTE WHERE DUP_C>1
Now do check #TAB, the data will be
+--------+----------+
| School | avgscore |
+--------+----------+
| xyz | 5 |
| abc | 3 |
| kkk | 1 |
+--------+----------+
you only use group by if you're using aggregated function, eg. max. sum, avg
in that case,
SELECT Distinct(m.School), c.avgscore
FROM postswithratings c
join ZEntrycriteria on c.fk_postID= m.schoolcode
I have a two tables that are setup like the following examples
tablea
ID | Name
1 | val1
1 | val2
1 | val3
2 | other1
3 | other
tableb
ID | Amount
1 | $100
2 | $50
My desired output would be to left join tableb to tablea but only join tableb once on each value. ID is the only relationship
tablea.ID | tablea.Name | tableb.id | tableb.amount
1 | val1 | 1 | $100
1 | val2
1 | val3
2 | other1 | 2 | $50
3 | other
Microsoft SQL
You can do the following:
select ROW_NUMBER() OVER(ORDER BY RowID ASC) as RowNum, ID , Name
from tablea
which gives you :
RowNum | RowID | Name
1 | 1 | val1
2 |1 | val2
3 |1 | val3
4 |2 | other1
5 |3 | other
You then get the minimum row number for each RowID:
Select RowId, min(RowNum)
From (
select ROW_NUMBER() OVER(ORDER BY RowID ASC) as RowNum, ID , Name
from tablea )
Group By RowId
Once you have this you can then join tableb onto tablea only where the RowId is the minimum
WITH cteTableA As (
select ROW_NUMBER() OVER(ORDER BY RowID ASC) as RowNum, ID , Name
from tablea ),
cteTableAMin As (
Select RowId, min(RowNum) as RowNumMin
From cteTableA
Group By RowId
)
Select a.RowID, a.Name, b.Amount
From cteTableA a
Left join cteTableAMin amin on a.RowNum = amin.RowNumMin
and a.ID = amin.RowId
Left join tableb b on amin.ID = b.ID
This can be tidied up... but helps to show whats going on.
Then you MUST specify which row in tableA you wish to join to. If there are more than one row in the other table, How can the query processor know which one you want ?
If you want the one with the lowest value of name, then you might do this:
Select * from tableB b
join tableA a
on a.id = b.Id
and a.name =
(Select min(name) from tableA
where id = b.id)
but even that won't work if there multiple rows with the same values for both id AND name. What you might really need is a Primary Key on tableA.
Use:
select
a.id,
a.name,
b.amount
from
(select
id,
name,
row_number() over (partition by id order by name) as rn
from tablea) a
left join (
select
id,
amount,
row_number() over (partition by id order by amount) as rn
from tableb) b
on a.id = b.id
and a.rn = b.rn
order by a.id, a.name
In a table there are two columns:
-----------
| A | B |
-----------
| 1 | 5 |
| 2 | 1 |
| 3 | 2 |
| 4 | 1 |
-----------
Want a table where if A=B then
-------------------
|Match | notMatch|
-------------------
| 1 | 5 |
| 2 | 3 |
| Null | 4 |
-------------------
How can i do this?
I tried something which shows the Matched part
select distinct C.A as A from Table c inner join Table d on c.A=d.B
Try this:
;WITH TempTable(A, B) AS(
SELECT 1, 5 UNION ALL
SELECT 2, 1 UNION ALL
SELECT 3, 2 UNION ALL
SELECT 4, 1
)
,CTE(Val) AS(
SELECT A FROM TempTable UNION ALL
SELECT B FROM TempTable
)
,Match AS(
SELECT
Rn = ROW_NUMBER() OVER(ORDER BY Val),
Val
FROM CTE c
GROUP BY Val
HAVING COUNT(Val) > 1
)
,NotMatch AS(
SELECT
Rn = ROW_NUMBER() OVER(ORDER BY Val),
Val
FROM CTE c
GROUP BY Val
HAVING COUNT(Val) = 1
)
SELECT
Match = m.Val,
NotMatch= n.Val
FROM Match m
FULL JOIN NotMatch n
ON n.Rn = m.Rn
Try with EXCEPT, MINUS and INTERSECT Statements.
like this:
SELECT A FROM TABLE1 INTERSECT SELECT B FROM TABLE1;
You might want this:
SELECT DISTINCT
C.A as A
FROM
Table c
LEFT OUTER JOIN
Table d
ON
c.A=d.B
WHERE
d.ID IS NULL
Please Note that I use d.ID as an example because I don't see your schema. An alternate is to explicitly state all d.columns IS NULL in WHERE clause.
Your requirement is kind of - let's call it - interesting. Here is a way to solve it using pivot. Personally I would have chosen a different table structure and another way to select data:
Test data:
DECLARE #t table(A TINYINT, B TINYINT)
INSERT #t values
(1,5),(2,1),
(3,2),(4,1)
Query:
;WITH B AS
(
( SELECT A FROM #t
EXCEPT
SELECT B FROM #t)
UNION ALL
( SELECT B FROM #t
EXCEPT
SELECT A FROM #t)
), A AS
(
SELECT A val
FROM #t
INTERSECT
SELECT B
FROM #t
), combine as
(
SELECT val, 'A' col, row_number() over (order by (select 1)) rn FROM A
UNION ALL
SELECT A, 'B' col, row_number() over (order by (select 1)) rn
FROM B
)
SELECT [A], [B]
FROM combine
PIVOT (MAX(val) FOR [col] IN ([A], [B])) AS pvt
Result:
A B
1 3
2 4
NULL 5
Suppose I have two tables A and B
Table A
name | age
----------------
jack | 13
hanna | 28
Table B
id
-----
1
2
I want to insert in another table C the following
Table C
id | name | age
--------------------
1 | jack | 13
2 | hanna | 28
I'm doing this
INSERT INTO C (id, name, age)
SELECT b.id, a.name, a.age
FROM A a, B b
Intead of getting what I want, I get this :
id | name | age
--------------------
1 | jack | 13
1 | hanna | 28
2 | jack | 13
2 | hanna | 28
How could you resolve this ?
declare #a table (name varchar(50),age int)
Declare #b table (id int)
insert into #a
select 'jack',13
union select 'hanna',28
insert into #b
select 1
union select 2
Select id,name,age from
(
Select a.* ,ROW_Number() over (order by name) as rn
from #a a
)x
JOIN
(
Select b.* ,ROW_Number() over (order by ID) as rn
from #b b
)y
ON x.rn=y.rn
order by ID
You can write this query to get the insert desired rows in table c
insert into #c
select id, name, age from (
( select ROW_NUMBER() over (order by name) as Aid, name, age from #A ) ATest
inner join (select ROW_NUMBER() over (order by id) as Bid, id from #B) Btest on Aid = Bid
)
Say I have the following table:
MyTable
---------
| 1 | A |
| 2 | A |
| 3 | A |
| 4 | B |
| 5 | B |
| 6 | B |
| 7 | A |
| 8 | A |
---------
I need the sql query to output the following:
---------
| 3 | A |
| 3 | B |
| 2 | A |
---------
Basically I'm doing a group by but only for rows which are together in the sequence. Any ideas?
Note that the database is on sql server 2008. There is a post on this topic however it uses oracle's lag() function.
This is known as the "islands" problem. Using Itzik Ben Gan's approach:
;WITH YourTable AS
(
SELECT 1 AS N, 'A' AS C UNION ALL
SELECT 2 AS N, 'A' AS C UNION ALL
SELECT 3 AS N, 'A' AS C UNION ALL
SELECT 4 AS N, 'B' AS C UNION ALL
SELECT 5 AS N, 'B' AS C UNION ALL
SELECT 6 AS N, 'B' AS C UNION ALL
SELECT 7 AS N, 'A' AS C UNION ALL
SELECT 8 AS N, 'A' AS C
),
T
AS (SELECT N,
C,
DENSE_RANK() OVER (ORDER BY N) -
DENSE_RANK() OVER (PARTITION BY C ORDER BY N) AS Grp
FROM YourTable)
SELECT COUNT(*),
C
FROM T
GROUP BY C,
Grp
ORDER BY MIN(N)
this will work for you...
SELECT
Total=COUNT(*), C
FROM
(
SELECT
NGroup = ROW_NUMBER() OVER (ORDER BY N) - ROW_NUMBER() OVER (PARTITION BY C ORDER BY N),
N,
C
FROM MyTable
)RegroupedTable
GROUP BY C,NGroup
Just for fun, without any SQL-specific functions and NOT assuming that the ID column is monotonically increasing:
WITH starters(name, minid, maxid) AS (
SELECT
a.name, MIN(a.id), MAX(a.id)
FROM
mytable a RIGHT JOIN
mytable b ON
(a.name <> b.name AND a.id < b.id)
WHERE
a.id IS NOT NULL
GROUP BY
a.name
),
both(name, minid, maxid) AS (
SELECT
name, minid, maxid
FROM
starters
UNION ALL
SELECT
name, MIN(id), MAX(id)
FROM
mytable
WHERE
id > (SELECT MAX(maxid) from starters)
GROUP BY
name
)
SELECT
COUNT(*), m.name, minid
FROM
both INNER JOIN
mytable m ON
id BETWEEN minid AND maxid
GROUP BY
m.name, minid
Result (ignore the midid column):
(No column name) name minid
3 A 1
3 B 4
2 A 7