Join with table - sql

Say I have two tables as below where Table A has columns name and type where each name may appear many times and with different type and Table B has unique code, name and sum.
Table A
John Type1
Mark Type2
John Type1
Mark Type3
John Type4
Paul Type5
Table B
1 John 20
2 Mark 33
3 Paul 22
4 Mark 55
5 John 46
Now what I want is something like this:
Table C
1 John 20 Type1
2 Mark 33 Type2
3 Paul 22 Type5
4 Mark 55 Type2
5 John 46 Type1
Normally Table A should contain unique entries with one type for each name and I could do a right join Table B on name to get what I want. But now if I do right join I get duplicate entries on Table C because name has duplicates types in Table A. How do I solve this?

Try this
WITH TableAA
AS
(
SELECT ROW_NUMBER() OVER(PARTITION BY NAME ORDER BY NAME,TYPE) RN
,name
,type
FROM TableA
)
SELECT
B.*
,(
SELECT type from TableAA A WHERE A.name= B.name AND A.RN=
ISNULL(NULLIF((SELECT COUNT(1) FROM TableB C WHERE C.NAME=B.name
and C.no < B.no),0),1)
) AS Type
FROM
TableB B
SQLFiddle Demo

You can try this :
SELECT A.*,B.TYPE
FROM dbo.TABLE_2 A RIGHT JOIN
(
SELECT DISTINCT(NAME),MIN(TYPE)TYPE
FROM TABLE_1
GROUP BY NAME
) B ON A.NAME=B.NAME
ORDER BY CODE ASC
TABLE_1= TABLE A
TABLE_2= TABLE B

Related

how to execute query for each row result of another query

I have 2 tables , one stores IDs and another logs for each ID , i would like to get sum of log for each ID and ID number from these 2 tables
A B
------- -------------
ID ID_C LOG
1 1 15
2 1 30
3 4 44
4 2 14
5 3 88
3 10
2 10
for getting sum query is
SELECT SUM(LOG) FROM B WHERE ID_C ='2' ;
notice ID and ID_C are same but name is different in tables
and for getting all ids available query is
SELECT ID FROM A ;
I would like to get the following table result
result
--------------------
ID SUM
1 45
4 44
2 24
3 98
I tried
SELECT SUM(LOG) FROM B WHERE ID_C in (SELECT ID FROM A ) ;
but it result in sum of all IDs
It looks like you just need a join aggregation here:
SELECT a.ID, SUM(b.LOG) AS SUM
FROM A a
INNER JOIN B b
ON b.ID_C = a.ID
GROUP BY a.ID
ORDER BY a.ID;
Note that the inner join will also remove ID values from the A table which no entries whatsoever in the B table, which seems to be the behavior you want.
you should use inner join and GROUP BY:
SELECT A.ID as ID, SUM(LOG) AS SumLOG
FROM A inner join B ON A.ID = B.ID_C
GROUP BY A.ID
if you needed can use where for ID filter.

How to join 2 tables with no common column in sql

eg
Names
id | name
1 abc
2 efg
Area
id | areaName
3 area1
4 area2
The query should return
id | name | areaid
1 abc 3
1 abc 4
2 efg 3
2 efg 4
This should give the ecpected result:
select a.id, a.name, b.id from names,area
When you want to join all records from table A to all records from table B (i.e. get a Cartesian product, you can use CROSS JOIN:
SELECT Names.id, Names.name, Area.areaid
FROM Names
CROSS JOIN Area
ORDER BY Names.id, Area.areaid

INSERT rows by Comparing Two Tables

I have two tables like this:
ID Name Value
----------------------
1 Book1 A
2 Book2 B
3 Book3 C
Name
----------------------
Book4
Book5
I'm trying to write query to insert rows in the first table so it becomes:
ID Name Value
----------------------
1 Book1 A
2 Book2 B
3 Book3 C
1 Book4 NULL
2 Book4 NULL
3 Book4 NULL
1 Book5 NULL
2 Book5 NULL
3 Book5 NULL
I can't get it to work with this query:
SELECT a.ID,
b.Name,
a.Value
FROM table1 a
LEFT JOIN (SELECT Name FROM table2) b ON a.Name = b.Name
I also tried CROSS JOIN but still couldn't quite get it. Any help will be appreciated.
For this case I will name TableA your first table and TableB the one with only names. But next time try to provide some meaningfull names.
INSERT INTO TableA
SELECT A.ID, B.Name, Null
FROM
(
SELECT DISTINCT ID
FROM TableA
) A, TableB B

Get the max value of a column from set of rows

I have a table like this
Table A:
Id Count
1 4
1 16
1 8
2 10
2 15
3 18
etc
Table B:
1 sample1.file
2 sample2.file
3 sample3.file
TABLE C:
Count fileNumber
16 1234
4 2345
15 3456
18 4567
and so on...
What I want is this
1 sample1.file 1234
2 sample2.file 3456
3 sample3.file 4567
To get the max value from table A I used
Select MAX (Count) from A where Id='1'
This works well but my problem is when combining data with another table.
When I join Table B and Table A, I need to get the MAX for all Ids and in my query I dont know what Id is.
This is my query
SELECT B.*,C.*
JOIN A on A.Id = B.ID
JOIN C on A.id = B.ID
WHERE (SELECT MAX(COUNT)
FROM A
WHERE Id = <what goes here????>)
To summarise, what I want is Values from Table B, FileNumber from Table c (where the count is Max for ID from table A).
UPDATE: COrrecting table C above. Looks like I need Table A.
I think this is the query you're looking for:
select b.*, c.filenumber from b
join (
select id, max(count) as count from a
group by id
) as NewA on b.id = NewA.id
join c on NewA.count = c.count
However, you should take into account that I don't get why for id=1 in tableA you choose the 16 to match against table C (which is the max) and for id=2 in tableA you choose the 10 to match against table C (which is the min). I assumed you meant the max in both cases.
Edit:
I see you've updated tableA data. The query results in this, given the previous data:
+----+---------------+------------+
| ID | FILENAME | FILENUMBER |
+----+---------------+------------+
| 1 | sample1.file | 1234 |
| 2 | sample2.file | 3456 |
| 3 | sample3.file | 4567 |
+----+---------------+------------+
Here is a working example
Using Mosty’s working example (renaming the keyword count to cnt for a column name), this is another approach:
with abc as (
select
a.id,
a.cnt,
rank() over (
partition by a.id
order by cnt desc
) as rk,
b.filename
from a join b on a.id = b.id
)
select
abc.id, abc.filename, c.filenumber
from abc join c
on c.cnt = abc.cnt
where rk = 1;
select
PreMax.ID,
B.FileName,
C2.FileNumber
from
( select C.id, max( C.count ) maxPerID
from TableC C
group by C.ID
order by C.ID ) PreMax
JOIN TableC C2
on PreMax.ID = C2.ID
AND PreMax.maxPerID = C2.Count
JOIN TableB B
on PreMax.ID = B.ID

Tricky SQL - Select non-adjacent numbers

Given this data on SQL Server 2005:
SectionID Name
1 Dan
2 Dan
4 Dan
5 Dan
2 Tom
7 Tom
9 Tom
10 Tom
How would I select records where the sectionID must be +-2 or more from another section for the same name.
The result would be:
1 Dan
4 Dan
2 Tom
7 Tom
9 Tom
Thanks for reading!
SELECT *
FROM mytable a
WHERE NOT EXISTS
(SELECT *
FROM mytable b
WHERE a.Name = b.Name
AND a.SectionID = b.SectionID + 1)
Here's LEFT JOIN variant of Anthony's answer (removes consecutive id's from the results)
SELECT a.*
FROM mytable a
LEFT JOIN mytable b ON a.Name = b.Name AND a.SectionID = b.SectionID + 1
WHERE b.SectionID IS NULL
EDIT: Since there is another interpretation of the question (simply getting results where id's are more than 1 number apart) here is another attempt at an answer:
WITH alternate AS (
SELECT sectionid,
name,
EXISTS(SELECT a.sectionid
FROM mytable b
WHERE a.name = b.name AND
(a.sectionid = b.sectionid-1 or a.sectionid = b.sectionid+1)) as has_neighbour,
row_number() OVER (PARTITION by a.name ORDER BY a.name, a.sectionid) as row_no
FROM mytable a
)
SELECT sectionid, name
FROM alternate
WHERE row_no % 2 = 1 OR NOT(has_neighbour)
ORDER BY name, sectionid;
gives:
sectionid | name
-----------+------
1 | Dan
4 | Dan
2 | Tom
7 | Tom
9 | Tom
Logic: if a record has neighbors with same name and id+/-1 then every odd row is taken, if it has no such neighbors then it gets the row regardless if it is even or odd.
As stated in the comment the condition is ambiguous - on start of each new sequence you might start with odd or even rows and the criteria will still be satisfied with different results (even with different number of results).