I have two table
table A
name id
ABC 1
PQR 2
XYZ 1
QWE 2
DFG 3
Another table
table B
id idname
1 stuart
2 bob
3 alex
expected output
id idname count
1 stuart 2
2 bob 2
3 alex 1
Iam using oracle 9i, Is it possible to obtain the expected result?
I have tried using distinct keyword but its not helping as it provides only the total count
That's simple. Join and count:
select b.id,
b.idname,
count(*) as cnt
from table_a a
join table_b b on a.id = b.id
group by b.id, b.idname;
If you need all the record from table b even if there is no corresponding row in table a, you can use an outer join:
select b.id,
b.idname,
count(a.id) as cnt
from table_a a
right join table_b b on a.id = b.id
group by b.id, b.idname;
Same can be achieved by using a left join:
select b.id,
b.idname,
count(a.id) as cnt
from table_b b
left join table_a a on a.id = b.id
group by b.id, b.idname;
Use JOIN to get data from both tables and use the aggregate function COUNT with GROUP BY.
Query
select t1.id, t1.idname, count(t2.name) as count
from TableB t1
left join TableA t2
on t1.id = t2.id
group by t1.id, t1.idname
order by count(t2.name) desc, t1.id;;
Related
I have 3 tables:
Basic
id
name
description
2
Name1
description2
3
Name2
description3
LinkA
id
linkA_ID
2
344
3
3221
2
6642
3
2312
2
323
LinkB
id
linkB_ID
2
8287
3
42466
2
616422
3
531
2
2555
2
8592
3
1122
2
33345
I want to get results as the table below:
id
name
description
linkA_count
linkB_count
2
Name1
description2
3
2
3
Name2
description3
5
3
my query:
SELECT
a.id
,a.name
,a.description
,COUNT(b.linkA_ID) AS linkA_count
,COUNT(c.linkB_ID) AS linkb_count
FROM
basic a
JOIN linkA b on (a.id = b.id)
JOIN linkb c on (a.id = c.id)
GROUP BY
a.id
,a.name
,a.description
Result from the query is count of linkA always same as linkB
A more traditional approach is to use "derived tables" (subqueries) so that the counts are performed before joins multiply the rows. Using left joins allows for all id's in basic to be returned by the query even if there are no related rows in either joined tables.
select
basic.id
, coalesce(a.LinkACount,0) LinkACount
, coalesce(b.linkBCount,0) linkBCount
from basic
left join (
select id, Count(linkA_ID) LinkACount from LinkA group by id
) as a on a.id=basic.id
left join (
select id, Count(linkB_ID) LinkBCount from LinkB group by id
) as b on b.id=basic.id
Try This (using SubQuery)
SELECT
basic.id
,basic.name
,basic.description
,(select Count(linkA_ID) from LinkA where LinkA.id=basic.id) as LinkACount
,(select Count(linkB_ID) from LinkB where LinkB.id=basic.id) as LinkBCount FROM basic
Method 2 (Try CTE)
with a as(select id,Count(linkA_ID)LinkACount from LinkA group by id)
, b as (select id,Count(linkB_ID)LinkBCount from LinkB group by id)
select basic.id,a.LinkACount,b.linkBCount
from basic
join a on (a.id=basic.id)
join b on (b.id=basic.id)
If you only select from your table you see why your query cannot work.
SELECT
*
FROM
basic a
JOIN linkA b on (a.id = b.id)
JOIN linkb c on (a.id = c.id)
WHERE a.ID = 3
=> just use distinct in your count
SELECT
a.id
,a.name
,a.description
,COUNT(DISTINCT(b.linkA_ID)) AS linkA_count
,COUNT(DISTINCT(c.linkB_ID)) AS linkb_count
FROM
basic a
JOIN linkA b on (a.id = b.id)
JOIN linkb c on (a.id = c.id)
GROUP BY
a.id
,a.name
,a.description
I have two datasets in Oracle Table1 and Table2.
When I run this:
SELECT A.ID, B.NUM_X
FROM TABLE1 A
LEFT JOIN TABLE2 B ON A.ID=B.ID
WHERE B.BOOK = 1
It returns this.
ID NUM_X
1 10
1 5
1 9
2 2
2 1
3 20
3 11
What I want are the DISTINCT ID where NUM_X is the MAX value, something like this:
ID NUM_x
1 10
2 2
3 20
You can use aggregation:
SELECT A.ID, MAX(B.NUM_X)
FROM TABLE1 A LEFT JOIN
TABLE2 B
ON A.ID = B.ID
WHERE B.BOOK = 1
GROUP BY A.ID;
If you wanted additional columns, I would recommend window functions:
SELECT A.ID, MAX(B.NUM_X)
FROM TABLE1 A LEFT JOIN
(SELECT B.*,
ROW_NUMBER() OVER (PARTITION BY ID ORDER BY NUM_X DESC) as seqnum
FROM TABLE2 B
) B
ON A.ID = B.ID AND B.seqnum = 1
WHERE B.BOOK = 1
GROUP BY A.ID;
TableA:
Userid sessionid domain_value tag
---------------------------------
1 20 amex bank
1 40 visa bank
2 10 citibank bank
2 20 amex bank
2 30 amex bank
TableB:
Userid sessionid(min) sessionid(max)
------------------------------------
1 20 40
2 10 30
3
4
5
How to retrieve all the rows from TableA based on values in TableB?
select *
from TableA a
inner join TableB b on a.userid = b.userid
where a.sessionid between (select b.[sessionid(min)] from TableB b)
and (select b.sessionid(max)] from TableB b)
assumin table B with these column name
Userid, sessionid_min, sessionid_max,
try using just between column_fom_min and column_for_max
select *
from TableA a
inner join TableB b on a.userid = b.userid
where a.sessionid between b.sessionid_min
and b.sessionid_max
How to retrieve all the rows from TableA based on values in TableB?
In order to retrieve rows from TableA, select from TableA. If you want to filter based on values in TableB, place an according WHEREclause in the query. There is no need to join here.
select *
from tablea a
where exists
(
select null
from tableb b
where a.sessionid between b.sessionid_min and b.sessionid_max
)
order by userid, sessionid;
(You can achieve the same with a join, but the intention would not be as clear from reading the query.)
You may try this
select t.Userid ,
(select min(sessionid) from TableA as tb on tb.Userid =t.Userid ) as Min,
(select max(sessionid) from TableA as tb on tb.Userid =t.Userid ) as Max
from TableA as t group by t.Userid
I have 2 tables, Table A and Table B. I need to return all records from Table A, but I need COL_A replaced with latest value of COL_A from TABLE_B if the ID exist.
TABLE_A TABLE_B
ID COL_A A_ID COL_A CREATED_DATE
1 AAA 1 AA1 1/11/18
2 BBB 1 AA2 1/12/18
3 CCC 3 CC1 1/12/18
Expected output:
ID COL_A
1 AA2
2 BBB
3 CC1
I'm able to execute the following with Oracle 12c, but not on 11g. Need help on how to query this for 11g?
select ID,
NVL((select * from (select FIRST_VALUE(COL_A) OVER (ORDER BY CREATED_DATE DESC) from TABLE_B WHERE A_ID=A.ID) where ROWNUM=1),COL_A) AS COL_A
from TABLE_A A
You are missing the join between 2 tables and a subquery to check for max date:
select a.ID, NVL(b.col_a, a.col_a)
from TABLE_A a left outer join TABLE_B b
on a.id = b.a_id
and b.created_date =
(select max(innerB.createdDate) from Table_B innerB where innerB.a_id = a.id);
Try this and let me know in case of error
I would be inclined to use window functions:
select a.id, coalesce(b.col_a, a.col_a) as col_a
from a left join
(select b.*,
row_number() over (partition by b.a_id order by b.created_date) as seqnum
from b
) b
on b.a_id = a.id and b.seqnum = 1;
This seems much simpler than a version that uses a join and a correlated subquery.
I have TableA in a many-to-many relationship with TableC via TableB. That is,
TableA TableB TableC
id | val fkeyA | fkeyC id | data
I wish the do select sum(val) on TableA, grouping by the relationship(s) to TableC. Every entry in TableA has at least one relationship with TableC. For example,
TableA
1 | 25
2 | 30
3 | 50
TableB
1 | 1
1 | 2
2 | 1
2 | 2
2 | 3
3 | 1
3 | 2
should output
75
30
since rows 1 and 3 in Table have the same relationships to TableC, but row 2 in TableA has a different relationship to TableC.
How can I write a SQL query for this?
SELECT
sum(tableA.val) as sumVal,
tableC.data
FROM
tableA
inner join tableB ON tableA.id = tableB.fkeyA
INNER JOIN tableC ON tableB.fkeyC = tableC.id
GROUP by tableC.data
edit
Ah ha - I now see what you're getting at. Let me try again:
SELECT
sum(val) as sumVal,
tableCGroup
FROM
(
SELECT
tableA.val,
(
SELECT cast(tableB.fkeyC as varchar) + ','
FROM tableB WHERE tableB.fKeyA = tableA.id
ORDER BY tableB.fkeyC
FOR XML PATH('')
) as tableCGroup
FROM
tableA
) tmp
GROUP BY
tableCGroup
Hm, in MySQL it could be written like this:
SELECT
SUM(val) AS sumVal
FROM
( SELECT
fkeyA
, GROUP_CONCAT(fkeyC ORDER BY fkeyC) AS grpC
FROM
TableB
GROUP BY
fkeyA
) AS g
JOIN
TableA a
ON a.id = g.fkeyA
GROUP BY
grpC
SELECT sum(a.val)
FROM tablea a
INNER JOIN tableb b ON (b.fKeyA = a.id)
GROUP BY b.fKeyC
It seems that is it needed to create a key_list in orther to allow group by:
75 -> key list = "1 2"
30 -> key list = "1 2 3"
Because GROUP_CONCAT don't exists in T-SQL:
WITH CTE ( Id, key_list )
AS ( SELECT TableA.id, CAST( '' AS VARCHAR(8000) )
FROM TableA
GROUP BY TableA.id
UNION ALL
SELECT TableA.id, CAST( key_list + ' ' + str(TableB.id) AS VARCHAR(8000) )
FROM CTE c
INNER JOIN TableA A
ON c.Id = A.id
INNER join TableB B
ON B.Id = A.id
WHERE A.id > c.id --avoid infinite loop
)
Select
sum( val )
from
TableA inner join
CTE on (tableA.id = CTE.id)
group by
CTE.key_list