I've the below table
ID TYPE
--- ----
1 P
1 W
2 P
3 W
4 W
4 X
5 P
6 null
I need a new table to be created like the one below
ID Count of Type Code
-- -------------- -------
1 2 null
2 1 P
3 1 W
4 2 null
5 1 P
6 0 null
1st col ---> ID
2nd col ---> count of "type" for an ID
3rd col ---> if count(type) = 1 then TYPE
else null
Kindly help me in writing an ORACLE SQL query
You could use a subquery with the max function to get a value for the code and then use that in a case statement to get the value in your final query only when the count=1.
select id, cnt, case when cnt=1 then maxtype else null end as code
from
(select id, count(*) as cnt, max(type) as maxtype
from t1
group by id) t2
Related
Imagine this data.
Id
Type
1
A
1
B
1
B
2
A
3
B
I want to select table and ad two columns turning it to this. How can i do it? (In teradata)
Id
Type
Id with both A+B
Id with only A
1
A
1
0
1
B
1
0
1
B
1
0
2
A
0
1
3
B
0
0
I'm not familiar with teradata but in standard SQL next query should be working:
SELECT
T.*,
CASE WHEN Cnt = 2 THEN 1 ELSE 0 END AS BOTH_TYPES_PRESENT,
CASE WHEN Cnt = 1 AND Type = 'A' THEN 1 ELSE 0 END AS ONLY_A_PRESENT
FROM T
LEFT JOIN (
SELECT Id, COUNT(DISTINCT Type) Cnt FROM T WHERE Type IN ('A', 'B') GROUP BY Id
) CNT ON T.Id = CNT.Id;
SQL online editor
I have a table A:
entity_id name
------------------
1 Test1
2 Test2
3 Test3
4 Test4
5 Test5
6 Test6
I have a table B:
entity_id value1 value2
-----------------------------
1 10 20
1 15 30
2 10 25
1 9 45
3 null 1
2 45 50
3 20 null
I need to write a single query to select the entity_id and name from Table A and count the total occurrences for an entity_id of columns value1 and value2 from Table B and then the total of those column counts (null doesn't count).
So my output table would be:
entity_id name value1_count value2_count total_count
----------------------------------------------------------------------
1 Test1 3 3 6
2 Test2 1 2 3
3 Test3 1 1 2
4 Test4 0 0 0
5 Test5 0 0 0
6 Test6 0 0 0
I am having trouble summing the count of value1 and count of value2 and outputting that value in the total_count per unique entity_it.
This is the query I have so far:
SELECT DISTINCT a.entity_id, a.name
, count(b.value1) AS value1_count, count(b.value2) AS value2_count, sum(2) AS total_count
FROM a
LEFT JOIN b ON a.entity_id = b.entity_id
GROUP BY a.entity_id, a.name
I know that the sum(2) as total_count is incorrect and doesn't get me what I want.
SELECT entity_id, a.name
, COALESCE(b.v1_ct, 0) AS value1_count
, COALESCE(b.v2_ct, 0) AS value2_count
, COALESCE(b.v1_ct + b.v2_ct, 0) AS total_count
FROM a
LEFT JOIN (
SELECT entity_id, count(value1) AS v1_ct, count(value2) AS v2_ct
FROM b
GROUP BY 1
) b USING (entity_id);
db<>fiddle here
Aggregate first, join later. That's simpler and faster. See:
Query with LEFT JOIN not returning rows for count of 0
count() never produces NULL. Only the LEFT JOIN can introduce NULL values for counts in this query, so v1_ct and v2_ct are either both NULL or both NOT NULL. Hence COALESCE(v1_ct + v2_ct, 0) is ok. (Else, one NULL would nullify the other summand in the addition.)
try this :
WITH list AS
(
SELECT b.entity_id
, count(*) FILTER (WHERE b.value1 IS NOT NULL) OVER () AS value1_count
, count(*) FILTER (WHERE b.value2 IS NOT NULL) OVER () AS value2_count
FROM Table_B AS b
GROUP BY b.entity_id
)
SELECT a.entity_id, a.name
, COALESCE(l.value1_count, 0)
, COALESCE(l.value2_count,0)
, COALESCE(l.value1_count + l.value2_count, 0) AS total_count
FROM Table_A AS a
LEFT JOIN list AS l
ON a.entity_id = l.entity_id
I have a table with 3 columns that looks like this :
ID | obs_type | Value
1 A 0.1
1 A 0.2
1 B 0.4
2 B 0.5
2 C 0.2
2 C 0.3
3 B 0.1
I want to have the count of IDs with at least k observations in each group Type.
In the example above, if k = 2 (at least 2 observations of the same ID to be counted), I would like to have :
obs_type | count
A 1
B 0
C 1
As there is a single ID with two observations of type A and single ID with two observations of type C.
There are no ID with two observations of type B.
For k = 1, I just do :
SELECT obs_type, COUNT(DISTINCT ID ) FROM table_x GROUP BY obs_type;
But I'm looking for a solution that would work for arbitrary k.
Thanks !!!!
Do the aggregation in two steps:
k = 2 here:
select count(case when cnt >= 2 then cnt end), obs_type
from
(
select count(*) cnt, obs_type
from table_x
group by id, obs_type
) dt
group by obs_type
The derived table (subquery) returns:
cnt obs_type
================ ========
2 A
1 B
1 B
2 C
1 B
Then use a case expression to do conditional aggregation, and you'll get:
SQL>select count(case when cnt >= 2 then cnt end), obs_type
SQL&from
SQL&(
SQL& select count(*) cnt, obs_type
SQL& from table_x
SQL& group by id, obs_type
SQL&) dt
SQL&group by obs_type;
obs_type
==================== ========
1 A
0 B
1 C
3 rows found
I have a table as shown below:
group item rank
1 A 1
1 B 2
1 C 3
2 A 2
2 B 1
3 A 1
3 C 2
I want those groups data only, where item A has rank 1 as shown below:
group item rank
1 A 1
1 B 2
1 C 3
3 A 1
3 C 2
In group 2, A has rank 2, therefore not a part of output.
One way is using an IN clause
select *
from yourTable
where id in (select id from yourtable where item='A' and rank = 1)
you could use a subquery for get the involved id and the join
select * from my_table m
inner join (
select distinct id
from my_table
where item = 'A'
and rank = 1
) t on t.id = m.id
I'm trying get to find out if a row has the max value in a group. Here's really simple example:
Data
VoteCount LocationId UserId
3 1 1
4 1 2
3 2 2
4 2 1
Pseudo-query
select
LocationId,
sum(case
when UserId = 1 /* and has max vote count*/
then 1 else 0
end) as IsUser1Winner,
sum(case
when UserId = 2 /* and has max vote count*/
then 1 else 0
end) as IsUser2Winner
from LocationVote
group by LocationID
It should return:
LocationId IsUser1Winner IsUser2Winner
1 0 1
2 1 1
I also couldn't find a way to generate dynamic column names here. What would be the simplest way to write this query?
You could also do this using a Case statement
WITH CTE as
(SELECT
MAX(VoteCount) max_votes
, LocationId
FROM LocationResult
group by LocationId
)
SELECT
A.LocationId
, Case When UserId=1
THEN 1
ELSE 0
END IsUser1Winner
, Case when UserId=2
THEn 1
ELSE 0
END IsUser2Winner
from LocationResult A
inner join
CTE B
on A.VoteCount = B.max_votes
and A.LocationId = B.LocationId
Try this:
select *
from table t
cross apply (
select max(votes) max_value
from table ref
where ref.group = t.group
)votes
where votes.max_value = t.votes
but if your table is huge and has no propriate indexes performance may be poor
Another way is to get max values by groups into table variable or temp table and then join it to original table.