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
Related
I'm using Microsoft SQL Server and I have a table shown below in my database:
Id groupName flag type
--------------------------------
1 aaa 0 0
2 aaa 1 0
3 aaa 0 0
4 bbb 0 0
5 bbb 0 0
6 bbb 0 0
I'd like to update the type column values based on the count of specific records in the same table.
Assuming that the records are grouped by their groupName, if a group has at least 1 record whose flag = 1, the typevalues of all the records in the same group should be 1, else 0.
In my case, I'd like to get the following output.
Id groupName flag type
--------------------------------
1 aaa 0 1
2 aaa 1 1
3 aaa 0 1
4 bbb 0 0
5 bbb 0 0
6 bbb 0 0
How can I do this with a SQL statement?
Edit
The following, of course, does not work.
UPDATE t1
SET type = CASE
WHEN ((SELECT COUNT(*) FROM tg) > 0)
THEN 1
ELSE 0
END
FROM [sampleDB].[dbo].[groups] t1
JOIN (SELECT t2.groupName, t2.flag
FROM [sampleDB].[dbo].[groups] t2) tg ON tg.groupName = t1.groupName
AND tg.flag = 1;
You can try the below -
UPDATE t
SET
type = case when cnt>=1 then 1 else 0 end
FROM
tablename t
INNER JOIN (select group_name, count(case when flag=1 then 1 end) as cnt from tablename
group by group_name)t1
ON t.group_name= t1.group_name
I would use window functions:
with toupdate as (
select g.*, max(flag) over (partition by groupname) as new_flag
from [sampleDB].[dbo].[groups] g
)
update toupdate
set flag = new_flag
where flag <> new_flag;
Note the where clause so only rows where the flag is changing are updated. SQL Server attempts to update row even when no values change, incurring overhead. The where clause saves most of this overhead.
You can simply do it by using a simple JOIN as:
UPDATE D
SET Type = 1
FROM Data D JOIN
(
SELECT GroupName
FROM Data
WHERE Flag = 1
) T ON D.GroupName = T.GroupName;
Here is a db-fiddle
This is the most performant way to solve this problem by using exists statement:
update t1
set type = 1
from table t1
where exists ( select 1
from table t2
where t1.groupname = t2.groupname
and flag = 1
)
This could be other option
;with data
As (
Select count(groupname) groupname
,max(flag) flag
,type
From Tablename
Group by type
Having count(groupname)>1
And max(flag)=1
)
Update c
Set type =1
From data c
I have a scenario where I need to fetch all the records within an ID for the same source. Given below is my input set of records
ID SOURCE CURR_FLAG TYPE
1 IBM Y P
1 IBM Y OF
1 IBM Y P
2 IBM Y P
2 TCS Y P
3 IBM NULL P
3 IBM NULL P
3 IBM NULL P
4 IBM NULL OF
4 IBM NULL OF
4 IBM Y ON
From the above settings, I need to select all the records with source as IBM within that same ID group.Within the ID group if there is at least one record with a source other than IBM, then I don't want any record from that ID group. Also, we need to fetch only those records where at least one record in that ID group with curr_fl='Y'
In the above scenario even though the ID=3 have a source as IBM, but there is no record with CURR_FL='Y', my query should not fetch the value.In the case of ID=4, it can fetch all the records with ID=4, as one of the records have value='Y'.
Also within the group which has satisfied the above condition, I need one more condition for source_type. if there are records with source_type='P', then I need to fetch only that record.If there are no records with P, then I will search for source_type='OF' else source_type='ON'
I have written a query as given below.But it's running for long and not fetching any results. Is there any better way to modify this query
select
ID,
SOURCE,
CURR_FL,
TYPE
from TABLE a
where
not exists(select 1 from TABLE B where a.ID = B.ID and source <> 'IBM')
and exists(select 1 from TABLE C where a.ID = C.ID and CURR_FL = 'Y') and
(TYPE, ID) IN (
select case type when 1 then 'P' when 2 then 'OF' else 'ON' END TYPE,ID from
(select ID,
max(priority) keep (dense_rank first order by priority asc) as type
from ( select ID,TYPE,
case TYPE
when 'P' then 1
when 'OF' then 2
when 'ON' then 3
end as priority
from TABLE where ID
in(select ID from TABLE where CURR_FL='Y') AND SOURCE='IBM')
group by ID))
I think you can just do a single aggregation over your table by ID and check for the yes flag as well as assert that no non IBM source appears. I do this in a CTE below, and then join back to your original table to return full matching records.
WITH cte AS (
SELECT
ID,
CASE WHEN SUM(CASE WHEN TYPE = 'P' THEN 1 ELSE 0 END) > 0
THEN 1
WHEN SUM(CASE WHEN TYPE = 'OF' THEN 1 ELSE 0 END) > 0
THEN 2
WHEN SUM(CASE WHEN TYPE = 'ON' THEN 1 ELSE 0 END) > 0
THEN 3 ELSE 4 END AS p_type
FROM yourTable
GROUP BY ID
HAVING
SUM(CASE WHEN CURR_FLAG = 'Y' THEN 1 ELSE 0 END) > 0 AND
SUM(CASE WHEN SOURCE <> 'IBM' THEN 1 ELSE 0 END) = 0
)
SELECT t1.*
FROM yourTable t1
INNER JOIN cte t2
ON t1.ID = t2.ID
WHERE
t2.p_type = 1 AND t1.TYPE = 'P' OR
t2.p_type = 2 AND t1.TYPE = 'OF' OR
t2.p_type = 3 AND t1.TYPE = 'ON';
In PostgreSQL, how can I merge multiple columns into one column with multiple rows?
The columns are all boolean, so I want to:
Filter for true values only
Replace the true value (1) with the name of the column (A, B or C)
I have this table:
ID | A | B | C
1 0 1 0
2 1 1 0
3 0 0 1
4 1 0 1
5 1 0 0
6 0 1 1
I want to get this table:
ID | Letter
1 B
2 A
2 B
3 C
4 A
4 C
5 A
6 B
6 C
I think you need something like this:
SELECT ID, 'A' as Letter FROM table WHERE A=1
UNION ALL
SELECT ID, 'B' as Letter FROM table WHERE B=1
UNION ALL
SELECT ID, 'C'as Letter FROM table WHERE C=1
ORDER BY ID, Letter
SELECT ID,
(CASE
WHEN TABLE.A = 1 then 'A'
WHEN TABLE.B = 1 then 'B'
WHEN TABLE.C = 1 then 'C'
ELSE NULL END) AS LETTER
from TABLE
You may try this.
insert into t2 select id, 'A' from t1 where A=1;
insert into t2 select id, 'B' from t2 where B=1;
insert into t2 select id, 'C' from t3 where C=1;
If you care about the order, then you can do this.
insert into t3 select id, letter from t2 order by id, letter;
W/o UNION
You can use a single query to get the desired output.Real time example
select id
,regexp_split_to_table((
concat_ws(',', case
when a = 0
then null
else 'a'
end, case
when b = 0
then null
else 'b'
end, case
when c = 0
then null
else 'c'
end)
), ',') l
from c1;
regexp_split_to_table() & concat_ws()
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.
Have the following Data in the table
Example Table
ID Value
1 a
1 b
1 c
2 a
2 b
2 c
3 a
3 b
I need to retrieve records having ID with only two values a and b.
So i am expecting only the Record with ID 3 .
Can anyone help me with the query
I guess you could do something like
select
ID,
sum(case when value = 'a' then 1
when value = 'b' then 1
else 3 end)
from
table1
group by id
having
sum (case when value = 'a' then 1
when value = 'b' then 1
else 3 end) =2
SQL Fiddle
That will work:
select x.id from
(
select id from mytable where value = 'a'
union all
select id from mytable where value = 'b'
) x
group by x.id
having COUNT(*) = 2
and not exists (select * from mytable t where t.id = x.id and value <> 'a' and value <> 'b')