sql Select id that matches combination of column - sql

Question

I have a token table
id | status
------------
1 | taken
1 | used
1 | deleted
2 | taken
2 | deleted
3 | taken
I need to count how many tokens are used ( in use or used).
If a token is taken and deleted without being used then it should not be counted.
So sql would be sth like
SELECT count(*) if the id's status is not (taken & deleted)
The desired number of used token in above example is 2 as
id 1 has been taken used and deleted -> count it
id 3 has been taken -> count it
id 2 has been taken and deleted without being used -> do not count it

Answer 1

A little bit verbose but efficient and still readable and maintainable:
SELECT COUNT(DISTINCT id)
FROM dbo.Token t
WHERE EXISTS
(
SELECT 1 FROM dbo.Token t1
WHERE t.id = t1.id
AND t1.status = 'used'
)
OR
(
EXISTS(
SELECT 1 FROM dbo.Token t1
WHERE t.id = t1.id
AND t1.status = 'taken'
)
AND NOT EXISTS(
SELECT 1 FROM dbo.Token t1
WHERE t.id = t1.id
AND t1.status = 'deleted'
)
)
Demo

Answer 2

Use aggregation and a having clause to get the list of eligible ids:
SELECT id
FROM token t
GROUP BY id
HAVING SUM(case when status = 'taken' then 1 else 0 end) > 0 or
SUM(case when status = 'used' then 1 else 0 end) > 0;
To get the count, use a subquery or CTE:
SELECT COUNT(*)
FROM (SELECT id
FROM token t
GROUP BY id
HAVING SUM(case when status = 'taken' then 1 else 0 end) > 0 or
SUM(case when status = 'used' then 1 else 0 end) > 0
) t

Answer 3

Try this:
SELECT SUM(CASE WHEN (CHARINDEX('used', data.status) > 0) OR (data.status = 'taken') THEN 1 ELSE 0 END) as [count]
FROM
(
SELECT DISTINCT id, (SELECT STUFF((SELECT Distinct ',' + status
FROM token a
WHERE a.id = b.id
FOR XML PATH (''))
, 1, 1, '')) as status
FROM token b
) data
Demo

Answer 4

You need to be able to take into account all three conditions, so a naive approach would be to just compare each three with a case statement:
WITH grouped as
(
select id from #uses group by id
)
select grouped.id,
used =
CASE WHEN used.id is not null THEN 'YES'
WHEN taken.id is not null and deleted.id is null THEN 'YES'
ELSE 'NO'
END
from grouped
left join #uses taken on grouped.id = taken.id
and taken.use_status = 'taken'
left join #uses used on grouped.id = used.id
and used.use_status = 'used'
left join #uses deleted on grouped.id = deleted.id
and deleted.use_status = 'deleted'
The case statement will stop whenever the condition is met, so you only need to WHEN's and an ELSE to meet the conditions.
This is a naive approach, though, and assumes that you only ever have one row per id and use status type. You'd have to do some additional work if that wasn't the case.

Answer 5

if token has been taken and used -> do not count it
SELECT
SUM(DECODE(status, 'taken', 1, 0)) +
SUM(DECODE(status, 'used', 1, 0)) -
SUM(DECODE(status, 'deleted', 1, 0))
FROM
token t
WHERE
status <> 'used' OR
EXISTS(SELECT 1 FROM token t2 WHERE t2.id = t.id and t2.status = 'deleted')
if token has been taken and used -> count it
SELECT
COUNT(1)
FROM
token t
WHERE
status = 'taken' AND
(
EXISTS(SELECT 1 FROM token t2 WHERE t2.id = t.id and t2.status = 'used') OR
NOT EXISTS(SELECT 1 FROM token t2 WHERE t2.id = t.id and t2.status = 'deleted')
)

Answer 6

Coming back to this question, one solution could be with using Pivot
SELECT COUNT(id)
FROM (
SELECT id, status FROM Token
) src
PIVOT
(
COUNT(status) FOR status IN ([taken], [used], [deleted])
) pvt
WHERE (taken = 1 AND deleted = 0)OR (used = 1)
DEMO