I have a table that records status on course progress. A new record is added for each user/course comination when a course is started. That record is updated with a 'completed' status when the course is completed. I need to find the records for users who have never completed any courses.
Example Table:
User Course Status
A 1 S
A 2 C
B 1 S
C 2 S
D 2 C
C 3 S
I need a query that finds the following:
User Course Status
B 1 S
C 2 S
C 3 S
Any help is appreciated.
select user, course, status
from your_table
where user in
(
select user
from your_table
group by user
having sum(CASE WHEN status = 'C' THEN 1 ELSE 0 END) = 0
)
Select User, Course, Status from MyTable where User not in (Select Distinct User from MyTable where Status = 'C')
SELECT User,Course,Status FROM YourTable a
LEFT JOIN
(SELECT DISTINCT User FROM YourTable WHERE Status='C') CompletedAnything
ON a.User=CompletedAnything.User
WHERE COmpletedAnything.User IS NULL
Here's a SQL Fiddle that gives you what you want:
http://sqlfiddle.com/#!2/b6988/1
Query is this:
select User, Course, Status
from mytable
where User not in
(select distinct User from mytable where status = 'C' ans User is not null)
Related
So I have a list of users who every time they have a feature created, a new row with their ID will be created. I would like to exclude all users that have feature B enabled.
USER FEATURE
100 A
100 B
200 A
200 C
200 D
I can't do select USER from TABLE where FEATURE =! 'B' because that will still show USER 100. Any other solution?
Assuming all users are in this table, you can use aggregation:
select user
from t
group by user
having sum(case when feature = 'B' then 1 else 0 end) = 0;
If users are actually in another table, I would suggest:
select u.*
from users u
where not exists (select 1
from user_features uf
where uf.user = u.user and uf.feature = 'B'
);
with cte as (select user from table where feature ='B')
select user from table where user not in(select distinct user from cte);
I am trying to write a query from a table A which has 2 columns :
ID , STATUS
The Status can be PROCESSING, NOTPROCESSED, FAILED, SUCCESS
When a record is successfully processed, a new record is created in the DB with STATUS as PROCESSED and the ID is the same as the previous NOTPROCESSED record.
The Sample Records in DB would like :
1 NOTPROCESSED
2 PROCESSED
1 PROCESSED
3 NOTPROCESSED
4 NOTPROCESSED
2 PROCESSED
3 NOTPROCESSED
4 NOTPROCESSED
The records can appear as duplicate for NOTPROCESSED.
I have to query the records which are NOTPROCESSED i.e
3 NOTPROCESSED
4 NOTPROCESSED
Its getting quite confusing to write the query.
Can anyone help with the logic.
you may use not exists to get this output.
select distinct a.id,a.status
from table a
where a.status='NOTPROCESSED'
and not exists (select null
from table b
where b.id=a.id
and b.status='PROCESSED')
Group by the ids and take only those groups having no record of status PROCESSED
select id
from your_table
group by id
having sum(case when status = 'PROCESSED' then 1 else 0 end) = 0
or get only the ones with only one kind of status
having count(distinct status) = 1
or use alphabetically the highest status
having max(status) = 'NOTPROCESSED'
Here are a couple of options:
select distinct id from A where id not in (
select id from A where status = 'PROCESSED'
);
select distinct id from A natural left join (
select id from A where status = 'PROCESSED'
) as B where B.id is null;
You can use analytical function as follows:
select * from
(select t.*, count(case when status = 'PROCESSED' then 1 end)
over (partition by ID) as cnt
from your_table t) t
where status = 'NOTPROCESSED' and cnt = 0
I have write only DB log of changes I keep track of (or statuses) and values fluctuate between 1 and 2. In the below table; ID is identity column, STATUS is either 1 or 2 and USER is a user id.
If the latest status (i.e. max ID) for a given user is 1 then my query should return nothing (1 = good). So running the query against the data above would be just that.
Here comes my question: I want to query for all statuses of 2 since the last time it was 1. Here is sample data:
In this case my query should return 2 and 3 (ID) because these have statuses of 2 since the last time it was 1.
This next query should return nothing because the latest status for this user was switched to 1:
And finally this next one should return 5 (because the latest status is 2 since the last time it was 1):
There is no date field in this table, you can only work with MAX(ID) ... GROUP BY ID, USER
How can I do this? I'm using MS SQL 2016.
You can use windowed aggregates to do this
WITH T
AS (SELECT ID,
STATUS,
[USER],
MAX(CASE WHEN Status = 1 THEN ID END) OVER ( PARTITION BY [USER]) AS MaxS1
FROM YourTable)
SELECT *
FROM T
WHERE Status = 2
AND (ID > MaxS1 OR MaxS1 IS NULL)
Remove the OR MaxS1 IS NULL if you don't want the rows returned for users that have 2 and have never had 1 as a status
You can filter with not exists:
select t.*
from mytable t
where
t.status = 2
and not exists (
select 1 from mtyable t1 where t1.user = t.user and t1.id > t.id and t1.status = 1
)
This phrases as: all records with status 2 that have no following record (ie a record with the same user and a greatest id) with status = 1. If there are no records with status = 1 for a given user, all its records will be returned.
This can also be expressed with a left join antipattern:
select t.*
from mytable t
left join mytable t1 on t1.user = t.user and t1.id > t.id and t1.status = 1
where t1.id is null and t.status = 2
I want to compare data of a table with its other records. The count of rows with a specific condition has to match the count of rows without the where clause but on the same grouping.
Below is the table
-------------
id name time status
1 John 10 C
2 Alex 10 R
3 Dan 10 C
4 Tim 11 C
5 Tom 11 C
Output should be time = 11 as the count for grouping on time column is different when a where clause is added on status = 'C'
SELECT q1.time
FROM (SELECT time,
Count(id)
FROM table
GROUP BY time) AS q1
INNER JOIN (SELECT time,
Count(id)
FROM table
WHERE status = 'C'
GROUP BY time) AS q2
ON q1.time = q2.time
WHERE q1.count = q2.count
This is giving the desired output but is there a better and efficient way to get the desired result?
Are you looking for this :
select t.*
from table t
where not exists (select 1 from table t1 where t1.time = t.time and t1.status <> 'C');
However you can do :
select time
from table t
group by time
having sum (case when status <> 'c' then 1 else 0 end ) = 0;
If you want the times where the rows all satisfy the where clause, then in Postgres, you can express this as:
select time
from t
group by time
having count(*) = count(*) filter (where status = 'C');
Suppose I have a table with 2 columns (status and date) like the following:
status: U T U U L
date: 12 14 15 16 17
Can I (using only 1 SQL statement) count the number of distinct values in the status? That is:
count(U)=3
count(T)=1
count(L)=2
count(P)=0
Can I do this with 1 SQL query?
Note: I have static values in status. I can only have (U-T-L-P)
You need to use Group By:
SELECT Status, Count(Status)
FROM table
GROUP BY Status
This will not return P = 0 if P is not populated in the table. In your application logic you will need to check and if a certain status is not returned, it means there are no entries (i.e. 0).
SQL cannot query records that are not there.
This will return a row for every status and the count in the second column:
SELECT Status, COUNT(*) Cnt
FROM Tbl
GROUP BY Status
So it would return
Status Cnt
U 3
T 1
L 1
for your example (in no defined order). Use ORDER BY if you want to sort the results.
You can do this with a query which groups on your status column, e.g.
SELECT COUNT(*) as StatusCount, Status
FROM MyTable
GROUP BY Status
To get the zero for the status P, you have to do some devious stuff using a table that lists all the possible statuses.
SELECT COUNT(A.Status), B.Status
FROM AnonymousTable AS A RIGHT OUTER JOIN
(SELECT 'P' AS Status FROM Dual
UNION
SELECT 'U' AS Status FROM Dual
UNION
SELECT 'L' AS Status FROM Dual
UNION
SELECT 'T' AS Status FROM Dual
) AS B ON A.Status = B.Status
GROUP BY B.Status;
The 4-way UNION is one way of generating a list of values; your DBMS may provide more compact alternatives. I'm assuming that the table Dual contains just one row (as found in Oracle).
The COUNT(A.Status) counts the number of non-null values in A.Status. The RIGHT OUTER JOIN lists the row from B with Status = 'P' and joins it with a single NULL for the A.Status, which the COUNT(A.Status) therefore counts as zero. If you used COUNT(*), you'd get a 1 for the count.