I have a table like below where I need to query a count of how many times each ID went from specifically 'Waste Sale' in one value to 'On Stop' in the very next value based on ascending date and if there are no instances of this, the count will be 0
ID
Stage name
Stage Changed Date
1
Waste Sale
06-05-2022
1
On Stop
08-06-2022
1
Cancelled
09-02-2022
2
Waste Sale
06-05-2022
2
On Stop
07-05-2022
2
Waste Sale
08-06-2022
2
On Stop
10-07-2022
3
Cancelled
10-07-2022
3
On Stop
11-07-2022
The result I would be looking for based on the above table would be something like this:
ID
Count of 'Waste Sales to On Stops'
1
1
2
2
3
0
ID 1 having a count of 1 because there was one instance of 'Waste Sale' changing to 'On Stop' in the very next value based on date range
ID 3 having a count of 0 because even though the stage name changed to 'On Stop' the previous value based on date range wasn't 'Waste Sale'.
I have a hunch I would have to use something like LEAD() and GROUP BY/ ORDER BY but since I'm so new to SQL would really appreciate some help on the specific syntax and coding. Any version of SQL is okay.
We can use window function lead to take a peek at the next value of the query result.
select distinct id,
(
select count(*)
from
(
select *,
lead(stage_name)
over(
partition by id
order by stage_changed_date)
as stage_next
from sales s2
) s3
where s3.id = s1.id
and s3.stage_name = 'waste sale'
and s3.stage_next = 'on stop'
) as count_of_waste_sales_to_on_stop
from sales s1
order by id;
Query above uses lead(stage_name) over(partition by id order by stage_changed_date) to get the next stage_name in the query result while segregating it by id and order it based on stage_changed_date. Check the query on DB Fiddle.
Note:
I have no experience in zoho, so i'm unsure if the query will 100% works or not. They said it supported ansi-sql, however there might some differences with MySQL due to reasons.
The column names are not the exact same with op question due to testing only done using DB Fiddle.
There might better query out there waiting to be written.
Objective
I have a list of payment records that contain account_uuid, price, type & created_at. I need to get a list of the latest payment record specific to each account_uuid where the type = 0.
What I have tried
My first attempt was to ORDER BY on created_at to ensure the latest row was last, then to GROUP BY on account_uuid. The issue is that I would have to add both account_uuid and created_at to the GROUP BY expression which would include multiple records for the account_uuid as it will only group rows when both account_uuid and created_at are the same, which is never.
My second attempt was to SELECT DISTINCT ON account_uuid. This didn't work for the same reason above as it complains I must include my ORDER BY column in my DISTINCT ON expression which would yield the same result.
Sample Data
account_uuid
price
type
created_at (↑)
aa4dd27e-b72a-40fd-bdab-94810e585734
8.96
0
1649840899215
5c5625af-65e5-43d3-a39d-b896cd4d02a3
14.58
0
1649841117203
aa4dd27e-b72a-40fd-bdab-94810e585734
null
2
1649843706217
d8a106f9-dbf2-42f1-ac6b-a17e88700fab
3.939
0
1650434747192
aa4dd27e-b72a-40fd-bdab-94810e585734
14.58
0
1650438658596
Sample Result (Desired)
account_uuid
price
type (=0)
created_at (↑)
5c5625af-65e5-43d3-a39d-b896cd4d02a3
14.58
0
1649841117203
d8a106f9-dbf2-42f1-ac6b-a17e88700fab
3.939
0
1650434747192
aa4dd27e-b72a-40fd-bdab-94810e585734
14.58
0
1650438658596
Problem / Question
What I am trying to achieve is the sample result which you can see returns only the latest row for the account_uuid where type is 0 and created_at is ascending. Best case I would like to do it without any joins/subqueries but am happy for just getting it working.
Thank You
Edit: A simpler solution would be:
select distinct on (account_uuid)
max(created_at)
,price
,type
,account_uuid
from tableName
where type = 0
group by price,type,account_uuid
You can achieve this in Postgres without using join/sub-queries by using a combination of DISTINCT ON and window functions. This assumes that you truly want the "latest row where type = 0" and not "If the latest row = 0".
select distinct on (account_uuid)
max(created_at) over (partition by account_uuid order by created_at desc)
,price
,type
,account_uuid
from tableName
where type = 0
Fiddle here
You need select using ROW_NUMBER() in a sub query and then in the outer where statement you select RN = 1
There are many code examples of using ROW_NUMBER() if you search for it.
i need help for creating a query
Current situation:
The output table contains Ids and levels. Each Id can appear several times.
Problem:
Now I want to know if level 1 appears for an id, if so I want to mark it as number 1. If an Id has only level 2 or zero just mark it as number 0.
The output can be taken from the table below.
Use aggregation:
select id,
max(case when level = 1 then 1 else 0 end) as flag
from t
group by id;
I have data which contains 1000+ lines and in this it contains errors people make. I have added a extra column and would like to find all duplicate Rev Names and give the first one a 1 and all remaining duplicates a 0. When there is no duplicate, it should be a 1. The outcome should look like this:
RevName ErrorCount Duplicate
Rev5588 23 1
Rev5588 67 0
Rev5588 7 0
Rev5588 45 0
Rev7895 6 1
Rev9065 4 1
Rev5588 1 1
I have tried CASE WHEN but its not giving the first one a 1, its giving them all zero's.
Thanks guys, I am pulling out my hair here trying to get this done.
You could use a case expression over the row_number window function:
SELECT RevName,
Duplicate,
CASE ROW_NUMER() OVER (PARTITION BY RevName
ORDER BY (SELECT 1)) WHEN 1 THEN 1 ELSE 0 END AS Duplicate
FROM mytable
SQL tables represent unordered sets. There is no "first" of anything, unless a column specifies the ordering.
Your logic suggests lag():
select t.*,
(case when lag(revname) over (order by ??) = revname then 0
else 1
end) as is_duplicate
from t;
The ?? is for the column that specifies the ordering.
We have a table with following data
Id,ItemId,SeqNumber;DateTimeTrx
1,100,254,2011-12-01 09:00:00
2,100,1,2011-12-01 09:10:00
3,200,7,2011-12-02 11:00:00
4,200,5,2011-12-02 10:00:00
5,100,255,2011-12-01 09:05:00
6,200,3,2011-12-02 09:00:00
7,300,0,2011-12-03 10:00:00
8,300,255,2011-12-03 11:00:00
9,300,1,2011-12-03 10:30:00
Id is an identity column.
The sequence for an ItemId starts from 0 and goes till 255 and then resets to 0. All this information is stored in a table called Item. The order of sequence number is determined by the DateTimeTrx but such data can enter any time into the system. The expected output is as shown below-
ItemId,PrevorNext,SeqNumber,DateTimeTrx,MissingNumber
100,Previous,255,2011-12-01 09:05:00,0
100,Next,1,2011-12-01 09:10:00,0
200,Previous,3,2011-12-02 09:00:00,4
200,Next,5,2011-12-02 10:00:00,4
200,Previous,5,2011-12-02 10:00:00,6
200,Next,7,2011-12-02 11:00:00,6
300,Previous,1,2011-12-03 10:30:00,2
300,Next,255,2011-12-03 16:30:00,2
We need to get those rows one before and one after the missing sequence. In the above example for ItemId 300 - the record with sequence 1 has entered first (2011-12-03 10:30:00) and then 255(2011-12-03 16:30:00), hence the missing number here is 2. So 1 is previous and 255 is next and 2 is the first missing number. Coming to ItemId 100, the record with sequence 255 has entered first (2011-12-02 09:05:00) and then 1 (2011-12-02 09:10:00), hence 255 is previous and then 1, hence 0 is the first missing number.
In the above expected result, MissingNumber column is the first occuring missing number just to illustrate the example.
We will not have a case where we would have a complete series reset at one time i.e. it can be either a series rundown from 255 to 0 as in for itemid 100 or 0 to 255 as in ItemId 300. Hence we need to identify sequence missing when in ascending order (0,1,...255) or either in descending order (254,254,0,2) etc.
How can we accomplish this in a t-sql?
Could work like this:
;WITH b AS (
SELECT *
,row_number() OVER (ORDER BY ItemId, DateTimeTrx, SeqNumber) AS rn
FROM tbl
), x AS (
SELECT
b.Id
,b.ItemId AS prev_Itm
,b.SeqNumber AS prev_Seq
,c.ItemId AS next_Itm
,c.SeqNumber AS next_Seq
FROM b
JOIN b c ON c.rn = b.rn + 1 -- next row
WHERE c.ItemId = b.ItemId -- only with same ItemId
AND c.SeqNumber <> (b.SeqNumber + 1)%256 -- Seq cycles modulo 256
)
SELECT Id, prev_Itm, 'Previous' AS PrevNext, prev_Seq
FROM x
UNION ALL
SELECT Id, next_Itm ,'Next', next_Seq
FROM x
ORDER BY Id, PrevNext DESC
Produces exactly the requested result.
See a complete working demo on data.SE.
This solution takes gaps in the Id column into consideration, as there is no mention of a gapless sequence of Ids in the question.
Edit2: Answer to updated question:
I updated the CTE in the query above to match your latest verstion - or so I think.
Use those columns that define the sequence of rows. Add as many columns to your ORDER BY clause as necessary to break ties.
The explanation to your latest update is not entirely clear to me, but I think you only need to squeeze in DateTimeTrx to achieve what you want. I have SeqNumber in the ORDER BY additionally to break ties left by identical DateTimeTrx. I edited the query above.