SQL - Count the occurence of one column value in another - sql

I have a table as shown below. Record key is unique per row
ID RECORD_KEY CONCAT_REJECT CONCAT_SUB
1 A34785 A123 23
1 B23845 R384 A123
1 H38959 Y345 A123
Expected Result
ID CONCAT_REJECT COUNT_REJECT_IN_SUB
1 A123 2
1 R384 0
1 Y345 0
How do I perform this count? I tried using COUNT(CONCAT_REJECT) over (PARTITION BY CONCAT_SUB). But it's not giving the desired result

Count concat_sub in the inner query and then do a left join with concat_reject to get final result. Here is the demo.
select
id,
concat_reject,
coalesce(total, 0) as count_reject_in_sub
from myTable m
left join(
select
concat_sub,
count(*) as total
from myTable
group by
concat_sub
) m1
on m.concat_reject = m1.concat_sub
output:
| id | concat_reject | count_reject_in_sub |
| --- | ------------- | ------------------- |
| 1 | A123 | 2 |
| 1 | R384 | 0 |
| 1 | Y345 | 0 |

Related

SQL UPDATE statement based on number of rows returned from SELECT subquery

I have a table with cols ID, and account type(int)
and I want to update account type to 3 for all rows, except one where given an ID there is more than one row with the same account type. so if I have
ID --- account_type
1 --- 2
1 --- 2
2 --- 1
2 --- 2
2 --- 3
I want to change one of the rows with id = 1 to have account type = 3 but leave the other one at 2 so I would like to return for the above example.
ID --- account_type
1 --- 2
1 --- 3
2 --- 1
2 --- 2
2 --- 3
I tried
UPDATE myTable
SET account_type = 3
WHERE 1 < (
SELECT COUNT(*)
FROM myTable
GROUP BY ID, account_type
HAVING COUNT(*) > 1);
but this updated every row in my db instead of just the one row with the duplicate account type so I know I did something wrong there. and this statement would set both rows with id=1 to have account_type =3 instead of just one row. How would I accomplish this?
EDIT:
I think I can fix the problem of only updating one row with:
UPDATE myTable p1
SET account_type = 3
WHERE 1 < (
SELECT COUNT(*)
FROM myTable p2
WHERE p1.primaryKey > p2.primaryKey
GROUP BY ID, account_type
HAVING COUNT(*) > 1);
but I'm still not sure why this updating every row in the db instead of the one with the duplicate account_type
So, we have table mytable:
| PrimaryKey | ID | account_type |
| ----------- | --- | ------------- |
| 1 | 1 | 2 |
| 2 | 1 | 2 |
| 3 | 2 | 1 |
| 4 | 2 | 2 |
| 5 | 2 | 3 |
and I think, this is Your update:
update mytable
set account_type = 3
where primarykey in (
select min(primarykey)
from mytable
group by id
)
and id not in (
select id
from mytable
where account_type = 3
);
this is the result:
| PrimaryKey | ID | account_type |
| ----------- | --- | ------------- |
| 1 | 1 | 3 |
| 2 | 1 | 2 |
| 3 | 2 | 1 |
| 4 | 2 | 2 |
| 5 | 2 | 3 |

Postgres SQL query to get the first row of distinct id

channels table
id | name
------------
1 | ABC
2 | XYZ
3 | MNO
4 | ASD
user_channels table
user_id | channel_id
----------------------
555 | 1
666 | 1
777 | 1
555 | 2
888 | 2
999 | 3
555 | 3
user_chats table
id | created_at | channel_id | content
---------------------------------------
2 | time 1 | 1 | Hello
3 | time 2 | 1 | Hi
4 | time 3 | 2 | Good day
5 | time 4 | 2 | Morning
I have these 3 tables in postgres SQL,
I want to write a sql query to get user_channels by user_id and it's latest message only (time 1 is oldest message) from user_chats table. How can I do that?
For example, for user_id = 555, the query should return
channel_id | content | created_at
---------------------------------------
1 | Hi | time 2
2 | Morning | time 4
3 | Null | Null
Use distinct on:
select distinct on (a.channel_id) a.*
from user_chats a
inner join user_channels l on l.channel_id = a.channel_id
where l.user_id = 555
order by a.channel_id, a.createt_at desc
If you want this for all users at once:
select distinct on (l.user_id, a.channel_id) l.user_id, a.*
from user_chats a
inner join user_channels l on l.channel_id = a.channel_id
order by l.user_id, a.channel_id, a.createt_at desc
You can use distinct on:
select distinct on (c.channel_id) c.channel_id, uc.content, uc.created_at
from user_channels c left join
user_chats uc
on uc.channel_id = c.channel_id
where c.user_id = ?
order by c.idchannel_id, uc.created_at desc;

Count the number of appearances of char given a ID

I have to perform a query where I can count the number of distinct codes per Id.
|Id | Code
------------
| 1 | C
| 1 | I
| 2 | I
| 2 | C
| 2 | D
| 2 | D
| 3 | C
| 3 | I
| 3 | D
| 4 | I
| 4 | C
| 4 | C
The output should be something like:
|Id | Count | #Code C | #Code I | #Code D
-------------------------------------------
| 1 | 2 | 1 | 1 | 0
| 2 | 3 | 1 | 0 | 2
| 3 | 3 | 1 | 1 | 1
| 4 | 2 | 2 | 1 | 0
Can you give me some advise on this?
This answers the original version of the question.
You are looking for count(distinct):
select id, count(distinct code)
from t
group by id;
If the codes are only to the provided ones, the following query can provide the desired result.
select
pvt.Id,
codes.total As [Count],
COALESCE(C, 0) AS [#Code C],
COALESCE(I, 0) AS [#Code I],
COALESCE(D, 0) AS [#Code D]
from
( select Id, Code, Count(code) cnt
from t
Group by Id, Code) s
PIVOT(MAX(cnt) FOR Code IN ([C], [I], [D])) pvt
join (select Id, count(distinct Code) total from t group by Id) codes on pvt.Id = codes.Id ;
Note: as I can see from sample input data, code 'I' is found in all of Ids. Its count is zero for Id = 3 in the expected output (in the question).
Here is the correct output:
DB Fiddle

How do I do an Oracle SQL update from select in a specific order?

I have a table with old values (some null) and new values for various attributes, all inserted at different add times throughout the months. I'm trying to update a second table with records with business month end dates. Right now, these records only contain the most recent new values for all month end dates. The goal is to create historical data by updating the previous month end values with the old values from the first table. I am a beginner and was able to come up with a query to update on one object where there was one entry from the first table. Now I am trying to expand the query to include multiple objects, with possible, multiple old values within the same month. I tried to use "order by" (since I need to make updates for a month in ascending order so it gets the latest value) but read that doesn't work with update statements without a subquery. So I tried my hand at making a more complicated query, without success. I am getting the following error: single-row subquery returns more than one row. Thanks!
TableA:
| ID | TYPE | OLD_VALUE | NEW_VALUE | ADD_TIME|
-----------------------------------------------
| 1 | A | 2 | 3 | 1/11/2019 8:00:00am |
| 1 | B | 3 | 4 | 12/10/2018 8:00:00am|
| 1 | B | 4 | 5 | 12/11/2018 8:00:00am|
| 2 | A | 5 | 1 | 12/5/2018 08:00:00am|
| 2 | A | 1 | 2 | 12/5/2019 09:00:00am|
| 2 | A | 2 | 3 | 12/5/2019 10:00:00am|
| 2 | B | 1 | 2 | 12/5/2019 10:00:00am|
TableB
| ID | MONTH_END | TYPE_A | TYPE_B |
-----------------------------------
| 1 | 1/31/19 | 3 | 5 |
| 1 | 12/31/18 | 3 | 5 |
| 1 | 11/30/18 | 3 | 5 |
| 2 | 12/31/18 | 3 | 2 |
| 2 | 11/30/18 | 3 | 2 |
Desired Output for TableB
| ID | MONTH_END | TYPE_A | TYPE_B |
-----------------------------------
| 1 | 1/31/19 | 3 | 5 |
| 1 | 12/31/18 | 2 | 5 |
| 1 | 11/30/18 | 2 | 3 |
| 2 | 12/31/18 | 3 | 2 |
| 2 | 11/30/18 | 5 | 2 |
My Query for Type A (Which I plan to adapt for Type B and execute as well for the desired output)
update TableB B
set b.type_a =
(
with aa as
(
select id, nvl(old_value, new_value) typea, add_time
from TableA
where type = 'A'
order by id, add_time ascending
)
select typea
from aa
where aa.id = b.id
and b.month_end <= aa.add_tm
)
where exists
(
with aa as
(
select id, nvl(old_value, new_value) typea, add_time
from TableA
where type = 'A'
order by id, add_time ascending
)
select typea
from aa
where aa.id = b.id
and b.month_end <= aa.add_tm
)
Kudo's for giving example input data and desired output. I found your question a bit confusing so let me rephrase to "Provide the last type a value from table a that is in the same month as the month end.
By matching on type and date of entry, we can get your answer. The "ROWNUM=1" is to limit result set to a single entry in case there is more than one row with the same add_time. This SQL is still a mess, maybe someone else can come up with a better one.
UPDATE tableb b
SET b.typea =
(SELECT old_value
FROM tablea a
WHERE LAST_DAY( TRUNC( a.add_time ) ) = b.month_end
AND TYPE = 'A'
AND add_time =
(SELECT MAX( add_time )
FROM tablea
WHERE TYPE = 'A' AND LAST_DAY( TRUNC( a.add_time ) ) = b.month_end)
AND ROWNUM = 1)
WHERE EXISTS
(SELECT old_value
FROM tablea a
WHERE LAST_DAY( TRUNC( a.add_time ) ) = b.month_end AND TYPE = 'A');

Count within the result set of a subquery

I have the following relations in my database:
Invoice InvoiceMeal
--------------------- ---------------------------
| InvoiceId | Total | | Id | InvoiceId | MealId |
--------------------- ---------------------------
| 1 | 22.32 | | 1 | 1 | 3 |
--------------------- ---------------------------
| 2 | 12.18 | | 2 | 1 | 2 |
--------------------- ---------------------------
| 3 | 27.76 | | 3 | 2 | 2 |
--------------------- ---------------------------
Meal Type
----------------------------------- -------------------
| Id | Name | TypeId | | Id | Name |
----------------------------------- -------------------
| 1 | Hamburger | 1 | | 1 | Meat |
----------------------------------- -------------------
| 2 | Soja Beans | 2 | | 2 | Vegetarian |
----------------------------------- -------------------
| 3 | Chicken | 2 |
-----------------------------------
What I want to query from the database is InvoiceId and Total of all Invoices which consist of at least two Meals where at least one of the Meals is of Type Vegetarian. I have the following SQL query and it works:
SELECT
i."Id", i."Total"
FROM
public."Invoice" i
WHERE
(SELECT COUNT(*)
FROM public."InvoiceMeal" im
WHERE im."InvoiceId" = i."Id" AND
(SELECT COUNT(*)
FROM public."Meal" m, public."Type" t
WHERE im."MealId" = m."Id" AND
m."TypeId" = t."Id" AND
g."Name" = 'Vegetarian') > 0
) >= 2;
My problem with this query is that I can not easily modify the condition that there must at least one vegetarien Meal. I want to be able, for example, to change it to at least two vegetarian meals. How can I achieve this with my query?
I would approach this by joining the tables together and using aggregation. The having clause can handle the conditions:
select i.Id, i.Total
from InvoiceMeal im join
Invoice i
on i.InvoiceId = im.InvoiceId join
Meal m
on im.mealid = m.mealid join
Type t
on m.typeid = t.typeid
group by i.Id, i.Total
having count(distinct im.mealid) >= 2 and
sum(case when t.name = 'Vegetarian' then 1 else 0 end) > 0;
I also see no reason to put double quotes around column names. That just makes the query harder to write and read.