I have a table displaying information for the top four ratings of produce in a store. I want to be able to find specific products in this rating table. Here is a structure of the table
----------------------------------------------------------------------------
sectId | product_code | product_category | consumer_raniking
10444 | 11222 | PRODUCE | RATING_1
10444 | 45555 | PRODUCE | RATING_1
10444 | 10005 | PR0DUCE | RATING_1
20555 | 11344 | PRODUCE | RATING_2
20555 | 94003 | PRODUCE | RATING_2
... and so on.
I wrote a rule to find inserted products which ins not working the way I want, i.e. to find the targetted fact that was inserted into the table. Here is the rule I put together:
rule "find by product codes rating_1"
when
$product_table: ProductRanking( $rank1: this.getProductCodesRankFirst())
$product1 : Product( this.product_code memberOf $rank1, $product_code: product_code )
$product2 : Product( this.product_code == 10444,this.product_code != $product_code ,$product_code2: product_code)
then
System.out.println("Found Products for product_codes "+$product_code+ " "+$product_code2 ) ;
end
Unfortunately, this returns 3 rows. I inserted into the session the product in row 2 i.e. product with ocde 45555 and it does find row 2. However, ir also brings in row 1 and row3.
I can see why it's doing that. It's because the skus are in the sectId with sectId 10444. However, I want to only bring in the row
that I inserted, which is sectionId(10444), product_code(45555). How can I achieve that?
I solved it by using a global to filter out the extra products. In the first line that brings the rankings, I eliminate the extra-matching products this way:
global ProductHelper productHelper
$product_table: ProductRanking( $rank1: productHelper.getProductCodesRankFirst(),
productCode != productHelper.getProductCodeFruitCategory() && productCode!=
productHelper.productCodeVegetableCategory())
The ProductHelper identifies the product codes I want to eliminate and hence the extra 2 products brought in are ignored, creating a single match. I'm sure there is a better way, but since I'm no expert, this is what I was able to come up with.
Related
In one table I have duplicate values that I would like to group and export only those fields where the value in the "published_at" field is the most up-to-date (the latest date possible). Do I understand it correctly as I use the MAX aggregate function the corresponding fields I would like to extract will refer to the max found or will it take the first found in the table?
Let me demonstrate you this on simple example (in real world example I am also joining two different tables). I would like to group it by id and extract all fields but only relating to the max published_at field. My query would be:
SELECT "t1"."id", "t1"."field", MAX("t1"."published_at") as "published_at"
FROM "t1"
GROUP By "t1"."id"
| id | field | published_at |
---------------------------------
| 1 | document1 | 2022-01-10 |
| 1 | document2 | 2022-01-11 |
| 1 | document3 | 2022-01-12 |
The result I want is:
1 - document3 - 2022-01-12
Also one question - why am I getting this error "ERROR: column "t1"."field" must appear in the GROUP BY clause or be used in an aggregate function". Can I use MAX function on string type column?
If you want the latest row for each id, you can use DISTINCT ON. For example:
select distinct on (id) *
from t
order by id, published_at desc
If you just want the latest row in the whole result set you can use LIMIT. For example:
select *
from t
order by published_at desc
limit 1
I have tried all the ways to delete the duplicate data except one but all of them are taking a lot of time to query. But JOINS was the only one that took very less time. But here the issue is I am able to use select query. but delete is not working in pgadmin4 (PostgreSQL 14.0). how will I be able to resolve this issue.
delete s1 FROM persons s1,
persons s2
where
s1.personid > s2.personid
AND s1.lastname = s2.lastname
order by personid desc
limit 100
It throws error saying "syntax error at or near "s1".
How can I solve this issue?
+-------------------------------------------+
|personid| firstname | lastname | email |
|------------------------------------------ |
| 1 shanny edward shane#123 |
| ------------------------------------------|
| 2 abc way abc#123 |
+-------------------------------------------+
You may use the following exists logic when deleting:
DELETE
FROM persons p1
WHERE EXISTS (
SELECT 1
FROM persons p2
WHERE p2.lastname = p1.lastname AND
p2.personid < p1.personid
);
The above logic will spare, for each last name group of records, a single record having the smallest personid value.
Ok, I deleted previous post and will try this again. I am sure I don't know the topic and I'm not sure if this is a loop or if I should use a stored function or how to get what I'm looking for. Here's sample data and expected output;
I have a single table A. Table has following fields; date created, unique person key, type, location.
I need a Postgres query that says for any given month(parameter, based on date created) and given a location(parameter based on location field), provide me fieds below where unique person key may be duplicated + or – 30 days from the date created within the month given for same type but all locations.
Example Data
Date Created | Unique Person | Type | Location
---------------------------------------------------
2/5/2017 | 1 | Admit | Hospital1
2/6/2017 | 2 | Admit | Hospital2
2/15/2017 | 1 | Admit | Hospital2
2/28/2017 | 3 | Admit | Hospital2
3/3/2017 | 2 | Admit | Hospital1
3/15/2017 | 3 | Admit | Hospital3
3/20/2017 | 4 | Admit | Hospital1
4/1/2017 | 1 | Admit | Hospital2
Output for the month of March for Hospital1:
DateCreated| UniquePerson | Type | Location | +-30days | OtherLoc.
------------------------------------------------------------------------
3/3/2017 | 2 | Admit| Hospital1 | 2/6/2017 | Hospital2
Output for the month of March for Hospital2:
None, because no one was seen at Hospital2 in March
Output for the month of March for Hospital3:
DateCreated| UniquePerson | Type | Location | +-30days | otherLoc.
------------------------------------------------------------------------
3/15/2017 | 3 | Admit| Hospital3 | 2/28/2017 | Hospital2
Version 1
I would use a WITH clause. Please, notice that I've added a column id that is a primary key to simplify the query. It's just to prevent the rows to be matched with themselves.
WITH x AS (
SELECT
id,
date_created,
unique_person_id,
type,
location
FROM
a
WHERE
location = 'Hospital1' AND
date_trunc('month', date_created) = date_trunc('month', '2017-03-01'::date)
)
SELECT
x.date_created,
x.unique_person_id,
x.type,
x.location,
a.date_created AS "+-30days",
a.location AS other_location
FROM
x
JOIN a
USING (unique_person_id, type)
WHERE
x.id != a.id AND
abs(x.date_created - a.date_created) <= 30;
Now a little bit of explanations:
First we select, let's say a reference data with a WITH clause. Think of it as a temporary table that we can reference in the main query. In given example it could be a "main visit" in given hospital.
Then we join "main visits" with other visits of the same person and type (JOIN condition) that happen in date difference of 30 days (WHERE condition).
Notice that the WITH query has the limits you want to check (location and date). I use date_trunc function that truncates the date to specified precision (a month in this case).
Version 2
As #Laurenz Albe suggested, there is no special need to use a WITH clause. Right, so here is a second version.
SELECT
x.date_created,
x.unique_person_id,
x.type,
x.location,
a.date_created AS "+-30days",
a.location AS other_location
FROM
a AS x
JOIN a
USING (unique_person_id, type)
WHERE
x.location = 'Hospital1' AND
date_trunc('month', x.date_created) = date_trunc('month', '2017-03-01'::date) AND
x.id != a.id AND
abs(x.date_created - a.date_created) <= 30;
This version is shorter than the first one but, in my opinion, the first is easier to understand. I don't have big enough set of data to test and I wonder which one runs faster (the query planner shows similar values for both).
I'm working on some application, and we're using postgres as our DB. I don't a lot of experience with SQL at all, and now i encountered a problem, that i can't find answer to.
So here's a problem:
We have privacy settings stored in separate table, and accessibility of each row of data depends on few rows of this privacy table.
Basically structure of privacy table is:
entityId | entityType | privacyId | privacyType | allow | deletedAt
-------------------------------------------------------------------
5 | user | 6 | user | f | //example entry
5 | user | 1 | user_all | t |
In two words, this settings mean, that user id5 allows to have access to his data to everybody except user id6.
So i get available data by query like:
SELECT <some_relevant_fields> FROM <table>
JOIN <join>
WHERE
(privacy."privacyId"=6 AND privacy."privacyType"='user' AND privacy.allow=true)
OR (
(privacy."privacyType"='user_all' AND privacy."deletedAt" IS NOT NULL)
AND
(privacy."privacyType"='user' AND privacy."privacyId"=6 AND privacy.allow!=false)
);
I know that this query is incorrect in this form, but i want you to get idea of what i try to achieve.
So it must check for field with its type/id and allow=true, OR check that user_all is not deleted(deletedAt field is null) and there is no field restricting access with allow=false to this user.
But it seems like postgres is chaining all expressions, so it overrides privacy."privacyType"='user_all' with 'user' at the end of expression, and returns no results, or returns data even if user "blocked", because 'user_all' exist.
Is there a way to write WHERE clause to return result if AND expression is true for 2 different rows, for example in code above: (privacy."privacyType"='user_all' AND privacy."deletedAt" IS NOT NULL) is true for one row AND (privacy."privacyType"='user' AND privacy."privacyId"=6 AND privacy.allow!=false) is true for other, or maybe check for absence of row with this values.
Is this what you want?
select <some_fields> from <table> where
privacyType='user_all' AND deletedAt IS NOT NULL
union
select <some_fields> from <table> where
privacyType='user' AND privacyId=6 AND allow<>'f';
You left join the table with itself and found what element doesnt have a match using the where.
SELECT p1.*
FROM privacy p1
LEFT JOIN privacy p2
ON p1."entityId" = p2."entityId"
AND p1."privacyType" = 'user_all'
AND p1."deletedAt" IS NULL
AND p2."privacyType"='user' AND
AND p2."privacyId"= 6
AND p2.allow!=false
WHERE
p2.privacyId IS NOT NULL
Given the following data set:
| page | sentence_ids |
|------|--------------|
| 1 | { 1, 2, 3 } |
| 2 | { 1, 2 } |
| 3 | { 3, 4 } |
I'd like to do a query that would return the pages where the sentence id occurred first. Preferably with sentence_ids only occurring once in the dataset and the least amount of pages. In this case:
| page | sentence_ids |
|------|--------------|
| 1 | { 1, 2, 3 } |
| 3 | { 4 } |
Is this even possible? The relation is denormalized because the pages can end up in the 10 thousands, and the sentences in the 100 thousands.
Right now we load all the pages with all the sentences and filter in the code. Terribly inefficient. Hope someone can help.
The only practical way* is to first unnest the array of sentence_ids and then pick the combination of page, sentence that matches the latter to the lowest page; you can do this with a window function by partitioning on the sentence and finding a rank after ordering by page. The record with rank=1 is the combination of interest. You then aggregate the result back into an array:
SELECT page, array_agg(sentence)
FROM (
SELECT page, sentence, rank() OVER (PARTITION BY sentence ORDER BY page) AS rnk
FROM (
SELECT page, unnest(sentence_ids) AS sentence
FROM page_sentences) p_s
) p_s_r
WHERE rnk = 1
GROUP BY page;
Given the size of your data this may not be a very fast solution but it is very likely to beat pulling all data and then filtering in code.
"Practical" is here loosely defined as "anything that avoids having to follow Craig's advice". (Sorry Craig...)