I need to do a inner join, where i Get a concrete number of "parent elements" but all it's relations.
If i have the table Agent:
IdAgent | Name
1 | Agent1
2 | Agent2
And the table Econ
IdEcon IdAgent Number
1 | 1 | number1
2 | 2 | number21
3 | 2 | number22
4 | 2 | number23
So if I do a:
SELECT * FROM Agent LEFT JOIN Econ
I Will Get 4 rows
IdAgent | Name | IdEcon IdAgent Number
1 | Name 1 | 1 | 1 | number1
2 | Name 2 | 2 | 2 | number21
2 | Name 2 | 3 | 2 | number22
2 | Name 2 | 4 | 2 | number23
But if i do a:
SELECT top(2) * FROM Agent LEFT JOIN Econ
I Will Get 2 rows and i want 4 rows (I want the top 2 only to affect the table Agent)
How can I accomplish that?
Untested:
SELECT * FROM (Select top(2) * FROM Agent) LEFT JOIN Econ
You could select the top two agents separately and use the result as a derived table to join to Econ, as in jarlh's answer, or you could use TOP (2) WITH TIES together with ORDER BY Agent.IdAgent:
SELECT TOP (2) WITH TIES
...
FROM
dbo.Agent
LEFT JOIN dbo.Econ ON ...
ORDER BY
Agent.IdAgent ASC
;
Related
I'm trying to build a query where I can select from a table all products with a certain ID but I would also like to find out what products were not found within the IN clause.
Product Table
ID | Name
---|---------
1 | ProductA
2 | ProductB
4 | ProductD
5 | ProductE
6 | ProductF
7 | ProductG
select *
from products
where id in (2,3,7);
As you can see, product id 3 does not exist in the table.
My query will only return rows 2 and 7.
I would like a blank/null row returned if a value in the IN clause did not return anything.
Desired Results:
ID | Name
---|---------
2 | ProductB
3 | null
7 | ProductG
You can use a left join:
select i.id, p.name
from (select 2 as id union all select 3 union all select 7
) i left join
products p
on p.id = i.id
IN is not useful in this case.
Use a CTE with the ids that you want to search for and left join to the table:
with cte(id) as (select * from (values (2),(3),(7)))
select c.id, p.name
from cte c left join products p
on p.id = c.id
See the demo.
Results:
| id | Name |
| --- | -------- |
| 2 | ProductB |
| 3 | |
| 7 | ProductG |
I have two tables, tickets and categories. The categories table has 3 columns of interest: id, name and path. The data looks like this:
id | Name | Path
------------------
1 | ABC | 1
2 | DEF | 1.2
3 | GHI | 1.2.3
4 | JKL | 4
5 | MNO | 4.5
6 | PQR | 4.5.6
9 | STU | 4.5.9
Note that the path column is an l-tree. What this is meant to represent is that the category with id=2 is a subcategory of id=1 and that id=3 is a subcategory of id=2.
In my tickets table, there's a column called category_id which refers to the id column in my categories table. Each ticket can have up to one category assigned to it (category_id may be null).
I'm trying to count all the tickets for each category.
Suppose my tickets table looks like this:
ticket_id | ticket_title | category_id
1 | A | 1
2 | B | 2
3 | C | 3
4 | D | 5
5 | F | 5
6 | G | 6
7 | H | 9
I would like to output:
category_id | count
1 | 3
2 | 2
3 | 1
4 | 4
5 | 4
6 | 1
9 | 1
I've found that I can get all of the tickets which belong to a given category with the following query: select * from tickets where category_id in (select id from categories where path ~ '*.1.*'); (although now that I'm writing this question I'm not convinced this is correct).
I've also attempted to perform the ticket-count-by-category problem and I came up with:
SELECT
categories.id as cid,
COUNT(*) as tickets_count
FROM tickets
LEFT JOIN categories ON tickets.category_id = categories.id
GROUP BY cid;
which outputs the following:
c_id | count
1 | 1
2 | 1
3 | 1
5 | 2
6 | 1
9 | 1
I'm not very good at SQL. Is it possible to achieve what I want?
Try this:
WITH tickets_per_path AS (
SELECT
c.path AS path,
count(*) AS count
FROM tickets t INNER JOIN categories c ON (t.category_id = c.id)
GROUP BY c.path)
SELECT
c.id,
sum(tickets_per_path.count) AS count
FROM categories c LEFT JOIN tickets_per_path ON (c.path #> tickets_per_path.path)
GROUP BY c.id
ORDER BY c.id;
Which yields the following result:
id| count
1 | 3
2 | 2
3 | 1
4 | 4
5 | 4
6 | 1
9 | 1
It roughly works like this:
the WITH clause computes the number of tickets per path (without
including the count of tickets of descendent paths).
the second select clause joins the categories table with the precomputed tickets_per_path view, but instead of an equi-join on path, it
joins by testing whether a record in the left table (categories) is
an ancestor of the right side table (using #> operator). Then it
groups by category id and sums up the ticket counts by category
including the descendant counts.
You are close, but you need a more general join:
SELECT c.id as cid, COUNT(*) as tickets_count
FROM categories c LEFT JOIN
tickets t
ON t.category_id || '.' LIKE c.id || '.%'
GROUP BY c.id;
The '.' in the comparison is just so 1.100 doesn't match 1.1.
I need a query to find duplicate combinations in these tables:
AttributeValue:
id | name
------------------
1 | green
2 | blue
3 | red
4 | 100x200
5 | 150x200
Product:
id | name
----------------
1 | Produkt A
ProductAttribute:
id | id_product | price
--------------------------
1 | 1 | 100
2 | 1 | 200
3 | 1 | 100
4 | 1 | 200
5 | 1 | 100
6 | 1 | 200
7 | 1 | 100 -- duplicate combination
8 | 1 | 100 -- duplicate combination
ProductAttributeCombinations:
id_product_attribute | id_attribute
-------------------------------------
1 | 1
1 | 4
2 | 1
2 | 5
3 | 2
3 | 4
4 | 2
4 | 5
5 | 3
5 | 4
6 | 3
6 | 5
7 | 1
7 | 4
8 | 1
8 | 5
I need SQL that creates result like:
id_product | duplicate_attributes
----------------------------------
1 | {7,8}
If I understand correct, 7 is a duplicate of 1 and 8 is a duplicate of 2. As phrased, your question is a bit confusing, because 7 and 8 are not related to each other and the only table of interest is ProductAttributeCombinations.
If this is the case, then one method is to use string aggregation
with combos as (
select id_product_attribute,
string_agg(id_attribute::text, ',' order by id_attribute) as combo
from ProductAttributeCombinations pac
group by id_product_attribute
)
select *
from combos c
where exists (select 1
from combos c2
where c2.id_product_attribute > c.id_product_attribute and
c2.combo = c.combo
);
Your question leaves some room for interpretation. Here is my educated guess:
For each product, return an array of all instances with the same set of attributes as any other instance of the same product with smaller ID.
WITH combo AS (
SELECT id_product, id, array_agg(id_attribute) AS attributes
FROM (
SELECT pa.id_product, pa.id, pac.id_attribute
FROM ProductAttribute pa
JOIN PoductAttributeCombinations pac ON pac.id_product_attribute = pa.id
ORDER BY pa.id_product, pa.id, pac.id_attribute
) sub
GROUP BY 1, 2
)
SELECT id_product, array_agg(id) AS duplicate_attributes
FROM combo c
WHERE EXISTS (
SELECT 1
FROM combo
WHERE id_product = c.id_product
AND attributes = c.attributes
AND id < c.id
)
GROUP BY 1;
Sorting can be inlined into the aggregate function so we don't need a subquery for the sort (like #Gordon already provided). This is shorter, but also typically slower:
WITH combo AS (
SELECT pa.id_product, pa.id
, array_agg(pac.id_attribute ORDER BY pac.id_attribute) AS attributes
FROM ProductAttribute pa
JOIN PoductAttributeCombinations pac ON pac.id_product_attribute = pa.id
GROUP BY 1, 2
)
SELECT ...
This only returns products with duplicate instances.
SQL Fiddle.
Your table names are rather misleading / contradict the rest of your question. Your sample data is not very clear either, only featuring a single product. I assume there are many in your table.
It's also unclear whether you are using double-quoted table names preserving CaMeL-case spelling. I assume: no.
When using the following query:
with neededSkills(SkillCode) as (
select distinct SkillCode
from job natural join hasprofile natural join requires_skill
where job_code = '1'
minus
select skillcode
from person natural join hasskill
where id = '1'
)
select distinct
taughtin.c_code as c,
count(taughtin.skillcode) as s,
ti.c_code as cc,
count(ti.skillcode) as ss
from taughtin, taughtin ti
where taughtin.c_code <> ti.c_code
and taughtin.skillcode <> ti.skillcode
and taughtin.skillcode in (select skillcode from neededskills)
and ti.skillcode in (select skillcode from neededskills)
group by (taughtin.c_code, ti.c_code)
order by (taughtin.c_code);
It returns:
C | S | CC | SS
----|----|----|----
1 | 1 | 2 | 1
1 | 1 | 3 | 1
1 | 1 | 5 | 1
2 | 1 | 1 | 1
3 | 1 | 1 | 1
5 | 1 | 1 | 1
I would expect it to return only lines where the combination of C and CC was not already used. Do I misunderstand how group by works? How would I achieve this result?
I am trying to have it return:
C | S | CC | SS
----|----|----|----
1 | 1 | 2 | 1
1 | 1 | 3 | 1
1 | 1 | 5 | 1
I use Oracle SQLPlus.
You're grouping on the combination of taughtin.c_code and ti.c_code, which are seperate columns in the context of the query (even though they are the same column in the schema). A pair of 1, 2 is not the same as a pair of 2, 1; the values may be the same but the sources are not.
If you want to get the combinations one way but not the other then the simplest thing is to always make one value large than the other; instead of:
where taughtin.c_code <> ti.c_code
use:
where ti.c_code > taughtin.c_code
Though it would be better to use ANSI joins for the main query too, and I'm not a fan of natural joins. You also don't need either distinct; the first may eliminate duplicates but they don't logically matter if you're only using the temporary result set for in()
I have to make sortable table like this:
Sortable table:
building_id | building_age | title |
-------------------------------------------------
1 | 100 | New york buil |
2 | 50 | House 1 |
3 | 50 | House 10 |
From these tables:
Building Table:
building_id | building_age | building_type_1_FK | building_type_2_FK
---------------------------------------------------------
1 | 100 | null | 1
2 | 50 | 1 | null
3 | 50 | 2 | null
building_type_1:
type_id | title | diff1 |
-------------------------------------------------
1 | New york buil| blablabla |
building_type_2:
building_id | title |
----------------------------
1 | House 1 |
2 | House 10 |
3 | House 500 |
While joining these tables I get several title columns where one of them is not null. Is there any way to sort by title and select top 10 results without fetching all the data and then sorting in the app?
p.s.. I know that in general this architecture is not good, but I can't change it.
Yes. You want to do a left outer join to the two tables, and then bring the results together:
select b.building_id, b.building_age, coalesce(bt1.title, bt2.title) as title
from building b left outer join
building_type_1 bt1
on b.building_type_1_FK = bt1.type_id left outer join
building_type_2 bt2
on b.building_type_2_FK = bt2.building_id;
To get the top 10 results in Oracle:
select *
from (select b.building_id, b.building_age, coalesce(bt1.title, bt2.title) as title
from building b left outer join
building_type_1 bt1
on b.building_type_1_FK = bt1.type_id left outer join
building_type_2 bt2
on b.building_type_2_FK = bt2.building_id
order by title
) b
where rownum <= 10;