How to search using a delimited string as array in query - sql

I am trying to search for records columns that match a value within a delimited string.
I have two tables that look like this
Vehicles
| Id | Make | Model |
|----|------|-------|
| 1 | Ford | Focus |
| 2 | Ford | GT |
| 3 | Ford | Kuga |
| 4 | Audi | R8 |
Monitor
| Id | Makes | Models |
|----|-------|----------|
| 1 | Ford | GT,Focus |
| 2 | Audi | R8 |
What I'm trying to achieve is the following:
| Id | Makes | Models | Matched_Count |
|----|-------|----------|---------------|
| 2 | Audi | R8 | 1 |
| 1 | Ford | GT,Focus | 2 |
Using the following query I can get matches on singular strings, but I'm not sure how I can split the commas to search for individual models.
select Id, Makes, Models, (select count(id) from Vehicles va where UPPER(sa.Makes) = UPPER(va.Make) AND UPPER(sa.Models) = UPPER(va.Model)) as Matched_Count
from Monitor sa
(I am using a very SQL Server 2016 however I do not have access to create custom functions or variables)

If you are stuck with this data model, you can use string_split():
select m.*, v.matched_count
from monitor m outer apply
(select count(*) as matched_count
from string_split(m.models, ',') s join
vehicles v
on s.value = v.model and m.makes = v.makes
) v;
I would advise you to put your efforts into fixing the data model, though.
Here is a db<>fiddle.

Related

How to select table with a concatenated column?

I have the following data:
select * from art_skills_table;
+----+------+---------------------------+
| ID | Name | skills |
+----+------+---------------------------|
| 1 | Anna | ["painting","photography"]|
| 2 | Bob | ["drawing","sculpting"] |
| 3 | Cat | ["pastel"] |
+----+------+---------------------------+
select * from computer_table;
+------+------+-------------------------+
| ID | Name | skills |
+------+------+-------------------------+
| 1 | Anna | ["word","typing"] |
| 2 | Cat | ["code","editing"] |
| 3 | Bob | ["excel","code"] |
+------+------+-------------------------+
I would like to write an SQL statement which results in the following table.
+------+------+-----------------------------------------------+
| ID | Name | skills |
+------+------+-----------------------------------------------+
| 1 | Anna | ["painting","photography","word","typing"] |
| 2 | Bob | ["drawing","sculpting","excel","code"] |
| 3 | Cat | ["pastel","code","editing"] |
+------+------+-----------------------------------------------+
I've tried something like SELECT * from art_skills_table LEFT JOIN computer_table ON name. However it doesn't give what I need. I've read about array_cat but I'm having a bit of trouble implementing it.
if the skills column from both tables are arrays, then you should be able to get away with this:
SELECT a.ID, a.name, array_cat(a.skills, c.skills)
FROM art_skills_table a LEFT JOIN computer_table c
ON c.id = a.id
That said, While you used LEFT join in your sample, I think either an INNER or FULL (OUTER) join might serve you better.
First, i wondered why the data are stored in such a model.
Was of the opinion that NoSQL databases lack ability for joins and ...
... a semantic triple would be in the form of subject–predicate–object.
... a Key-value (KV) stores use associative arrays.
... a relational database would be normalized.
A few information about the use case would have helped.
Nevertheless, you can select the data with CONCAT and REPLACE for the desired form.
SELECT art_skills_table.ID, computer_table.name,
CONCAT(
REPLACE(art_skills_table.skills, '}',','),
REPLACE(computer_table.skills, '{','')
)
FROM art_skills_table JOIN computer_table ON art_skills_table.ID = computer_table.ID
The query returns the following result:
+----+------+--------------------------------------------+
| ID | Name | Skills |
+----+------+--------------------------------------------+
| 1 | Anna | {"painting","photography","word","typing"} |
| 2 | Cat | {"drawing","sculpting","code","editing"} |
| 3 | Bob | {"pastel","excel","code"} |
+----+------+--------------------------------------------+
I've used the ID for the JOIN, even though Bob has different values.
The JOIN should probably be done over the name.
JOIN computer_table ON art_skills_table.Name = computer_table.Name
BTW, you need to tell us what SQL engine you're running on.

When Querying Many-To-Many Relationship in SQL, Return Multiple Connections As an Array In Single Row?

Basically, I have 3 tables, titles, providers, and provider_titles.
Let's say they look like this:
| title_id | title_name |
|------------|----------------|
| 1 | San Andres |
| 2 |Human Centipede |
| 3 | Zoolander 2 |
| 4 | Hot Pursuit |
| provider_id| provider_name |
|------------|----------------|
| 1 | Hulu |
| 2 | Netflix |
| 3 | Amazon_Prime |
| 4 | HBO_GO |
| provider_id| title_id |
|------------|----------------|
| 1 | 1 |
| 1 | 2 |
| 2 | 1 |
| 3 | 1 |
| 3 | 3 |
| 4 | 4 |
So, clearly there are titles with multiple providers, yeah? Typical many-to-many so far.
So what I'm doing to query it is with a JOIN like the following:
SELECT * FROM provider_title JOIN provider ON provider_title.provider_id = provider.provider_id JOIN title ON title.title_id = provider_title.title_id WHERE provider.name IN ('Netflix', 'HBO_GO', 'Hulu', 'Amazon_Prime')
Ok, now to the actual issue. I don't want repeated title names back, but I do want all of the providers associated with the title. Let me explain with another table. Here is what I am getting back with the current query, as is:
| provider_id| provider_name | title_id | title_name |
|------------|---------------|----------|---------------|
| 1 | Hulu | 1|San Andreas |
| 1 | Hulu | 2|Human Centipede|
| 2 | Netflix | 1|San Andreas |
| 3 | Amazon_Prime | 1|San Andreas |
| 3 | Amazon_prime | 3|Zoolander 2 |
| 4 | HBO_GO | 4|Hot Pursuit |
But what I really want would be something more like
| provider_id| provider_name |title_id| title_name|
|------------|-----------------------------|--------|-----------|
| [1, 2, 3] |[Hulu, Netflix, Amazon_Prime]| 1|San Andreas|
Meaning I only want distinct titles back, but I still want each title's associated providers. Is this only possible to do post-sql query with logic iterating through the returned rows?
Depending on your database engine, there may be an aggregation function to help achieve this.
For example, this SQLfiddle demonstrates the postgres array_agg function:
SELECT t.title_id,
t.title_name,
array_agg( p.provider_id ),
array_agg( p.provider_name )
FROM provider_title as pt
JOIN
provider as p
ON pt.provider_id = p.provider_id
JOIN title as t
ON t.title_id = pt.title_id
GROUP BY t.title_id,
t.title_name
Other database engines have equivalents. For example:
mySQL has group_concat
Oracle has listagg
sqlite has group_concat (as well!)
If your database isn't covered by the above, you can google '[Your database engine] aggregate comma delimited string'

SQL query for many-to-many self-join

I have a database table that has a companion many-to-many self-join table alongside it. The primary table is part and the other table is alternate_part (basically, alternate parts are identical to their main part with different #s). Every record in the alternate_part table is also in the part table. To illustrate:
`part`
| part_id | part_number | description |
|---------|-------------|-------------|
| 1 | 00001 | wheel |
| 2 | 00002 | tire |
| 3 | 00003 | window |
| 4 | 00004 | seat |
| 5 | 00005 | wheel |
| 6 | 00006 | tire |
| 7 | 00007 | window |
| 8 | 00008 | seat |
| 9 | 00009 | wheel |
| 10 | 00010 | tire |
| 11 | 00011 | window |
| 12 | 00012 | seat |
`alternate_part`
| main_part_id | alt_part_id |
|--------------|-------------|
| 1 | 5 | // Wheel
| 5 | 1 | // |
| 5 | 9 | // |
| 9 | 5 | // |
| 2 | 6 | // Tire
| 6 | 2 | // |
| ... | ... | // |
I am trying to produce a simple SQL query that will give me a list of all alternates for a main part. The tricky part is: some alternates are only listed as alternates of alternates, it is not guaranteed that every viable alternate for a part is listed as a direct alternate. e.g., if 'Part 3' is an alternate of 'Part 2' which is an alternate of 'Part 1', then Part 3 is an alternate of Part 1 (even if the alternate_part table doesn't list a direct link). The reverse is also true (Part 1 is an alternate of Part 3).
Basically, right now I'm pulling alternates and iterating through them
SELECT p.*, ap.*
FROM part p
INNER JOIN alternate_part ap ON p.part_id = ap.main_part_id
And then going back and doing the same again on those alternates. But, I think there's got to be a better way.
The SQL query I'm looking for will basically give me:
| part_id | alt_part_id |
|---------|-------------|
| 1 | 5 |
| 1 | 9 |
For part_id = 1, even when 1 & 9 are not explicitly linked in the alternates table.
Note: I have no control whatever over the structure of the DB, it is a distributed software solution.
Note 2: It is an Oracle platform, if that affects syntax.
You have to create hierarchical tree , probably you have to use connect by prior , nocycle query
something like this
select distinct p.part_id,p.part_number,p.description,c.main_part_id
from part p
left join (
select main_part_id,connect_by_root(main_part_id) real_part_id
from alternate_part
connect by NOCYCLE prior main_part_id = alternate_part_id
) c
on p.part_id = c.real_part_id and p.part_id != c.main_part_id
order by p.part_id
You can read full documentation about Hierarchical queries at http://docs.oracle.com/cd/B28359_01/server.111/b28286/queries003.htm

PostgreSQL Inner Join on the same table + second table?

If this is a stupid question, forgive me, I'm not very familiar with PostgreSQL.
I've collected inventory data from used car dealerships in my area and stored it in a postgreSQL table. I've got a second table with particular details regarding certain makes and models. For example:
The dealership table is structured like so:
-----------------------------------------
| Dealership | Make | Model | Year | ID |
----------------------------------------|
| A | Ford | F250 | 2003 | 1 |
| A | Chevy| Cobalt| 2005 | 2 |
| B | Ford | F250 | 2003 | 1 |
| B | Dodge| Chrgr | 2012 | 3 |
-----------------------------------------
The details table is structured like so:
-----------------------------------------
| ID | DetailA| DetailB| DetailC|
-----------------------------------------
| 1 | data | data | data |
| 2 | data | data | data |
| 3 | data | data | data |
| 4 | data | data | data |
-----------------------------------------
My goal is to retrieve vehicle matches from multiple dealerships and display the appropriate details. In the above example, I would like to see:
-----------------------------------------------------
| Make | Model | Year | DetailA | DetailB | DetailC |
-----------------------------------------------------
| Ford | F250 | 2003 | data | data | data |
-----------------------------------------------------
With this result, I will know that both A and B havea 2003 Ford F250 for sale, and can view the related details of the vehicle.
I've tried many different queries, but most are variations on something like this:
SELECT DISTINCT
dealership_table.make,
dealership_table.model,
dealership_table.year
details_table.detaila,
details_table.detailb,
details_table.detailc
FROM
dealership_table
INNER JOIN
details_table
ON
dealership_table.id = details_table.id
WHERE
dealership_table.dealership = 'A'
OR
dealership_table.dealership = 'B'
However this returns all of the distinct matches from the table where dealership is either A or B. I've tried multiple inner-joins, but I an error complaining details_table is specified multiple times.
If I'm doing something really silly, I apologize. Like I said before, I'm pretty much an SQL noob.
What am I doing wrong? How should I go about retrieving the desired results? Any suggestions, solutions, or advice is greatly appreciated!
You can write:
SELECT dealership_table1.make,
dealership_table1.model,
dealership_table1.year,
details_table.detaila,
details_table.detailb,
details_table.detailc
FROM dealership_table dealership_table1
JOIN dealership_table dealership_table2
ON dealership_table1.make = dealership_table2.make
AND dealership_table1.model = dealership_table2.model
AND dealership_table1.year = dealership_table2.year
JOIN details_table
ON dealership_table.id = details_table.id
WHERE dealership_table1.dealership = 'A'
AND dealership_table1.dealership = 'B'
;
(Note that the FROM dealership_table dealership_table1 and JOIN dealership_table dealership_table2 set up distinct "aliases", so you can use the same table multiple different times in the same query without getting name-conflicts.)
I may be misunderstanding your table layout, but I think you should consider changing to a different structure. Here's what I would propose:
Vehicle:
----------------------------
| ID | Make | Model | Year |
----------------------------
| 1 | Ford | F250 | 2003 |
| 2 | Chevy| Cobalt| 2005 |
| 3 | Dodge| Chrgr | 2012 |
----------------------------
Dealership:
----------------------------
| Dealership | ID | Detail |
----------------------------
| A | 1 | data |
| A | 2 | data |
| B | 1 | data |
| B | 3 | data |
----------------------------
This way you're not storing vehicle information (make/model/year) in more than one place.
Here's how you would write your desired query given the above schema:
SELECT Make, Model, Year, A.Detail, B.Detail, C.Detail
FROM Vehicle V
LEFT OUTER JOIN Dealership A on A.Dealership = 'A' and A.id = V.id
LEFT OUTER JOIN Dealership B on B.Dealership = 'B' and B.id = V.id
LEFT OUTER JOIN Dealership C on C.Dealership = 'C' and C.id = V.id

Grouped string aggregation / LISTAGG for SQL Server

I'm sure this has been asked but I can't quite find the right search terms.
Given a schema like this:
| CarMakeID | CarMake
------------------------
| 1 | SuperCars
| 2 | MehCars
| CarMakeID | CarModelID | CarModel
-----------------------------------------
| 1 | 1 | Zoom
| 2 | 1 | Wow
| 3 | 1 | Awesome
| 4 | 2 | Mediocrity
| 5 | 2 | YoureSettling
I want to produce a dataset like this:
| CarMakeID | CarMake | CarModels
---------------------------------------------
| 1 | SuperCars | Zoom, Wow, Awesome
| 2 | MehCars | Mediocrity, YoureSettling
What do I do in place of 'AGG' for strings in SQL Server in the following style query?
SELECT *,
(SELECT AGG(CarModel)
FROM CarModels model
WHERE model.CarMakeID = make.CarMakeID
GROUP BY make.CarMakeID) as CarMakes
FROM CarMakes make
http://www.simple-talk.com/sql/t-sql-programming/concatenating-row-values-in-transact-sql/
It is an interesting problem in Transact SQL, for which there are a number of solutions and considerable debate. How do you go about producing a summary result in which a distinguishing column from each row in each particular category is listed in a 'aggregate' column? A simple, and intuitive way of displaying data is surprisingly difficult to achieve. Anith Sen gives a summary of different ways, and offers words of caution over the one you choose...
If it is SQL Server 2017 or SQL Server VNext, Azure SQL database you can use String_agg as below:
SELECT make.CarMakeId, make.CarMake,
CarModels = string_agg(model.CarModel, ', ')
FROM CarModels model
INNER JOIN CarMakes make
ON model.CarMakeId = make.CarMakeId
GROUP BY make.CarMakeId, make.CarMake
Output:
+-----------+-----------+---------------------------+
| CarMakeId | CarMake | CarModels |
+-----------+-----------+---------------------------+
| 1 | SuperCars | Zoom, Wow, Awesome |
| 2 | MehCars | Mediocrity, YoureSettling |
+-----------+-----------+---------------------------+