I have a list of categories that are saved in a string. One is on an article table the other on an ad table. I need the script to return all rows that have a combination of any of these categories between the two tables.
Category string on both tables:
Civic,Community,Sports,Business
And my MySQL script
SELECT `Ad_ID`, `Ad_URL`, `Ad_Image`, `Ad_Type`, `Ad_Cities`, `Ad_Categories`
FROM `Ad_TABLE`
INNER JOIN `Article_TABLE` ON `Article_TABLE`.`Article_Cat` = `Ad_TABLE`.`Ad_Cat`
WHERE Article_TABLE.Article_Cat LIKE '%Civic%'
OR Article_TABLE.Article_Cat LIKE '%Community%'
OR Article_TABLE.Article_Cat LIKE '%Sports%'
OR Article_TABLE.Article_Cat LIKE '%Business%'
AND Ad_TABLE.Ad_Cat LIKE '%Civic%'
OR Ad_TABLE.Ad_Cat LIKE '%Community%'
OR Ad_TABLE.Ad_Cat LIKE '%Sports%'
OR Ad_TABLE.Ad_Cat LIKE '%Business%'
The script only returns records that are only in one of these categories, but there are records that are in multiple categories and I need it to return those as well.
How can I get it to where it finds all matching categories between the two tables?
I suspect you need to add parenthesis to the WHERE clause:
SELECT `Ad_ID`, `Ad_URL`, `Ad_Image`, `Ad_Type`, `Ad_Cities`, `Ad_Categories`
FROM `Ad_DB`
INNER JOIN `Article_DB` ON `Article_DB`.`Article_Cat` = `Ad_DB`.`Ad_Cat`
WHERE (Article_DB.Article_Cat LIKE '%Civic%'
OR Article_DB.Article_Cat LIKE '%Community%'
OR Article_DB.Article_Cat LIKE '%Sports%'
OR Article_DB.Article_Cat LIKE '%Business%')
AND (Ad.DB_Cat LIKE '%Civic%'
OR Ad.DB_Cat LIKE '%Community%'
OR Ad.DB_Cat LIKE '%Sports%'
OR Ad.DB_Cat LIKE '%Business%')
I'm not sure exactly how your tables are structured, but this query will return rows where Article_DB.Article_Cat AND Ad.DB_Cat contain one of your categories. You likely want to rethink the way you store data in these tables so that you're not duplicating data.
Here's a guess. This is just a guess, based on a possible interpretation of the nebulous specification.
To "match" rows that have one or more of these four categories in common
Civic,Community,Sports,Business
We could use a query with join predicates like this:
SELECT ...
FROM `Ad_DB` d
JOIN `Article_DB` r
ON ( FIND_IN_SET('Civic' ,d.ad_categories)
AND FIND_IN_SET('Civic' ,r.article_cat )
)
OR ( FIND_IN_SET('Community' ,d.ad_categories)
AND FIND_IN_SET('Community' ,r.article_cat )
)
OR ( FIND_IN_SET('Sports' ,d.ad_categories)
AND FIND_IN_SET('Sports' ,r.article_cat )
)
OR ( FIND_IN_SET('Business' ,d.ad_categories)
AND FIND_IN_SET('Business' ,r.article_cat )
)
ORDER BY ...
NOTE: I understand that we get what we get, and sometimes we get handed a database that stores comma separated lists.
Storing comma separated lists in a column is a SQL Antipattern. For anyone that has an interest as to why it's an antipattern, I recommend Chapter 2 of Bill Karwin's excellent book
https://www.amazon.com/SQL-Antipatterns-Programming-Pragmatic-Programmers/dp/1934356557
Related
I tried to make a query to my database with this structure: Data Base Structure
I did this query:
SELECT partido.acronimoPartido, SUM(votosacta.numVotos) FROM partido, votosacta WHERE votosacta.partido_idpartido=1 AND partido.idpartido=1
This query does work like I want but displays only the SUM of 'votos' for idpartido=1
I want to be able to sum numVotos from 'votosacta' table for each member of my 'partido' table indexed in 'votosacta' but I seem to not be able to get the right sintax.
I tried something like this:
SELECT partido.acronimoPartido, SUM(votosacta.numVotos) FROM partido, votosacta WHERE votosacta.partido_idpartido = partido.idpartido
You need a group by clause:
select p.acronimoPartido,
SUM(v.numVotos)
from partido p
join votosacta v on v.partido_idpartido = p.idpartido
group by p.acronimoPartido
Also, use explicit join syntax instead of old comma based syntax and use aliases to make your queries concise and readable.
I've (on reflection ridiculously) stored our 'punters' in 2 tables depending on whether they registered or paid through the express checkout form.
My SQL looks like this:
SELECT
DISTINCT(sale_id), sale_punter_type, sale_comment, sale_refund, sale_timestamp,
punter_surname, punter_firstname,
punter_checkout_surname, punter_checkout_firstname,
punter_compo_surname, punter_compo_firstname,
sale_random, sale_scanned, sale_id
FROM
sale
LEFT JOIN
punter ON punter_id = sale_punter_no
LEFT JOIN
punter_checkout ON punter_checkout_id = sale_punter_no
LEFT JOIN
punter_compo ON punter_compo_id = sale_punter_no
WHERE
sale_event_no = :id
ORDER BY
punter_surname, punter_firstname,
punter_checkout_surname, punter_checkout_firstname
It returns results BUT lists the registered users alphabetically first, then the checkout punters alphabetically.
My question is there a way to get all of the users (registered or checkout) all together sorted alphabetically in 1 sorted list instead of 2 joined sorted lists.
I thought maybe I could use something like punter_checkout_surname AS punter_surname but that didn't work.
Any thoughts? I know now that I shouldn't have used 2 separate tables but but I'm stuck with it now.
Thank you.
I think you just want to use coalesce().
ORDER BY COALESCE(punter_surname, punter_checkout_surname)
COALESCE(punter_firstname, punter_checkout_firstname)
Other comments:
I doubt that DISTINCT is necessary. Why would this generate multiple rows for a single sale_id?
When a query has multiple tables, qualify all the column names (that is, include table aliases so you and others know where the table comes from).
Your data has three sets of names. That seems overkill.
You might want to put the COALESCE() in the SELECT so you don't have quite so many names generated by the query.
Here's my answer:
ORDER BY
COALESCE( UCASE( punter_surname) , UCASE( punter_checkout_surname ), UCASE( punter_compo_surname ) ) ,
COALESCE( UCASE( punter_firstname ) , UCASE( punter_checkout_firstname ), UCASE( punter_compo_firstname) )
In the usual Customer with Orders example, this kind of SQLAlchemy code...
data = db.query(Customer)\
.join(Order, Customer.id == Order.cst_id)\
.filter(Order.amount>1000)
...would provide instances of the Customer model that are associated with e.g. large orders (amount > 1000). The resulting Customer instances would also include a list of their orders, since in this example we used backref for that reason:
class Order:
...
customer = relationship("customers", backref=backref('orders'))
The problem with this, is that iterating over Customer.orders means that the DB will return complete instances of Order - basically doing a 'select *' on all the columns of Order.
What if, for performance reasons, one wants to e.g. read only 1 field from Order (e.g. the id) and have the .orders field inside Customer instances be a simple list of IDs?
customers = db.query(Customer)....
...
pdb> print customers[0].orders
[2,4,7]
Is that possible with SQLAlchemy?
What you could do is make a query this way:
(
session.query(Customer.id, Order.id)
.select_from(Customer)
.join(Customer.order)
.filter(Order.amount > 1000)
)
It doesn't produce the exact result as what you have asked, but it gives you a list of tuples which looks like [(customer_id, order_id), ...].
I am not entirely sure if you can eagerly load order_ids into Customer object, but I think it should, you might want to look at joinedload, subqueryload and perhaps go through the relationship-loading docs if that helps.
In this case it works you could write it as;
(
session.query(Customer)
.select_from(Customer)
.join(Customer.order)
.options(db.joinedload(Customer.orders))
.filter(Order.amount > 1000)
)
and also use noload to avoid loading other columns.
I ended up doing this optimally - with array aggregation:
data = db.query(Customer).with_entities(
Customer,
func.ARRAY_AGG(
Order.id,
type_=ARRAY(Integer, as_tuple=True)).label('order_ids')
).outerjoin(
Orders, Customer.id == Order.cst_id
).group_by(
Customer.id
)
This returns tuples of (CustomerEntity, list) - which is exactly what I wanted.
A web site I support executes a MySQL database query that looks like this:
SELECT
person_per.per_ID
FROM
person_per
LEFT JOIN
person_custom
ON
person_custom.per_ID=person_per.per_ID
where
(per_City='Cathedral City') or
(per_City='Cherry Valley') or
(per_City='Coachella') or
[...and so on for several dozen cities...];
The query is supposed to return the set of people who live in any of the specified list of cities. The query is ugly and verbose, but it works fine.
However, the new request is to modify the query so that it checks not only the person_per.per_City field but also the person_custom.work_City field as well, so that the query returns any one who either lives or works in any of the specified cities.
The naive way to do this would be to simply double the number of "or" clauses, like this:
SELECT
person_per.per_ID
FROM
person_per
LEFT JOIN
person_custom
ON
person_custom.per_ID=person_per.per_ID
where
(per_City='Cathedral City') or
(work_City='Cathedral City') or
(per_City='Coachella') or
(work_City='Coachella') or
[...and so on for several dozen cities...];
But I'd like to avoid doing it that way if possible, because the only thing worse then a 20-line SQL query containing the entire list of city-names is a 40-line SQL query containing the entire list of city-names twice. That query would be (even more) difficult to write and maintain.
So, is there a way to phrase this query-on-two-columns such that each city's name only appears once in the query? (I know I could create an SQL table of city names, but I'd rather not modify the applications' set of SQL tables if possible, so I'd prefer a solution that modifies only the SQL query itself)
You should use the IN operator to check if a value is in a list of other values, so the first query would be simplified to:
SELECT person_per.per_ID
FROM person_per
LEFT JOIN person_custom USING(per_ID)
WHERE per_City IN ( 'Cathedral City', 'Cherry Valley', 'Coachella', ... )
For the second query I would recommend either storing the list of cities in a table or a variable to reduce duplication. The table version of the query would look something like:
SELECT person_per.per_ID
FROM person_per
LEFT JOIN person_custom USING(per_ID)
WHERE per_City IN ( SELECT cities_City FROM cities )
OR work_City IN ( SELECT cities_City FROM cities )
As mentioned in the comments, use the "in" operator:
SELECT
person_per.per_ID
FROM
person_per
LEFT JOIN
person_custom
ON
person_custom.per_ID=person_per.per_ID
where
per_City in ('Cathedral City','Coachella', 'city1', 'city2', ...) OR
work_City in ('Cathedral City','Coachella', 'city1', 'city2', ...)
Comma seperated strings could be easily build up with every programing language, so you shouldn't have to much work on this.
I got the following sql question that I that won´t work for me. I know that the last CASE row are wrong but I would like to use a CASE statement like that in my where clause.
Short description of my situation:
I got several companies that got there own material linked to them with "companyID". Each material might be linked to a row in pricelist_entries. If I search for one row in the pricelist_entries table that is linked to many material rows all rows will be returned but I just want to return the one that belongs to the current company (the company that performs the search).
Conclusion: If materialID NOT NULL THEN materials.company="current.companyID".
SELECT peID, peName, materialID
FROM pricelist_entries
INNER JOIN pricelist ON pricelist_entries.peParentID=pricelist.pID
LEFT JOIN materials ON pricelist_entries.peID=materials.pricelist_entries_id
WHERE peBrand = 'Kama' AND pricelist.pCurrent = 1
AND (peName LIKE '%gocamp de%' OR peArtnr LIKE '%gocamp de%')
AND pricelist.country=0 AND pricelist_entries.peDeleted=0
CASE materialID WHEN IS NOT NULL THEN materials.companyID=10 END
Please tell me if I need to describe my problem in a better way.
Thanks in advance!
Sounds like just moving the condition into the join would make it simpler;
SELECT peID, peName, materialID
FROM pricelist_entries
INNER JOIN pricelist
ON pricelist_entries.peParentID=pricelist.pID
LEFT JOIN materials
ON pricelist_entries.peID=materials.pricelist_entries_id
AND materials.companyID=10 -- << condition
WHERE peBrand = 'Kama' AND pricelist.pCurrent = 1
AND (peName LIKE '%gocamp de%' OR peArtnr LIKE '%gocamp de%')
AND pricelist.country=0 AND pricelist_entries.peDeleted=0
It will only left join in material rows that are linked to the correct company.
You can't use CASE in the where clause that I'm aware of, you need to use it in the SELECT portion, but it will have the same effect. Something like this should work:
SELECT CASE materialid WHEN IS NOT NULL THEN companyid END as thiscompanyid
This will give you a new column named thiscompanyid and you can query off of that to get what you need.