I have a campaign node which has a relationship with Picture node.
I'm trying to get , in each campaign that the query finds , a random picture which connected to it.
I managed to get a random picture to a single campaign, but if I want to each campaign a connected picture output, I'm having trouble to do it.
This is an example to get a single picture to within a campaign.
MATCH (campaign:Campaign)-[]-(picture:Picture) where
campaign.id="1429184083571" or campaign.id='1429182615443'
WITH picture, rand() AS r,campaign
ORDER BY r
RETURN campaign,picture
limit 1
How can i get an output for each campaign a connected random picture ?
This should work:
MATCH (campaign:Campaign)-[]-(picture:Picture)
with campaign, collect(picture) as pictures
RETURN campaign,pictures[toInt(rand()*size(pictures))]
Related
I'm a newbie when it comes to Google Doc Filters and I would appreciate some help.
I got a list with articles where I would like to filter by company (in this case SONY), but also filtering by lowest price combined with lowest shipping costs.
Example: the first filter I created, creates a list with SONY articles.
=(filter(A2:D12;A2:A12="SONY"))
Now I would like the filter to give out a single row, where the price and the shipping costs are the lowest, in this case, the product is:
SONY headphones with the price of 20 and shipping costs of 2,99
Im basically trying to combine the filters:
=(filter(A2:D12;A2:A12="SONY"))
=SMALL((C2:C12);2)
=SMALL((D2:D12);2)
in one single, long filter
Thank you
SEE SCREENSHOT HERE
Solution:
FILTER would not work in your case because you have a priority column to be filtered, in this case, column A before C and D.
You may use QUERY instead:
=QUERY(A2:D12,"select * where A='A' order by C+D limit 1")
This would select the entry with a specified value in column A (company), then order by the sum of C and D (price+shipping) in ascending order, and then output the first row, which is the minimum.
Sample Sheet:
References:
QUERY function
QUERY language
I'm trying to extract information from Wikipedia tables.
More specifically, I'm trying to make a list of all teams and all players in the premier league.
Until now I'm able to traverse over the whole teams in the premier league 2019-2020 table of teams, for every team there I get in it Wikipedia page and traverse over its player's getting their information.
I thought there is a fixed template that all premier league teams in Wikipedia have their table of players at position 3 but after traversing 6 teams it faced a team that it's table is in 2nd place.
So I was using the following XPath query on every team wiki page
"//table[3]/tbody//tr[position() > 1]//td[4]//span/a/#href"
but for example, the following team players table is at position 2, how can I make this query more generic and not fix it a certain position? I have noticed that all of my relevant tables have an element before it with the text "First-team squad"
The HTML of the table is too long, so I post here the wiki link of a certain team
https://en.wikipedia.org/wiki/Crystal_Palace_F.C.
Hope to get help! thanks.
You have to use another "anchor" which works for each page. The table you need is always the first after the span element "Players".
So with this :
//span[#id='Players']/following::table[1]//span[#class="fn"]//text()
You'll get the names of all players of the current squad team.
With this :
//span[#id='Players']/following::table[1]//span[#class="fn"]//#href
You'll get the associated URLs. /!\ Some players don't have a wikipedia webpage.
So you can have 26 player names but 25 urls. Like here :
https://en.wikipedia.org/wiki/Chelsea_F.C.
I'm writing a custom search function, and I have to filter through an association.
I have 2 active record backed models, cards and colors with a has_many_and_belongs_to, and colors have an attribute color_name
As my DB has grown to around 10k cards, my search function gets exceptionally slow because i have a select statement with a query inside it, so essentially im having to make thousands of queries.
i need to convert the array#select method into an active record query, that will yield the same results, and im having trouble coming up with a solution. the current (relevant code) is the following:
colors = [['Black'], ['Blue', 'Black']] #this is a parameter retrieved from a form submission
if color
cards = color.flat_map do |col|
col.inject( Card.includes(:colors) ) do |memo, color|
temp = cards.joins(:colors).where(colors: {color_name: color})
memo + temp.select{|card| card.colors.pluck(:color_name).sort == col.sort}
end
end
end
the functionality im trying to mimic is that only cards with colors exactly matching the incoming array will be selected by the search (comparing two arrays). Because cards can be mono-red, red-blue, or red-blue-green etc, i need to be able to search for only red-blue cards or only mono-red cards
I initially started along this route, but i'm having trouble comparing arrays with an active record query
color_objects = Color.where(color_name: col)
Card.includes(:colors).where('colors = ?', color_objects)
returns the error
ActiveRecord::StatementInvalid: PG::SyntaxError: ERROR: syntax error
at or near "SELECT" LINE 1: ...id" WHERE "cards"."id" IN (2, 3, 4) AND
(colors = SELECT "co...
it looks to me like its failing because it doesnt want to compare arrays, only table elements. is this functionality even possible?
One solution might be to convert the habtm into has many through relation and make join tables which contain keys for every permutation of colors in order to access those directly
I need to be able to search for only green-black cards, and not have mono-green, or green-black-red cards show up.
I've deleted my previos answer, because i did not realized you are looking for the exact match.
I played a little with it and i can't see any solution without using an aggregate function.
For Postgres it will be array_agg.
You need to generate an SQL Query like:
SELECT *, array_to_string(array_agg(colors.color_name), ',')) as color_names FROM cards
JOINS cards_colors, colors
ON (cards.id = cards_colors.card_id AND colors.id = cards_colors.color_id)
GROUP BY cards.id HAVING color_names = 'green, black'
I never used those aggregators, so perhaps array_to_string is a wrong formatter, anyway you have to watch for aggregating the colors in alphabetical order. As long as you aint't having too many cards it will be slow enough, but it will scan every card in a table.
I you want to use an index on this query, you should denormalize your data structure, use an array of color_names on a cards record, index that array field and search on it. You can also keep you normalized structure and define an automatic association callback which will put the colorname to the card's color_names array every time a color is assigned to a card.
try this
colors = Color.where(color_name: col).pluck(:id)
Card.includes(:colors).where('colors.id'=> colors)
My app has a class that saves picture that users upload. Each object in the class has a city property that holds the name of the city that the picture was taken at, and a like property that tracks the number of likes.
I want to be able to send a query that returns one picture per city and each picture should have the highest ranking of likes in the city it belongs to. How can I do that?
One way which I first thought about is doing multiple queries by fetching the most liked picture of a city and save it in an array, and then do the same to other cities.
However, each country has more than one city, thus it's not that efficient.
Parse doesn't support the ordinary operations used in databases. Besides, I tried to use a compound query. Unfortunately, I can't set limit or ordering on the subqueries. Any good solution for this?
It would be easy using group by. Unfortunately, Parse does not support "select distinct" or "group by" features.
As you've suggested you need to fetch for each country all the cities, and for each one get the top most rated photo.
BUT, since Parse has strict restrictions on the duration time execution of a request ( 3 sec for an event listener, 7 sec for a custom function ), I suggest you to do this in a background job, saving in a new table the top rated photo for each city. In this way you can easily query the db from client. The Background jobs can be executed up to 15 minuted before parse drop them, so you could make that kind of queries without timeouts.
Hope it helps
I have an app that (among other things) uses Yahoo Weather API to display weather conditions for a location selected by user.
In the configuration dialog where user can enter the location, I'd love to offer autocompletion so that while user is typing location name, list of matching cities is suggested.
I can use YQL to fetch locations matching the prefix, i.e.:
select * from geo.places where text = 'Vie*'
but the problem is that not every location has a weather station associated with it and I'd love to skip these in my autocompletion list.
Using community tables (table called weather.woeid), following query will join previous query with the weather api, returning only locations that do have weather stations:
select location from weather.woeid where w in (select woeid from geo.places where text = 'Vie*')
This almost solves my problem, except for the fact that previous query (which produces same result as weather api call) doesn't return WOEID nor any kind of identifier I can use to directly query the Weather API after configuration. How can I capture the value of join parameter w? I tried something like select w, location ... but that doesn't seem to work.
Is there any other way to get list of locations (incl. WOEID) matching certain prefix that have weather data associated with them?
Afaik it is not possible with YQL to pass through values from the Sub-Select (the inner SELECT statement) to the outer SELECT, which I is what you want to do if I understand you correctly.
Based on your use case I want to propose another solution though:
I assume that the list of locations that have a weather station associated with them is relatively static, meaning this list does not change very often. If that is the case then it would not be very optimal in terms of performance to regenerate that list every time with YQL. Instead I would generate that list offline, store it in a file or MySQL or elsewhere and then just use that static list to answer to the AJAX call of your autocomplete field.
The data in that static list could look something like this:
{
"Vienna" => 72342,
"Hamburg" => 12334,
...
}
Once the user has selected a location and pressed enter, then you can send the YQL query to weather.woeid to look up the current weather based on the WOEID.