I'm using Postgres for my db, and I have a column in my Auction model as a jsonb column. I want to create a query that searches the Auction's json column to see whether a user's name OR email exists in any Auction instance's json column.
Right now I have #auctions = Auction.where('invitees #> ?', {current_user.name.downcase => current_user.email.downcase}.to_json), but that only brings back exact key => value matches I want to know whether the name OR the email exists.
You're using the #> operator. The description for it is this:
“Does the left JSON value contain the right JSON path/value entries
at the top level?”
You probably want the ? operator if you want to return a row when the key (name in your case) matches.
There's not a good way to search for values only in a JSON column (see this answer for more details), but you could check if the key exists alone or the key and value match exists.
The same ActiveRecord methods and chaining apply as when using non-JSON columns, namely where and where(…).or(where(…)):
class Auction
def self.by_invitee(user)
name = user.name.downcase
json = { name => user.email } # note: you should be downcasing emails anyways
where('invitee ? :name', name: name).or(
where('invitee #> :json', json: json)
)
end
end
This is just a temporary patch until I add an Invite model, but casting the invitee column to text I can search the columns. Like so
SELECT * FROM auctions
WHERE data::text LIKE "%#{string I'm searching for}%"
So, AR:
Auction.where('data::text LIKE ?', "%#{string I'm searching for}%")
Related
I have a PostgreSQL table called files which includes a jsonb table called formats. While some rows are [null], others have objects with this structure:
{
"thumbnail": {
"ext": ".jpg",
"url": "https://some-url.com/image01.jpg",
"name": "image01.jpg",
//...other properties
}
}
For every row I want to update the thumbnail.url and replace some-url with other-url.
I'm far from being an expert in PostgreSQL (or any other DB for that matter), and after some reading I tried to run the following query in pgAdmin:
UPDATE files
SET formats = jsonb_set(formats, '{thumbnail.url}', REPLACE('{thumbnail.url}', 'some-url', 'other-url'))
And I received this error: function jsonb_set(jsonb, unknown, text) does not exist
I tried to set format jsonb_set(formats::jsonb...), tried to target '{thumbnail}' instead of '{thumbnail.url}' - always the same error.
What am I doing wrong? Or is pgAdmin really doesn't support this function? How can I do such an update with pgAdmin query tool?
We can try to use ->> to get JSON content value of url and then replace your expect value from that.
Because your url field of your JSON might be string type we need to use " to content it before cast as JSONB
jsonb_set(target jsonb, path text[], new_value jsonb [, create_missing boolean])
UPDATE files
SET formats = jsonb_set(formats, '{thumbnail,url}', CONCAT('"',REPLACE(formats->'thumbnail'->>'url','some-url','other-url'),'"')::JSONB);
sqlfiddle
The second parameter of jsonb_set() must be an array with one array element for each "path" element. So the second parameter should be '{thumbnail,url}' or more obvious: array['thumbnail', 'url']
And the third parameter must be a jsonb value, but replace returns a text, so you need to use e.g. to_jsonb() to convert the result of the replace() to a jsonb value.
And as D-Shih pointed out, you need to extract the old value using ->>. But to get the URL you need to "navigate" to it: formats -> 'thumbnail ->> 'url'
I would also add a WHERE clause so that you only update rows that actually contain a URL.
UPDATE files
SET formats = jsonb_set(formats,
'{thumbnail,url}',
to_jsonb(replace(formats -> 'thumbnail' ->> 'url', 'some-url', 'other-url'))
)
where (formats -> 'thumbnail') ? 'url'
This seems like it would be straightforward to do but I just can not figure it out. I have a query that returns an ARRAY of strings in one of the columns. I want that array to only contain unique strings. Here is my query:
SELECT
f."_id",
ARRAY[public.getdomain(f."linkUrl"), public.getdomain(f."sourceUrl")] AS file_domains,
public.getuniqdomains(s."originUrls", s."testUrls") AS source_domains
FROM
files f
LEFT JOIN
sources s
ON
s."_id" = f."sourceId"
Here's an example of a row from my return table
_id
file_domains
source_domains
2574873
{cityofmontclair.org,cityofmontclair.org}
{cityofmontclair.org}
I need file_domains to only contain unique values, IE a 'set' instead of a 'list'. Like this:
_id
file_domains
source_domains
2574873
{cityofmontclair.org}
{cityofmontclair.org}
Use a CASE expression:
CASE WHEN public.getdomain(f."linkUrl") = public.getdomain(f."sourceUrl")
THEN ARRAY[public.getdomain(f."linkUrl")]
ELSE ARRAY[public.getdomain(f."linkUrl"), public.getdomain(f."sourceUrl")]
END
I have a table named Test and in that one column (Subject) contains JSON values.
This is the query which i am using
select Name,Subject
from Test
where id =1;
And the following are the JSON values present inside table.
{
"subject":{
"Maths":"20",
"Physics":"21",
"English":"22"
},
"Staff":{
"English":"Anna",
"maths":"Rahul",
"Physics":"John"
}
}
Now my question is how to write a query to get English mark from JSON value.
Expected o/p is 22.
I am new to postgres, can any one help me in this thanks in advance
You can combine the -> and ->> operators
select Name,Subject, subject -> 'subject' ->> 'English' as english_mark
from Test
where id =1;
Alternatively use the #>> operator where you provide the path to the element you want as an array of keys:
select Name,Subject, subject #>> '{subject, English}' as english_mark
from Test
where id =1;
If I have a jsonb column called value with fields such as:
{"id": "5e367554-bf4e-4057-8089-a3a43c9470c0",
"tags": ["principal", "reversal", "interest"],,, etc}
how would I find all the records containing given tags, e.g:
if given: ["reversal", "interest"]
it should find all records with either "reversal" or "interest" or both.
My experimentation got me to this abomination so far:
select value from account_balance_updated
where value #> '{}' :: jsonb and value->>'tags' LIKE '%"principal"%';
of course this is completely wrong and inefficient
Assuming you are using PG 9.4+, you can use the jsonb_array_elements() function:
SELECT DISTINCT abu.*
FROM account_balance_updated abu,
jsonb_array_elements(abu.value->'tags') t
WHERE t.value <# '["reversal", "interest"]'::jsonb;
As it turned out you can use cool jsonb operators described here:
https://www.postgresql.org/docs/9.5/static/functions-json.html
so original query doesn't have to change much:
select value from account_balance_updated
where value #> '{}' :: jsonb and value->'tags' ?| array['reversal', 'interest'];
in my case I also needed to escape the ? (??|) because I am using so called "prepared statement" where you pass query string and parameters to jdbc and question marks are like placeholders for params:
https://docs.oracle.com/javase/tutorial/jdbc/basics/prepared.html
I have a table where I have added a new column, and I want to write a SQL statement to update that column based on existing information. Here are the two tables and the relevant columns
'leagues'
=> id
=> league_key
=> league_id (this is the new column)
'permissions'
=> id
=> league_key
Now, what I want to do, in plain English, is this
Set leagues.league_id to be permissions.id for each value of permissions.league_key
I had tried SQL like this:
UPDATE leagues
SET league_id =
(SELECT id FROM permissions WHERE league_key =
(SELECT distinct(league_key) FROM leagues))
WHERE league_key = (SELECT distinct(league_key) FROM leagues)
but I am getting an error message that says
ERROR: more than one row returned by a subquery used as an expression
Any help for this would be greatly appreciated
Based on your requirements of
Set leagues.league_id to be permissions.id for each value of permissions.league_key
This does that.
UPDATE leagues
SET league_id = permissions_id
FROM permissions
WHERE permissions.league_key = leagues.league_key;
When you do a subquery as an expression, it can't return a result set. Your subquery must evaluate to a single result. The error that you are seeing is because one of your subqueries returns more than one value.
Here is the relevant documentation for pg84: