My JSON data looks like this:
[{
"id": 1,
"payload": {
"location": "NY",
"details": [{
"name": "cafe",
"cuisine": "mexican"
},
{
"name": "foody",
"cuisine": "italian"
}
]
}
}, {
"id": 2,
"payload": {
"location": "NY",
"details": [{
"name": "mbar",
"cuisine": "mexican"
},
{
"name": "fdy",
"cuisine": "italian"
}
]
}
}]
given a text "foo" I want to return all the tuples that have this substring. But I cannot figure out how to write the query for the same.
I followed this related answer but cannot figure out how to do LIKE.
This is what I have working right now:
SELECT r.res->>'name' AS feature_name, d.details::text
FROM restaurants r
, LATERAL (SELECT ARRAY (
SELECT * FROM json_populate_recordset(null::foo, r.res#>'{payload,
details}')
)
) AS d(details)
WHERE d.details #> '{cafe}';
Instead of passing the whole text of cafe I want to pass ca and get the results that match that text.
Your solution can be simplified some more:
SELECT r.res->>'name' AS feature_name, d.name AS detail_name
FROM restaurants r
, jsonb_populate_recordset(null::foo, r.res #> '{payload, details}') d
WHERE d.name LIKE '%oh%';
Or simpler, yet, with jsonb_array_elements() since you don't actually need the row type (foo) at all in this example:
SELECT r.res->>'name' AS feature_name, d->>'name' AS detail_name
FROM restaurants r
, jsonb_array_elements(r.res #> '{payload, details}') d
WHERE d->>'name' LIKE '%oh%';
db<>fiddle here
But that's not what you asked exactly:
I want to return all the tuples that have this substring.
You are returning all JSON array elements (0-n per base table row), where one particular key ('{payload,details,*,name}') matches (case-sensitively).
And your original question had a nested JSON array on top of this. You removed the outer array for this solution - I did the same.
Depending on your actual requirements the new text search capability of Postgres 10 might be useful.
I ended up doing this(inspired by this answer - jsonb query with nested objects in an array)
SELECT r.res->>'name' AS feature_name, d.details::text
FROM restaurants r
, LATERAL (
SELECT * FROM json_populate_recordset(null::foo, r.res#>'{payload, details}')
) AS d(details)
WHERE d.details LIKE '%oh%';
Fiddle here - http://sqlfiddle.com/#!15/f2027/5
Related
I have a table source:
data
{ "results": { "rows": [ { "title": "A", "count": 61 }, { "title": "B", "count": 9 } ] }}
{ "results": { "rows": [ { "title": "C", "count": 43 } ] }}
And I want a table dest:
title
count
A
61
B
9
C
43
I found there is JSON_TO_ARRAY function that might be helpful, but got stuck how to apply it.
How to correctly flatten the json array from the table?
I have the following that works on your example but it might help you with the syntax.
In this query I created a table called json_tab with a column called jsondata.
With t as (
select table_col AS title FROM json_tab join TABLE(JSON_TO_ARRAY(jsondata::results::rows)))
SELECT t.title::$title title,t.title::$count count FROM t
I took example from the code snippet to work with Nested Arrays in a JSON Column
https://github.com/singlestore-labs/singlestoredb-samples/blob/main/JSON/Analyzing_nested_arrays.sql
Three options I came up with, which are essentially the same:
INSERT INTO dest
WITH t AS(
SELECT table_col AS arrRows FROM source JOIN TABLE(JSON_TO_ARRAY(data::results::rows))
)
SELECT arrRows::$title as title, arrRows::%count as count FROM t;
INSERT INTO dest
SELECT arrRows::$title as title, arrRows::%count as count FROM
(SELECT table_col AS arrRows FROM source JOIN TABLE(JSON_TO_ARRAY(data::results::rows)));
INSERT INTO dest
SELECT t.table_col::$title as title, t.table_col::%count as count
FROM source JOIN TABLE(json_to_array(data::results::rows)) t;
I have a column (locations) populated with something like below.
{
"unique_id": "1",
"address": {
"street_address": "100 Main St",
"city": "Pleasantville",
"state_province": "IL",
"country_code": "US"
}
}
I know how to select "unique_id" with
SELECT locations #>> '{unique_id}'
FROM table;
But how would you select, say, "street_address"?
You have a couple of options; because the JSON operators return JSON you can chain the operators:
SELECT locations -> 'address' -> 'street_address' AS way1 FROM testjson;
Alternatively you can use the operators that accept an array:
SELECT locations #> '{address,street_address}' AS otherway FROM testjson;
See this sql fiddle for a working example or the documentation for further information.
Let's say I have this json in my jsonb column
{
"fields": [
{
"name": "firstName",
},
{
"name": "lastName",
},
...
}
How can I know if the "firstName" already exist?
I've tried this so far
SELECT field->>'fields'
from person where (field->'name')::jsonb ? 'firstName';
Use the containment operator #>:
select field->>'fields'
from person
where field->'fields' #> '[{"name": "firstName"}]'
you can use json_array_elements to generate fields elements so you can filter based on 'name'.
SELECT field->>'fields', obj.*
from person, jsonb_array_elements_text(field->'fields') obj
where obj = '{"name": "firstName"}'
see dbfiddle
I'm trying to merge some nested JSON arrays without looking at the id. Currently I'm getting this when I make a GET request to /surveyresponses:
{
"surveys": [
{
"id": 1,
"name": "survey 1",
"isGuest": true,
"house_id": 1
},
{
"id": 2,
"name": "survey 2",
"isGuest": false,
"house_id": 1
},
{
"id": 3,
"name": "survey 3",
"isGuest": true,
"house_id": 2
}
],
"responses": [
{
"question": "what is this anyways?",
"answer": "test 1"
},
{
"question": "why?",
"answer": "test 2"
},
{
"question": "testy?",
"answer": "test 3"
}
]
}
But I would like to get it where each survey has its own question and answers so something like this:
{
"surveys": [
{
"id": 1,
"name": "survey 1",
"isGuest": true,
"house_id": 1
"question": "what is this anyways?",
"answer": "test 1"
}
]
}
Because I'm not going to a specific id I'm not sure how to make the relationship work. This is the current query I have that's producing those results.
export function getSurveyResponse(id: number): QueryBuilder {
return db('surveys')
.join('questions', 'questions.survey_id', '=', 'surveys.id')
.join('questionAnswers', 'questionAnswers.question_id', '=', 'questions.id')
.select('surveys.name', 'questions.question', 'questions.question', 'questionAnswers.answer')
.where({ survey_id: id, question_id: id })
}
Assuming jsonb in current Postgres 10 or 11, this query does the job:
SELECT t.data, to_jsonb(s) AS new_data
FROM t
LEFT JOIN LATERAL (
SELECT jsonb_agg(s || r) AS surveys
FROM (
SELECT jsonb_array_elements(t.data->'surveys') s
, jsonb_array_elements(t.data->'responses') r
) sub
) s ON true;
db<>fiddle here
I unnest both nested JSON arrays in parallel to get the desired behavior of "zipping" both directly. The number of elements in both nested JSON arrays has to match or you need to do more (else you lose data).
This builds on implementation details of how Postgres deals with multiple set-returning functions in a SELECT list to make it short and fast. See:
What is the expected behaviour for multiple set-returning functions in select clause?
One could be more explicit with a ROWS FROM expression, which works properly since Postgres 9.4:
SELECT t.data
, to_jsonb(s) AS new_data
FROM tbl t
LEFT JOIN LATERAL (
SELECT jsonb_agg(s || r) AS surveys
FROM ROWS FROM (jsonb_array_elements(t.data->'surveys')
, jsonb_array_elements(t.data->'responses')) sub(s,r)
) s ON true;
The manual about combining multiple table functions.
Or you could use WITH ORDINALITY to get original order of elements and combine as you wish:
PostgreSQL unnest() with element number
Assume I am using PG 9.3 and I have a post table with a json column 'meta_data':
Example content of the json column 'meta_data'
{
"content": "this is a post body",
"comments": [
{
"user_id": 1,
"content": "hello"
},
{
"user_id": 2,
"content": "foo"
},
{
"user_id": 3,
"content": "bar"
}
]
}
How can I find all the posts where the user_id = 1 from the comments array from the meta_data column?
I'm almost positive I'm implementing this incorrectly but try this
select *
from posts
where id in (
select id from (
select id,
json_array_elements(meta_data->'comments')->'user_id' as user_id
from posts
) x
where cast(user_id as varchar) = '1'
);
There's probably an array operator like #> that will remove the need for the nested select statements but I can't seem to get it to work right now.
Let me know if this is going down the correct track, I'm sure we could figure it out if required.