PSQL - Query to transpose JSONB element - postgresql

I have a jsonb object like this:
{
"applicants": [
{
"last_name": "ss",
"first_name": "ss",
"age": 31
},
{
"last_name": "kk",
"first_name": "kk",
"age": 32
}
]
}
I want to convert it to.
{
"applicants": [
{
"last_name": "ss",
"data": {
"first_name": "ss",
"age": 31
}
},
{
"last_name": "kk",
"data": {
"first_name": "kk",
"age": 32
}
}
]
}
I have done a similar thing using jsonb_array_elements and jsonb_build_object before, but I can't figure out how I would create a new data object inside each object, and transpose the fields into it.
Is it possible to write this in plain psql query?
Thanks.

I have to point out that Postgres is not the best tool for modifying JSON data structures, and if you feel the need to do so, it probably means that your solution is in general not optimal. While Postgres has the necessary features to do this, I wouldn't want to maintain code that contains queries like the following.
update my_table set
json_col = (
select
jsonb_build_object(
'applicants',
jsonb_agg(
elem- 'first_name'- 'age' || jsonb_build_object(
'data',
jsonb_build_object(
'first_name',
elem->'first_name',
'age',
elem->'age'
)
)
)
)
from jsonb_array_elements(json_col->'applicants') as arr(elem)
)
Test it in db<>fiddle.

Related

Remove entire json object from JSON array

I'm trying to update the list of contacts by deleting whatever contact is requested to be deleted by user input. In other words, trying to remove an entire JSON object from a JSON array in my PostgreSQL database from a Node.js script, but I get error
error: null value in column "info" of relation "user_emails" violates
not-null constraint
I double-checked and the value and everything is there. When I try it here online it works, but on my server it returns the error. How can I fix this?
DROP table if exists user_emails;
CREATE table user_emails (
id serial not null PRIMARY KEY,
info jsonb NOT NULL
);
insert into user_emails(info) values('{
"userid": "4",
"mailbox": "johndoe#example.com",
"contacts": [
{
"id": "ghr3gk8dez4",
"email": "janedoe#gmail.com",
"last_name": "Doe",
"first_name": "Jane",
"date_created": "2022-05-08T20:52:47.967Z"
},
{
"id": "th2lypvoxpr1652045110763",
"email": "aldoe#gmail.com",
"last_name": "Doe",
"first_name": "Al",
"date_created": "2022-05-08T21:25:10.763Z"
},
{
"id": "ld123tqicmj1652045372671",
"email": "stdoe#gmail.com",
"last_name": "Doe",
"first_name": "Stella",
"date_created": "2022-05-08T21:29:32.671Z"
},
{
"id": "1ltbrpbj8xf1652045768004",
"email": "mdoe#mail.com",
"last_name": "Doe",
"first_name": "Marta",
"date_created": "2022-05-08T21:36:08.004Z"
},
{
"id": "1dgntfwvsmf1652045832589",
"email": "nala#mail.com",
"last_name": "La",
"first_name": "Na",
"date_created": "2022-05-08T21:37:12.589Z"
},
{
"id": "ll3z1n0jkhc1652045984538",
"email": "bdoe#mail.com",
"last_name": "doe",
"first_name": "bruno",
"date_created": "2022-05-08T21:39:44.538Z"
},
{
"id": "kzr996xxxt1652046050118",
"email": "pp#mail.com",
"last_name": "Perf",
"first_name": "Perf",
"date_created": "2022-05-08T21:40:50.118Z"
},
{
"id": "41bovnvsihq1652046121940",
"email": "mmd#mm.com",
"last_name": "Doe",
"first_name": "Melinda",
"date_created": "2022-05-08T21:42:01.940Z"
},
{
"id": "tnjlj4dcg2b1652046154937",
"email": "keke#j.com",
"last_name": "Kee",
"first_name": "Kee",
"date_created": "2022-05-08T21:42:34.937Z"
},
{
"id": "hor0wafkuj1652046684582",
"email": "jojo#mail.com",
"last_name": "Jo",
"first_name": "Jo",
"date_created": "2022-05-08T21:51:24.582Z"
}
],
"auto_reply": false,
"email_name": "johndoe",
"signatures": [],
"domain_name": "example.com",
"date_created": "2022-05-08T20:39:54.881Z",
"forward_email": [],
"auto_reply_messages": []
}');
this is my UPDATE
UPDATE user_emails SET info = (SELECT jsonb_agg(j)
FROM jsonb_array_elements(user_emails.info->'contacts') as t(j)
WHERE j ->> 'id' not in ('ghr3gk8dez4'));
SELECT * FROM user_emails;
jsonb_agg, like so many other aggregate functions, returns NULL if there are no rows to aggregate. You might be looking to COALESCE it to an empty array instead:
UPDATE user_emails
SET info = jsonb_set(
user_emails.info,
'{contacts}',
COALESCE(
(SELECT jsonb_agg(j)
FROM jsonb_array_elements(user_emails.info->'contacts') as t(j)
WHERE j ->> 'id' not in ('ghr3gk8dez4')
),
'[]'::jsonb
)
);
I don't think there is an efficient way to do that using only built-in functions.
There is an operator #- that removes an element by specifying the path, e.g. info #- '{contacts, 0}' would do what you want. However, it's not straight forward to build such a "path array" directly.
I would write a function that finds the index of the contact to be deleted and generates the path array:
create or replace function find_entry(p_info jsonb, p_id text)
returns text[]
as
$$
select array['contacts', (idx - 1)::text]
from jsonb_array_elements(p_info -> 'contacts') with ordinality as t(element, idx)
where t.element ->> 'id' = p_id
limit 1;
$$
language sql;
The -1 is necessary because SQL uses 1-based numbering, but in JSON arrays start at zero.
With that function you can then do:
update user_emails
set info #- find_entry(info, 'ghr3gk8dez4')
where ...

PostgresSQL nested jsonb update value of complex key/value pairs

Starting out with JSONB data type and I'm hoping someone can help me out.
I have a table (properties) with two columns (id as primary key and data as jsonb).
The data structure is:
{
"ProductType": "ABC",
"ProductName": "XYZ",
"attributes": [
{
"name": "Color",
"type": "STRING",
"value": "Silver"
},
{
"name": "Case",
"type": "STRING",
"value": "Shells"
},
...
]
}
I would like to update the value of a specific attributes element by name for a row with a given id. For example, for the element with "name"="Case" change the value to "Glass". So it ends up like
{
"ProductType": "ABC",
"ProductName": "XYZ",
"attributes": [
{
"name": "Color",
"type": "STRING",
"value": "Silver"
},
{
"name": "Case",
"type": "STRING",
"value": "Glass"
},
...
]
}
Is this possible with this structure using SQL?
I have created table structure if any of you would like to give it a shot.
dbfiddle
Use the jsonb concatenation operator, ||, to replace keys on the fly:
WITH properties (id, data) AS (
values
(1, '{"ProductType": "ABC","ProductName": "XYZ","attributes": [{"name": "Color","type": "STRING","value": "Silver"},{"name": "Case","type": "STRING","value": "Shells"}]}'::jsonb),
(2, '{"ProductType": "ABC","ProductName": "XYZ","attributes": [{"name": "Color","type": "STRING","value": "Red"},{"name": "Case","type": "STRING","value": "Shells"}]}'::jsonb)
)
SELECT id,
data||
jsonb_build_object(
'attributes',
jsonb_agg(
case
when attribs->>'name' = 'Case' then attribs||'{"value": "Glass"}'::jsonb
else attribs
end
)
) as data
FROM properties m
CROSS JOIN LATERAL JSONB_ARRAY_ELEMENTS(data->'attributes') as a(attribs)
GROUP BY id, data
Updated fiddle

Search inside array of array in JSONB column in Postgresql

I have a JSONB column in my PostgreSQL database. The data looks like this:
{
"cars":
[
{
"id": 1,
"brand": "BMW"
"parts":
[
{
"partId": 5,
"type": "battery"
}
]
},
{
"id": 2,
"brand": "Mercedes"
"parts":
[
{
"partId": 5,
"type": "battery"
},
{
"partId": 6,
"type": "engine"
}
]
}
]
}
Is there any way that I can search for all cars that have a part with type "battery"? How can I search inside of cars array and then inside of the parts array of each car element?
As it's not clear in your question that what output you want. So I am assuming that you want id and brand name in output:
so you try this:
select distinct x.y->>'id', x.y->>'brand'
from test
cross join lateral jsonb_array_elements(data->'cars') x(y)
cross join lateral jsonb_array_elements(x.y->'parts') a(b)
where a.b->>'type'='battery'
DEMO

Get size of an array of strings in PSQL

I'm having some difficulty using the array_length function in psql.
I have a json object that looks like this when a call a function named test_function:
{
"outer": [
{
"keys": {
"id": 5
},
"name": "Joe Bloggs",
"age": "16",
"new_rels": [
"a6h922ao-621y-230p-52bk-t6i84rr3vo6g"
],
"old_rels": [
"9c8b67bf-871e-4004-88be-9a68dae3a86f",
"e6a15929-4aab-4af6-903a-8f8c09bef572"
],
"s_id": 1
}
],
"total": 0,
}
I am trying to get the length of new_rels and old_rels but having some difficulty, possibly due to it being an array of strings.
I have tried this:
select array_length(r->'updates'->0->>'new_rels',1)::bigint from test_function(1) r
But I am getting the following error:
No function matches the given name and argument types. You might need to add explicit type casts
I've even tried simplifying it and doing something like this but it doesn't work with the double quotes - if I change manually to single quotes it does word:
select array_length('["90faa4b9-23fe-4bde-81e7-4326e7356cde", "d642157c-8a55-44de-ac88-ddaa3ab02bb0"]',1);
You want to use the jsonb_array_length() function for jsonb data. The array_length() function is for native arrays such as text[].
with invars as (
select '{
"outer": [
{
"keys": {
"id": 5
},
"name": "Joe Bloggs",
"age": "16",
"new_rels": [
"a6h922ao-621y-230p-52bk-t6i84rr3vo6g"
],
"old_rels": [
"9c8b67bf-871e-4004-88be-9a68dae3a86f",
"e6a15929-4aab-4af6-903a-8f8c09bef572"
],
"s_id": 1
}
],
"total": 0
}'::jsonb as r
)
select jsonb_array_length(r->'outer'->0->'new_rels'),
jsonb_array_length(r->'outer'->0->'old_rels')
from invars;
jsonb_array_length | jsonb_array_length
--------------------+--------------------
1 | 2
(1 row)
Also, you had an extra comma after the total key.

Extracting info out of lists inside a jsonb

I have a with a jsonb column called jsonb that contains data in the following format.
{
"stuff": [
{
"name": "foo",
"percent": "90.0000"
},
{
"name": "bar",
"percent": "10.0000"
}
],
"countries": [
{
"name": "USA",
"value": "30"
},
{
"name": "Canada",
"value": "25"
},
{
"name": "Mexico",
"value": "20"
},
{
"name": "Ecuador",
"value": "10"
}
]
}
I am having a lot of trouble working with this data. Specifically what I want to do is find all the different values "name" can have in "stuff" as well as in "countries", kind of like a SELECT distinct.
But my problem is that I can't seem to extract anything useful from this jsonb. My approach so far was to do
SELECT jsonb->>'stuff' FROM table, but this only gave me a column of type text which contained [{"name": "foo","percent": "90.0000"},{"name": "bar","percent": "10.0000"}].
But since this is text I can't really do anything with it. I also tried SELECT jsonb_array_elements_text(jsonb) FROM table but that returned the following Error:
ERROR: cannot extract elements from an object
SQL state: 22023
Any help with working with this format of data is greatly appreciated!
You need to unnest each array separately and then create a union on the result of those two steps:
select c.x ->> 'name'
from the_table
cross join lateral jsonb_array_elements(json_column -> 'countries') as c(x)
union
select s.x ->> 'name'
from the_table
cross join lateral jsonb_array_elements(json_column -> 'stuff') as s(x);
Online example: https://rextester.com/ZEOIXF91294