The documentation shows that arrays can be created as either text or integer. I did not find an example for creating an object array. An example is the items column:
CREATE TABLE cart (
_id serial PRIMARY KEY,
user_id Integer UNIQUE NOT NULL,
items varchar [],
FOREIGN KEY (user_id)
REFERENCES users (_id)
Object stored in the items array have quotes around them making them strings instead of objects. A code segment creating objects in items is shown below:
update cart
set items =
array_append(items,
'{product_id: ${cartItem.productId}, size: ${cartItem.size}, quantity: ${cartItem.quantity}}')
where _id = ${cart._id}
and user_id = ${userId}
RETURNING *
I am compelled to put quotes around the object value. As a result it is stored as a string in the column with quotes around it.
cart {
_id: 1,
user_id: 1,
items: [
'{product_id: 1, size: Small, quantity: 1}',
'{product_id: 1, size: Small, quantity: 1}',
'{product_id: 1, size: Small, quantity: 1}'
]
}
Because the items in the items column are stored as string instead of objects, I cannot correctly iterate over them in my program. For example,
items.product_id does not exist.
How do I fix this?
I wrote some examples for you
Example 1. (Insert into JSONB type using converting String to JSONB)
INSERT INTO cart
(
product_id,
quantity,
"size",
user_id,
items
)
values
(
1,
1,
'Small',
1,
'[
{"size": "Small", "quantity": 1, "product_id": 1},
{"size": "Small", "quantity": 1, "product_id": 1},
{"size": "Small", "quantity": 1, "product_id": 1}
]'::jsonb
);
Example 2. (Convert fields of selected table to JSONB using row_to_json)
select row_to_json(t1) as your_json from (
select product_id, "size", quantity from cart
) t1
Result:
your_json
--------------------------------------------
{"product_id":1,"size":"Small","quantity":1}
{"product_id":1,"size":"Small","quantity":1}
{"product_id":1,"size":"Small","quantity":1}
Example 3. (Concat all rows of type JSONB)
select jsonb_agg(row_to_json(t1)) as your_json from (
select product_id, "size", quantity from cart
) t1
Result:
your_json
---------------------------------------------------------------------------------------------------------------------------------------------------------
[{"size": "Small", "quantity": 1, "product_id": 1}, {"size": "Small", "quantity": 1, "product_id": 1}, {"size": "Small", "quantity": 1, "product_id": 1}]
Example 4. (Similar of row_to_json)
select
json_build_object('product_id', product_id, 'size', size, 'quantity', quantity) as your_json
from cart;
Result:
your_json
--------------------------------------------
{"product_id":1,"size":"Small","quantity":1}
{"product_id":1,"size":"Small","quantity":1}
{"product_id":1,"size":"Small","quantity":1}
Example 5. (Concatenate many JSONB objects using ||)
select jsonb_build_array('{"product_id":1,"size":"Small","quantity":1}'::jsonb) || jsonb_build_array('{"product_id":1,"size":"Small","quantity":1}'::jsonb) as your_json
-- or
select jsonb_build_array('{"product_id":1,"size":"Small","quantity":1}'::jsonb, '{"product_id":1,"size":"Small","quantity":1}'::jsonb) as your_json
Result:
your_json
------------------------------------------------------------------------------------------------------
[{"product_id": 1, "size": "Small", "quantity": 1}, {"product_id": 1, "size": "Small", "quantity": 1}]
Example 6. (Similar example to your update query (using concatenating JSONB types)
update cart
set
items = jsonb_build_array(items) || jsonb_build_array('{"product_id":1,"size":"Small","quantity":1}'::jsonb)
where id = 1
Result:
items
------------------------------------------------------------------------------------------------------
[{"product_id": 1, "size": "Small", "quantity": 1}, {"product_id": 1, "size": "Small", "quantity": 1}]
Recommended using JSON or JSONB types. In JSON types you can perform any operations on keys or values, such as filtering, selecting, joining. If you need you can even show JSON keys and values as table record view.
Examples:
items: '[
{"product_id": 1, "size": "Small", "quantity": 1},
{"product_id": 1, "size": "Small", "quantity": 1},
{"product_id": 1, "size": "Small", "quantity": 1}
]'
select
json_array_elements(items)->'product_id' as product_id,
json_array_elements(items)->'size' as "size",
json_array_elements(items)->'quantity' as quantity
from cart
where user_id = 1;
Result:
product_id
size
quantity
1
"Small"
1
1
"Small"
1
1
"Small"
1
Related
I have two following tables:
CREATE TABLE elements(
id INT PRIMARY KEY,
element_type INT,
api_name VARCHAR(100) UNIQUE
);
CREATE TABLE entries(
id INT PRIMARY KEY,
elements JSONB
)
entries.elements field stored a jsonb-array of elements in following format:
[
{
"id": elements.id
"type": elements.element_type
"value": <some_value>
},
{
"id": elements.id
"type": elements.element_type
"value": <some_value>
}
...
]
The value field can be one of 3 types:
Literal (i.e. "abc", 12, true)
Array of literals (i.e. ["abc", "cbd"], [12, 21])
Array of objects (i.e. [{"node_id": <uuid>, "value": "abc"}, {"node_id": <uuid>, "value": "cba"}])
And I have index (maybe incorrect)
CREATE INDEX some_idx_name
ON entries
USING GIN (elements jsonb_ops)
For example suppose that I have data in these tables:
INSERT INTO elements(id, element_type, api_name) VALUES
(1, 1, 'el_number_1'),
(2, 2, 'el_datetime'),
(3, 3, 'el_files'),
(4, 1, 'el_number_2');
INSERT INTO entries(id, elements) VALUES
(1, '[{"id": 1, "type": 1, "value": 12}, {"id": 3, "type": 3, "value": [1, 2]}]'::JSONB),
(2, '[{"id": 4, "type": 1, "value": 12}, {"id": 2, "type": 2, "value": [{"date": "20.12.2022", "time": "16:18"}]}]'::JSONB);
So if I want to find entry by elements I need to do something like this:
SELECT id
FROM entries
WHERE elements #? '$[*] ? (#.id == 4 && #.value = 12)'
But how can I find entry by value of elements which was found by api_name?
-- DOES NOT WORK (only for example what I need)
SELECT id
FROM entries
WHERE elements #? '$[*] ? (#.id == (SELECT id FROM elements WHERE api_name = 'el_number_2') && #.value = 12)'
Fiddle link
I have a table that looks somthing like the following:
id
name
category
specs (jsonb)
1
product1
phones
{ "brand": "brand1", "color": "red", "size": 5, "memory": "8GB"}
2
product2
phones
{ "brand": "brand1", "color": "white", "size": 7, "memory": "8GB"}
3
product3
laptops
{ "brand": "brand20", "storage": "SSD", "os": "os1" , "memory": "32GB"}
My desired output given a specific category
{
"brand": {
"brand1": 1,
"brand2": 1
},
"color": {
"red": 1,
"white": 5,
},
"memory": {
"8gb": 2,
}
}
Blow out the specs column with jsonb_each_text(), calculate the counts, and then reassemble with jsonb_object_agg() (the first two CTEs could be combined into one, but I left them verbose for illustration):
with blowout as (
select s.category, j.key, j.value
from somthing s
cross join lateral jsonb_each_text(s.specs) as j(key, value)
), counts as (
select category, key, value, count(1) as cnt
from blowout
group by category, key, value
), agg_specs as (
select category, key, jsonb_object_agg(value, cnt) as counts
from counts
group by category, key
)
select category, jsonb_object_agg(key, counts) as output
from agg_specs
group by category
;
db<>fiddle here
I have a question regarding jsonb in postgresql.
I have a table that has a column of type jsonb, where I store a list of integers.
For example list_integers column:
[1, 2, 3, 4]
I want to add a new column in this table, and insert in this column the same IDs, but the form would be list of objects, where the ID field corresponds to the integer.
For example list_ids column:
[{"id": 1}, {"id": 2}, {"id": 3}, {"id": 4}]
What would be the best way to do this?
To transform:
test=> SELECT jsonb_agg(jsonb_build_object('id', id))
test-> FROM jsonb_array_elements(jsonb '[1, 2, 3, 4]') id;
jsonb_agg
----------------------------------------------
[{"id": 1}, {"id": 2}, {"id": 3}, {"id": 4}]
(1 row)```
So I have Postgres DB table 'purchases' with columns 'id' and 'receipt'. 'id' is primary int column, the value in column 'receipt' is jsonb and can look like this:
{
"shop_name":"some_shop_name",
"items": [
{
"name": "foo",
"spent": 49,
"quantity": 1
},
{
"name": "bar",
"price": 99,
"quantity": 2
},
{
"name": "abc",
"price": 999,
"quantity": 1
},
...
]
}
There can be varied amount of items in receipt.
In the end I need to write a query so the resulting table contains purchase id and amount spent on all bar for every purchase in table as such:
id
spent
1
198
..
...
My issue:
I can't figure out how to work with jsonb inside select query along regular columns in the resulting table, I guess query should be structured as this:
SELECT p.id, %jsonb_parsing_result_here% AS spent
FROM purchases p
It's blocking me from moving further with iterating through items in FOR cycle (or maybe using another way).
You can unnest the items from the receipt column with a lateral join and the jsonb_array_elements function like:
SELECT p.id, SUM((item->>'price')::NUMERIC)
FROM purchases p,
LATERAL jsonb_array_elements(p.receipt->'items') r (item)
GROUP BY p.id
It's also possible to add a where condition, for example:
WHERE item->>'name' = 'bar
I have some nested JSONB object/arrays that I want to update/insert into array completely when a given set of values match.
I've tried this command UPDATE asset SET detail = jsonb_set(detail, '{"date": "01/01/2019"}', '{"name": "ABC", "date": "01/01/2019"}');, but doesn't work since the command is looking for an index and using || simply appends the new object into the array instead of replacing it.
Schemas
Table
CREATE TABLE asset (
id uuid NOT NULL DEFAULT uuid_generate_v1(),
detail jsonb NULL,
events_connected jsonb NULL
);
JSONB Schemas
[{
"name": "Stackoverflow",
"date": "01/01/2019"
}]
A little more in depth
[{
"id": "12345",
"events": [{"type": 0, "date": "01/01/01", "ratio": 1.0}]
}]
EDIT:
I've played around with this code which almost works, but it updates all rows with the new object instead of simply inserting/updating the event id and keys that matches. The sub query that finds the matching params seem to work.
update
asset
set
events_connected =
jsonb_set(
events_connected,
array[elem_index::text, 'events', nested_elem_index::text],
'{"type": 2, "ratio": 5.0, "tax": 1, "date": "01/02/2019"}'::jsonb,
true)
from (
select
(pos - 1) as "elem_index",
(pos2 - 1) as "nested_elem_index",
elem->>'id' as "id"
from
asset,
jsonb_array_elements(events_connected) with ordinality arr(elem, pos),
jsonb_array_elements(elem->'events') with ordinality arr2(elem2, pos2)
WHERE
elem->>'id' = '12345' AND
elem2->>'type' = '1' AND
elem2->>'date' = '01/02/2019'
) sub
WHERE
sub."elem_index" IS NOT NULL AND sub."nested_elem_index" IS NOT NULL;
Fiddle: https://dbfiddle.uk/?rdbms=postgres_11&fiddle=1b3f3b0c7a9f0adda50c54011880b61d