I have a Postgres JSONB data which contains an ARRAY of type NUMERIC. I want to extract this ARRAY and store it in a variable of type NUMERIC[]. Here's is my JSONB object.
{
"userIds": [
101,102,103
],
"userRole": {
"id": "1",
"name": "Administrator"
}
}
How can I extract userIds from this JSONB object and store them in NUMERIC[] as I have to iterate on this NUMERIC[]?
Any help would be highly appreciated.
One way is to extract the ids with jsonb_array_elements, parse them to the right data type and aggregate them again in an array, e.g.:
SELECT array_agg(id) FROM (
SELECT
(jsonb_array_elements('{
"userIds": [101,102,103],
"userRole": {
"id": "1",
"name": "Administrator"
}
}'::jsonb->'userIds')::numeric)) j(id);
array_agg
---------------
{101,102,103}
(1 row)
If you want to iterate over these values as rows in your resultset, don't bother with the outer query:
SELECT
jsonb_array_elements('{
"userIds": [101,102,103],
"userRole": {
"id": "1",
"name": "Administrator"
}}'::jsonb->'userIds')::numeric;
jsonb_array_elements
----------------------
101
102
103
(3 rows)
Related
I have a jsonb column with the following structure:
{
"key1": {
"type": "...",
"label": "...",
"variables": [
{
"label": "Height",
"value": 131315.9289,
"variable": "myVar1"
},
{
"label": "Width",
"value": 61085.7525,
"variable": "myVar2"
}
]
},
}
I want to query for the average height across all rows. The top-level key values are unknown, so I have something like this:
select id,
avg((latVars ->> 'value')::numeric) as avg
from "MyTable",
jsonb_array_elements((my_json_field->jsonb_object_keys(my_json_field)->>'variables')::jsonb) as latVars
where my_json_field is not null
group by id;
It's throwing the following error:
ERROR: set-returning functions must appear at top level of FROM
Moving the jsonb_array_elements function above MyTable in the FROM clause doesn't work.
I'm following the basic advice found in this SO answer to no avail.
Any advice?
jsonb_array_elements is not relevant until my_json_field is a json array at the top level.
You can use instead the jsonb_path_query function based on the jsonpath language if postgres >= 12 :
select id
, avg(v.value :: numeric) as avg
from "MyTable"
, jsonb_path_query(my_json_field, '$.*.variables[*] ? (#.label == "Height").value') AS v(value)
where my_json_field is not null
group by id;
I have a Table containing 3 columns
(ID, Content, Date), where the Content column have values in json format as shown below:
{
"Id": "9999",
"Name": "PETERPAN",
"SubContent": [
{
"subcontent1": "ABC",
"subcontent2": "123"
}
[
}
How can I convert it into tabular format using SQL Query?
Use LATERAL FLATTEN to get the key/value pairs as separate rows:
with t as (
select parse_json('{
"Id": "9999",
"Name": "PETERPAN",
"SubContent":
{
"subcontent1": "ABC",
"subcontent2": "123"
}
}') col
)
select col:Id as id, col:Name as name, sc.key, sc.value
from t, lateral flatten( input => col:SubContent ) sc;
The result is
ID NAME KEY VALUE
9999 PETERPAN subcontent1 ABC
9999 PETERPAN subcontent2 123
I'm trying to fetch second max date json data from an json column..
Here is jsonb column
--------
value
--------
{
"id": "90909",
"records": [
{
"name":"john",
"date": "2016-06-16"
},
{
"name":"kiran",
"date": "2017-06-16"
},
{
"name":"koiy",
"date": "2018-06-16"
}
]
}
How to select the second maximum date json object in the jsonb column..
expected output:-
{
"name":"kiran",
"date": "2017-06-16"
}
and if we have only one object inside the records means that will be the second max date
and any suggestions would also helpful..
one way of doing it could be, get all the dates in an array, then sort the array in DESC and then get the second date. all these steps can be done in a single query
I am trying to build a query which combines rows of one table into a JSON array, I then want that array to be part of the return.
I know how to do a simple query like
SELECT *
FROM public.template
WHERE id=1
And I have worked out how to produce the JSON array that I want
SELECT array_to_json(array_agg(to_json(fields)))
FROM (
SELECT id, name, format, data
FROM public.field
WHERE template_id = 1
) fields
However, I cannot work out how to combine the two, so that the result is a number of fields from public.template with the output of the second query being one of the returned fields.
I am using PostGreSQL 9.6.6
Edit, as requested more information, a definition of field and template tables and a sample of each queries output.
Currently, I have a JSONB row on the template table which I am using to store an array of fields, but I want to move fields to their own table so that I can more easily enforce a schema on them.
Template table contains:
id
name
data
organisation_id
But I would like to remove data and replace it with the field table which contains:
id
name
format
data
template_id
At the moment the output of the first query is:
{
"id": 1,
"name": "Test Template",
"data": [
{
"id": "1",
"data": null,
"name": "Assigned User",
"format": "String"
},
{
"id": "2",
"data": null,
"name": "Office",
"format": "String"
},
{
"id": "3",
"data": null,
"name": "Department",
"format": "String"
}
],
"id_organisation": 1
}
This output is what I would like to recreate using one query and both tables. The second query outputs this, but I do not know how to merge it into a single query:
[{
"id": 1,
"name": "Assigned User",
"format": "String",
"data": null
},{
"id": 2,
"name": "Office",
"format": "String",
"data": null
},{
"id": 3,
"name": "Department",
"format": "String",
"data": null
}]
The feature you're looking for is json concatenation. You can do that by using the operator ||. It's available since PostgreSQL 9.5
SELECT to_jsonb(template.*) || jsonb_build_object('data', (SELECT to_jsonb(field) WHERE template_id = templates.id)) FROM template
Sorry for poorly phrasing what I was trying to achieve, after hours of Googling I have worked it out and it was a lot more simple than I thought in my ignorance.
SELECT id, name, data
FROM public.template, (
SELECT array_to_json(array_agg(to_json(fields)))
FROM (
SELECT id, name, format, data
FROM public.field
WHERE template_id = 1
) fields
) as data
WHERE id = 1
I wanted the result of the subquery to be a column in the ouput rather than compiling the entire output table as a JSON.
Let's say we have this json in our database table. I want to select value from tags. I already know how to get an array from this data but I don't know how to access array members. The question would be how do I get the first value from the array? Is there a function for this task?
{
"info": {
"type": 1,
"address": {
"town": "Bristol",
"county": "Avon",
"country": "England"
},
"tags": ["Sport", "Water polo"]
},
"type": "Basic"
}
Query I already have:
SELECT JSON_QUERY(MyTable.Data, '$.info.tags')
FROM MyTable
This returns me:
["Sport", "Water polo"]
How do I get
Sport
JSON_QUERY returns an object or array. You need JSON_VALUE to return a scalar value, eg :
SELECT JSON_VALUE(Data, '$.info.tags[0]')
from MyTable
Check the section Compare JSON_VALUE and JSON_QUERY in the docs for more examples