I have a table where i am saving data in a column of type bytea, the data is actually a JSON object.
I need to implement a filter on the JSON data.
SELECT cast(job_data::TEXT as jsonb) FROM job_details where job_data ->> "organization" = "ABC";
This query does not work.
The JSON Object looks like
{
"uid": "FdUR4SB0h7",
"Type": "Reference Data Service",
"user": "hk#ss.com",
"SubType": "Reference Data Task",
"_version": 1,
"Frequency": "Once",
"Parameters": "sdfsdfsdfds",
"organization": "ABC",
"StartDateTime": "2020-01-20T10:30:00Z"
}
You need to predicate on the converted column, also, that conversion may not necessarily work depending on encoding. Try something like this:
SELECT
*
FROM
job_details
WHERE
convert_from(job_data, 'UTF-8')::json ->> 'organization' = 'ABC';
Related
I am working on a sensitive migration. The scenario is as follows:
I have a new table that I need to populate with data
There is an existing table, which contains a column (type = json), which contains an array of objects such as:
[
{
"id": 0,
"name": "custom-field-0",
"label": "When is the deadline for a response?",
"type": "Date",
"options": "",
"value": "2020-10-02",
"index": 1
},
{
"id": 1,
"name": "custom-field-1",
"label": "What territory does this relate to?",
"type": "Dropdown",
"options": "UK, DE, SE, DK, BE, NL, IT, FR, ES, AT, CH, NO, US, SG, Other",
"value": " DE",
"index": 2
}
]
I need to essentially map these values in this column to my new table. I have worked with JSON data in PostgresQL before, where I was dealing with a single object in the JSON, but never with arrays of objects and on such a large scale.
So just to summarise, how does someone iterate every row, and every object in an array, and insert that data into a new table?
EDIT
I have been experimenting with some functions, and I found one that seems promising json_array_elements_text or json_array_elements. As this allowed me to add multiple rows to the new table using this array of objects.
However, my issue is that I need to map certain values to the new table.
INSERT INTO form_field_value ("name", "label", "inputType", "options", "form" "workspace")
SELECT <<HERE IS WHERE I NEED TO EXTRACT VALUES FROM THE JSON ARRAY>>, task.form, task.workspace
FROM task;
EDIT 2
I have been playing around some more with the above functions, but reached a slight issue.
INSERT INTO form_field_value ("name", "label", "inputType", "options", "form" "workspace")
SELECT cf ->> 'name',
(cf ->> 'label')
...
FROM jsonb_array_elements(task."customFields") AS t(cf);
My issue lies in the FROM clause, so customFields is the array of objects, but I also need to get the form and workspace attribute from this table too. Plus I a pretty sure that the FROM clause would not work anyway, as it probably will complain about the task."customFields" not being specified or something.
Here is the select statement that uses json_array_elements and a lateral join in the from clause to flatten the data.
select j ->> 'name' as "name", j ->> 'label' as "label",
j ->> 'type' as "inputType", j ->> 'options' as "options", form, workspace
from task
cross join lateral json_array_elements("customFields") as l(j);
The from clause can be less verbose
from task, json_array_elements("customFields") as l(j)
you can try to use json_to_recordset:
select * from json_to_recordset('
[
{
"id": 0,
"name": "custom-field-0",
"label": "When is the deadline for a response?",
"type": "Date",
"options": "",
"value": "2020-10-02",
"index": 1
},
{
"id": 1,
"name": "custom-field-1",
"label": "What territory does this relate to?",
"type": "Dropdown",
"options": "UK, DE, SE, DK, BE, NL, IT, FR, ES, AT, CH, NO, US, SG, Other",
"value": " DE",
"index": 2
}
]
') as x(id int, name text,label text,type text,options text,value text,index int)
for insert record you can use an sql like this:
INSERT INTO form_field_value ("name", "label", "inputType", "options", "form" "workspace")
SELECT name, label, type, options, form, workspace
FROM
task,
json_to_record(task) AS
x (id int, name text,label text,type text,options text,value text,index int)
I want to get a specific string from a column. How can I get that.
Here is the json with column name json with table name my_table
I want to fetch "extensionAttribute.simSerial": "310240000029929".
{
"name": "urn:imei:930000001801583",
"type": "DEVICE",
"sourceId": "P-n1000USCqT4",
"consumers": "CDM",
"crudStatus": {
"status": "SUCCESS",
"operation": "UPDATE"
},
"targetName": "urn:imei:930000001801583",
"deviceTypeId": "dgs11b74714f7020ctoogu3zfugc6",
"createdUserId": "a8aacc5d978d494eb54ae4243e714646",
"onboardStatus": "DONE",
"consrStatus": "",
"deviceTypeName": "performance_device_type_2",
"lwm2mPskSecret": "49443",
"createdUserName": "manager",
"bootstrapRequest": true,
"lwm2mPskIdentity": "urn:imei:930000001801583",
"boostrapPskSecret": "49443",
"deviceTypeVersion": 1,
"lastUpdatedUserId": "",
"lwm2mSecurityMode": "psk",
"consumersForUpdate": "",
"bootstrapPskIdentity": "urn:imei:930000001801583",
"pureCoapSecurityMode": "NONE",
"bootstrapSecurityMode": "psk",
"extensionAttribute.imsi": "310240000029929",
"extensionAttribute.msisdn": "310240000029929",
"extensionAttribute.simSerial": "310240000029929",
"extensionAttribute.msisdnStatus": "active"
}
Solution
You can do it as follows:
select column_name->>'extensionAttribute.simSerial' as simSerial from my_table;
where column_name is your column name in a table.
If you will have JSON with higher depth you can do something like:
column_name->'key_in_json'->'another_key_in_json'->>'last_key_in_json'
Manual
JSON Functions and Operators
PostgreSQL JSON Tutorial
SELECT * FROM some_table;
I can query to get the following results:
{
"sku0": {
"Id": "18418",
"Desc": "yes"
},
"sku1": {
"Id": "17636",
"Desc": "no"
},
"sku2": {
"Id": "206714",
"Desc": "yes"
},
"brand": "abc",
"displayName": "something"
}
First, the number of skus is not fixed. It may be sku0, sku1, sku2, sku3, sku4 ... but they all start with sku.
Then, I want to query Id with 17636 and determine whether its value of Desc is yes or no. After reading the PostgreSQL JSON Functions and Operators documentation, Depressing I didn't find a good way.
I can convert the result into a Python dictionary, and then use python's method can easily achieve my requirements.
If the requirements can also be achieved with postgresql statements, which method is more recommended than the Python dictionary?
I am not sure I completely understand what the result is you want. But if you want to filter on the Id, you need to unnest all the elements inside the JSON column:
select d.v ->> 'Desc' as description
from the_table t
cross join jsonb_each(t.data) as d(k,v)
where d.v ->> 'Id' = '17636'
You could use the new jsonpath notation of PostgreSQL v12:
SELECT data ## '$.* ? (#.Id == "17636").Desc == "yes"'
FROM some_table;
That will start with the root of data ($), find any attribute in it (*), filter only those attributes that contain an Id with value "17636", get their Desc attribute and return TRUE only if that attribute is "yes".
Nice, isn't it?
This will probably give you what you need.
select value->>'Desc' from jsonb_each('{
"sku0": {
"Id": "18418",
"Desc": "yes"
},
"sku1": {
"Id": "17636",
"Desc": "no"
},
"sku2": {
"Id": "206714",
"Desc": "yes"
},
"brand": "abc",
"displayName": "something"
}'::jsonb)
where key like 'sku%'
and value->>'Id'='17636'
Best regards,
Bjarni
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