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 am banging my head head here for the past 2 hours with all the available JSON_... functions in BigQuery. I've read quite a few questions here but no matter why I try, I never succeed in extracting the "amounts" from my JSON below.
This is my JSON stored in a BQ column:
{
"lines": [
{
"id": "70223039-83d6-463d-a482-7ce4d50bf0fc",
"charges": [
{
"type": "price",
"amount": 50.0
},
{
"type": "discount",
"amount": -40.00
}
]
},
{
"id": "70223039-83d6-463d-a482-7ce4d50bf0fc",
"charges": [
{
"type": "price",
"amount": 20.00
},
{
"type": "discount",
"amount": 0.00
}
]
}
]
}
Imagine the above being an order containing multiple items.
I am trying to get a sum of all amounts => 50-40+20+0. The result needs to be 30 = the total order price.
Is it possible to pull all the amount values and then have them summed up just via SQL without any custom JS functions? I guess the summing is the easy part - getting the amounts into an array is the challenge here.
Use below
select (
select sum(cast(json_value(charge, '$.amount') as float64))
from unnest(json_extract_array(order_as_json, '$.lines')) line,
unnest(json_extract_array(line, '$.charges')) charge
) total
from your_table
if applied to sample data in y our question - output is
I have a simple string and hash stored in redis
get test
"1"
hget htest first
"first hash"
I'm able to see the "table" test, but there are no columns
trino> show columns from redis.default.test;
Column | Type | Extra | Comment
--------+------+-------+---------
(0 rows)
and obviously I can't get result from select
trino> select * from redis.default.test;
Query 20210918_174414_00006_dmp3x failed: line 1:8: SELECT * not allowed from relation
that has no columns
I see in the documentation that I might need to create a table definition file, but I wasn't able to create one that will work.
I had few variations of this, but this is the one for example:
{
"tableName": "test",
"schemaName": "default",
"value": {
"dataFormat": "json",
"fields": [
{
"name": "number",
"mapping": 0,
"type": "INT"
}
]
}
}
any idea what am I doing wrong?
I focused on the string since it's simpler, but I also need to query the hash
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.
I am new to MongoDb and have a query which I am struggling with..
I have a collection of reported users which looks like this:
{
"_id": 1,
"userId": 1,
"reason": "some reason",
"date": "2017-07-22"
}
I need a query which will add to each report the number of reports for that userId.
meaning if the collection has 3 records with userId=1. the query will return three records and each of them will also include a field
count=3 meaning the record above will now look like this:
{
"_id": 1
"userId": 1,
"reason": "some reason",
"date": "2017-07-22",
"count": 3
}
I tried using $project and $addFields aggregations but was not able to add a field which is a result of a query over the whole collection.
any ideas?
The answer provided by Veeram is correct, just that if you are running mongodb version less than 3.6, in the last stage of aggregate you might want to replace the $replaceRoot operator with a $project
aggregate([
{$group:{_id:"$userId", "data":{"$push":"$$ROOT"}, count:{$sum:1} } },
{"$unwind":"$data"},
{$project:{_id:"$data._id", userId:"$data.userId", reason:"$data.reason", date:"$data.date", count:1}}
])