I done
let statuses = await t.any(`SELECT DISTINCT status FROM mails`)
and got
"statuses": [
{
"status": "error"
},
{
"status": "success"
}
]
How can I get array with keys of objects ? ['error', 'success'] ?
Assuming status is a jsonb column (which it should be), you can do:
select distinct st.status
from mails m
cross join jsonb_array_elements(m.status -> 'statuses') as st(status)
If status is a json column you will need to use json_array_elements() instead
Related
There is such a data structure:
Column "recipient" type jsonb
{
"phoneNumbers": [
{
"isDefault": true,
"type": "MOBILE",
"number": "3454654645"
},
{
"isDefault": true,
"type": "MOBILE",
"number": "12423543645"
}
]
}
I need to write a search request by number. In the postgres documentation, I did not find a search by value in an array, only it is obtained by an index. It doesn't suit me
I made a query like this, it gets executed, but are there any other ways to search through an array?
SELECT *
FROM my_table
WHERE recipient -> 'phoneNumbers' #> '[{"number":3454654645}]'
That's pretty much the best way, yes.
If you have a (GIST) index on recipient the index would not be used by your condition. But the following could make use of such an index:
SELECT *
FROM my_table
WHERE recipient #> '["phoneNumbers": {"number":3454654645}]}'
If you are using Postgres 12 or later, you can also use a JSON path expression:
SELECT *
FROM my_table
WHERE recipient ## '$.phoneNumbers[*].number == "12423543645"'
If you can't pass a JSON object to your query, you can use an EXISTS sub-select:
SELECT mt.*
FROM my_table mt
WHERE EXISTS (SELECT *
FROM jsonb_array_elements_text(mt.recipient -> 'phoneNumbers') as x(element)
WHERE x.element ->> 'number' = '3454654645')
The '3454654645' can be passed as a parameter to your query. This will never make use of an index though.
Background:
I wish to locate the entire JSON document that has a condition where "state" = "new" and where length(Features.id) > 4
{
"id": "123"
"feedback": {
"Features": [
{
"state": "new"
"id": "12345"
}
]
}
}
This is what I have tried to do:
Since this is a nested document. My query looks like this:
A stackoverflow member has helped me to access the nested contents within the query, but is there a way to obtain the full document
I have used:
SELECT VALUE t.id FROM t IN f.feedback.Features where t.state = 'new' and length(t.id)>4
This will give me the ids.
My desire is to have access to the full document with this condition?
{
"id": "123"
"feedback": {
"Features": [
{
"state": "new"
"id": "12345"
}
]
}
}
Any help is appreciated
Try this
SELECT *
FROM f
WHERE
f.feedback.Features[0].state = 'new'
AND length(f.feedback.Features[0].id)>4
Here is the SELECT spec for CosmosDB for more details
https://learn.microsoft.com/en-us/azure/cosmos-db/sql-query-select
Also, check out "working with JSON" in CosmosDB notes
https://learn.microsoft.com/en-us/azure/cosmos-db/sql-query-working-with-json
If the Features array has more than 1 value, you can use EXISTS clause to search within them. See specs of EXISTS here with examples:
https://learn.microsoft.com/en-us/azure/cosmos-db/sql-query-subquery#exists-expression
Let's say I have this json in my jsonb column
{
"fields": [
{
"name": "firstName",
},
{
"name": "lastName",
},
...
}
How can I know if the "firstName" already exist?
I've tried this so far
SELECT field->>'fields'
from person where (field->'name')::jsonb ? 'firstName';
Use the containment operator #>:
select field->>'fields'
from person
where field->'fields' #> '[{"name": "firstName"}]'
you can use json_array_elements to generate fields elements so you can filter based on 'name'.
SELECT field->>'fields', obj.*
from person, jsonb_array_elements_text(field->'fields') obj
where obj = '{"name": "firstName"}'
see dbfiddle
I'm using following schema for the JSONB column of my table (named fields). There are several of these field entries.
{
"FIELD_NAME": {
"value" : "FIELD_VALUE",
"meta": {
"indexable": true
}
}
}
I need to find all the fields that contain this object
"meta": {
"indexable": true
}
Here is a naive attempt at having json_object_keys in where clause, which doesn't work, but illustrates what I'm trying to do.
with entry(fields) as (values('{
"login": {
"value": "fred",
"meta": {
"indexable": true
}
},
"password_hash": {
"value": "88a3d1c7463d428f0c44fb22e2d9dc06732d1a4517abb57e2b8f734ce4ef2010",
"meta": {
"indexable": false
}
}
}'::jsonb))
select * from entry where fields->jsonb_object_keys(fields) #> '{"meta": {"indexable": "true"}}'::jsonb;
How can I query on the value of nested object? Can I somehow join the result of json_object_keys with the table iself?
demo:db<>fiddle
First way: using jsonb_each()
SELECT
jsonb_build_object(elem.key, elem.value) -- 3
FROM
entry,
jsonb_each(fields) as elem -- 1
WHERE
elem.value #> '{"meta": {"indexable": true}}' -- 2
Expand all subobjects into one row per "field". This creates 2 columns: the key and the value (in your case login and {"meta": {"indexable": true}, "value": "fred"})
Filter the records by checking the value column for containing the meta object using the #> as you already mentioned
Recreate the JSON object (combining the key/value columns)
Second way: Using jsonb_object_keys()
SELECT
jsonb_build_object(keys, fields -> keys) -- 3
FROM
entry,
jsonb_object_keys(fields) as keys -- 1
WHERE
fields -> keys #> '{"meta": {"indexable": true}}' -- 2
Finding all keys as you did
and 3. are very similar to the first way
I have a json array similar to this structure in a column of my database -
{
"id": "123abc",
"Y/N": "Y",
"Color": "Purple",
"arr": [ {
"time": 1210.55
"person": "Sean"
"action": "yes" //The values for this field can only be 'yes', 'no, 'maybe'
},
{
"time": 1230.19
"person": "Linda"
"action": "no"
} ],
}
I need to pull all the corresponding attributes based on 2 criteria of an object in the "arr" array. I want to get the latest "arr" object based on the "time" (highest value) but only pull this index if the "action" is equal to 'no' or 'yes', so exclude all the objects when "action" = "maybe".
I have tried using a WHERE statement to have a "time" range set and ORDER BY DESC to pull the latest entry and return the entire "arr". This just returns the highest value of "time" but returns all the attributes when "action" = "maybe" but I want to return the objects with only "yes" or "no".
Here is the current query I have -
SELECT jsonb_build_object('ID', t.col -> '_id',
'Yes or No', t.col -> 'Y/N',
'arr', x.elem)
FROM tbl t
CROSS JOIN LATERAL (
SELECT elem
FROM jsonb_array_elements(t.col -> 'arr') a(elem)
WHERE a.elem -> 'time' between '1110.23' and '1514.12'
AND t.col ->> 'Color' = 'Purple'
ORDER BY a.elem -> 'time' DESC NULLS LAST
LIMIT 1
) x;
The query is returning the latest object in the array with the highest time but it is also returning objects when "action" = "maybe". I have tried adding AND a.elem -> 'action' = 'yes' after the WHERE statement but receive an error saying the Token "yes" is invalid.
Is it possible to return an object with the largest "time" that has the "action" attribute equal to "yes" or "no" only?
Your code is alternatively using -> and ->>, but it isn't using them correctly.
Lots of good details here: What is the difference between `->>` and `->` in Postgres SQL?.
Everywhere in the code using -> should be ->> if you try that in the where clause with AND a.elem ->> 'action' = 'yes' it should work.