I've a json object in my postgres db, which looks like as given below
{"Actor":[{"personName":"Shashi Kapoor","characterName":"Prem"},{"personName":"Sharmila Tagore","characterName":"Preeti"},{"personName":"Shatrughan Sinha","characterName":"Dr. Amar"]}
Edited (from editor: left the original because it is an invalid json, in my edit I fixed it)
{
"Actor":[
{
"personName":"Shashi Kapoor",
"characterName":"Prem"
},
{
"personName":"Sharmila Tagore",
"characterName":"Preeti"
},
{
"personName":"Shatrughan Sinha",
"characterName":"Dr. Amar"
}
]
}
the name of the column be xyz and I've a corresponding content_id.
I need to retrieve content_ids that have Actor & personName = Sharmila Tagore.
I tried many queries, among those these two where very possible query to get but still i didn't get.
SELECT content_id
FROM content_table
WHERE cast_and_crew #>> '{Actor,personName}' = '"C. R. Simha"'
.
SELECT cast_and_crew ->> 'content_id' AS content_id
FROM content_table
WHERE cast_and_crew ->> 'Actor' -> 'personName' = 'C. R. Simha'
You should use jsonb_array_elements() to search in a nested jsonb array:
select content_id, value
from content_table,
lateral jsonb_array_elements(cast_and_crew->'Actor');
content_id | value
------------+-----------------------------------------------------------------
1 | {"personName": "Shashi Kapoor", "characterName": "Prem"}
1 | {"personName": "Sharmila Tagore", "characterName": "Preeti"}
1 | {"personName": "Shatrughan Sinha", "characterName": "Dr. Amar"}
(3 rows)
Column value is of the type jsonb so you can use ->> operator for it:
select content_id, value
from content_table,
lateral jsonb_array_elements(cast_and_crew->'Actor')
where value->>'personName' = 'Sharmila Tagore';
content_id | value
------------+--------------------------------------------------------------
1 | {"personName": "Sharmila Tagore", "characterName": "Preeti"}
(1 row)
Note, if you are using json (not jsonb) use json_array_elements() of course.
Related
The data in the table events with column attributes is in json and looks like this -
{"event_volunteer_requests":{"1":{"volunteertypeid":250,"volunteer_needed_count":50,"cc_email":""},"2":{"volunteertypeid":249,"volunteer_needed_count":30,"cc_email":""}}}
So the context is that i want to show the events with volunteertypeid present in the attributes. There are many volunteers., this is just sample data.
I've been using the query below
SELECT
*
FROM `events`
WHERE `zoneid` = 27
AND `isactive` = 1
AND JSON_CONTAINS(`attributes` -> '$.event_volunteer_requests[*].volunteertypeid', '249');
I just can't make this work and i've scorched the internet for hours. Any guidance would be appreciated.
Your JSON structure uses object syntax ({"key": "value"}), but you seem to want to use it as a JSON array (["value", "value", ...]).
The [*] syntax in JSON paths works for JSON arrays, not for JSON objects.
If your JSON document must be nested object syntax:
{
"event_volunteer_requests": {
"1": {
"cc_email": "",
"volunteertypeid": 250,
"volunteer_needed_count": 50
},
"2": {
"cc_email": "",
"volunteertypeid": 249,
"volunteer_needed_count": 30
}
}
}
Then you can do what you want this way:
SELECT t.id, t.volunteertypeid
FROM (
SELECT j.id, JSON_EXTRACT(a.attributes, CONCAT('$.event_volunteer_requests."', j.id, '".volunteertypeid')) AS volunteertypeid
FROM (SELECT '{"event_volunteer_requests":{"1":{"volunteertypeid":250,"volunteer_needed_count":50,"cc_email":""},"2":{"volunteertypeid":249,"volunteer_needed_count":30,"cc_email":""}}}' as attributes) AS a
CROSS JOIN JSON_TABLE(JSON_KEYS(a.attributes, '$.event_volunteer_requests'), '$[*]' COLUMNS (id INT PATH '$')) AS j
) AS t
WHERE t.volunteertypeid = 249;
Result:
+------+-----------------+
| id | volunteertypeid |
+------+-----------------+
| 2 | 249 |
+------+-----------------+
The JSON_TABLE() function requires MySQL 8.0. If you use MySQL 5.7, you must upgrade.
I have a table with a column of jsonb type, the JSON object is of key:value pairs, the problem is, I need to update one of the keys to contain a UUID instead of the original value.
The update statement I'm using:
UPDATE
public.applications a
SET
data = jsonb_set(data, '{id}', (SELECT b.uuid FROM public.devices b WHERE b.id = (a.data ->> 'id')::integer)::text)
Postgres returns the following error:
ERROR: function jsonb_set(jsonb, unknown, text) does not exist
I've tried to cast the value to different data types, but with same result.
Sample data
id | data
---------
1 | {"id": 1}
2 | {"id": 2}
Expected output
id | data
---------
1 | {"id": device_uuid_here}
2 | {"id": device_uuid_here}
DB_VERSION: PostgreSQL12.12
UPDATE public.applications a
SET data = jsonb_set(data, '{id}',
(SELECT '"'||b.uuid::text||'"' FROM public.devices b
WHERE b.id = (a.data ->> 'id')::integer)::jsonb);
I have a column which contains a JSON value of different lengths
["The Cherries:2.50","Draw:3.25","Swansea Jacks:2.87"]
I want to split them and store into a JSON like so:
[
{
name: "The Cherries",
odds: 2.50
},
{
name: "Draw",
odds: 3.25
},
{
name: "Swansea",
odds: 2.87
},
]
What I did right now is looping and splitting them in the UI which to me is quite heavy for the client. I want to parse and split them all in a single query.
If you are running MySQL 8.0, you can use json_table() to split the original arrayto rows, and then build new objects and aggregate them with json_arrayagg().
We need a primary key column (or set of columns) so we can properly aggreate the generated rows, I assumed id:
select
t.id,
json_arrayagg(json_object(
'name', substring(j.val, 1, locate(':', j.val) - 1),
'odds', substring(j.val, locate(':', j.val) + 1)
)) new_js
from mytable t
cross join json_table(t.js, '$[*]' columns (val varchar(500) path '$')) as j
group by t.id
Demo on DB Fiddle
Sample data:
id | js
-: | :-------------------------------------------------------
1 | ["The Cherries:2.50", "Draw:3.25", "Swansea Jacks:2.87"]
Query results:
id | new_js
-: | :----------------------------------------------------------------------------------------------------------------------
1 | [{"name": "The Cherries", "odds": "2.50"}, {"name": "Draw", "odds": "3.25"}, {"name": "Swansea Jacks", "odds": "2.87"}]
You can use json_table to create rows from the json object.
Just replace table_name with your table name and json with the column that contains json
SELECT json_arrayagg(json_object('name',SUBSTRING_INDEX(person, ':', 1) ,'odds',SUBSTRING_INDEX(person, ':', -1) ))
FROM table_name,
JSON_TABLE(json, '$[*]' COLUMNS (person VARCHAR(40) PATH '$') people;
Here is a Db fiddle you can refer
https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=801de9f067e89a48d45ef9a5bd2d094a
I have JSON data in field hotel_data like this:
{
"title":"foo",
"description":[
{
"locale":"pt",
"content":"pt text"
},
{
"locale":"fr",
"content":"fr text"
}
]
}
I would like to select description only fr description. It is possible using Postgres and how?
I was trying use ->> but it is not working...
SELECT
hotel_data->'description'->>'locale' = 'fr' AS description
FROM hotel LIMIT 1;
Note:
I don't want to use SELECT *...
Excepted output: {description: "fr text"}
You can use a lateral join and json_to_recordset to expand the json array as a set of records. Then, you can filter on column locale in the generated records, and finally recompose a new json object with your expected result:
select json_build_object('description', d.content) hotel_data_descr_fr
from
mytable,
json_to_recordset(hotel_data->'description') as d("locale" text, "content" text)
where d.locale = 'fr'
Demo on DB Fiddle:
with mytable as (
select '{
"title":"foo",
"description":[
{
"locale":"pt",
"content":"pt text"
},
{
"locale":"fr",
"content":"fr text"
}
]
}'::json hotel_data
)
select json_build_object('description', d.content) hotel_data_descr_fr
from
mytable,
json_to_recordset(hotel_data->'description') as d("locale" text, "content" text)
where d.locale = 'fr'
| hotel_data_descr_fr |
| :------------------------- |
| {"description": "fr text"} |
The filtering can be done using the #> operator which can use a GIN index on the hotel_data column. This is typically faster than expanding the array.
select ...
from hotel
where hotel_data #> '{"description": [{"locale":"fr"}] }';
This can also be extended to include more properties:
select ...
from hotel
where hotel_data #> '{"description": [{"locale":"fr", "headline": "nice view'}] }';
But you can only express equality conditions on the key/value pairs with that. Using LIKE is not possible. You will have to expand the array if you want to do that and apply the condition in the WHERE clause - see GMB's answer.
To extract that description, I would use a scalar sub-query:
select (select jsonb_build_object('description', t.descr ->> 'content')
from jsonb_array_elements(h.hotel_data -> 'description') as t(descr)
where t.descr ->> 'locale' = 'fr'
limit 1)
from hotel h
where h.hotel_data #> '{"description": [{"locale":"fr"}] }';
That way you don't need to expand the array for filtering which I expect to be faster if only a few hotels qualify for that condition. But it has the drawback that you need to repeat the condition on the locale in the sub-select.
The limit 1 is only a safety net in case you have more than one french description. If you never have that, it doesn't hurt either
With Postgres 12 this is easier:
select jsonb_build_object(
'description',
jsonb_path_query_first(hotel_data, '$.description ? (#.locale == "fr")') -> 'content'
)
from hotel
where hotel_data #> '{"description": [{"locale":"fr"}] }'
All of the above assumes hotel_data is a jsonb column, if it's not (which it should be) you need to cast it: hotel_data::jsonb
I have a JSONB column called metrics in a table events. It stores various metrics as a flat hash, e.g.
{"m1": 123, "m2": 122.3, "m3": 32}
I would like to extract all the values stored in that column. Is it possible? I have found a function jsonb_object_keys(jsonb), but I failed to find anything similar for values.
Use jsonb_each() for this purpose:
WITH json_test(data) AS ( VALUES
('{"m1": 123, "m2": 122.3, "m3": 32}'::JSONB)
)
SELECT element.value
FROM json_test jt, jsonb_each(jt.data) as element;
Output:
value
-------
123
122.3
32
(3 rows)
Use jsonb_each() in a lateral join:
with val as (
select '{"m1": 123, "m2": 122.3, "m3": 32}'::jsonb js
)
select key, value
from val,
lateral jsonb_each(js);
key | value
-----+-------
m1 | 123
m2 | 122.3
m3 | 32
(3 rows)
Using json_each you can extract the values with:
SELECT value FROM json_each('{"m1": 123, "m2": 122.3, "m3": 32}')
Output
value
-----
123
122.3
32