I have following jsonb column which name is data in my sql table.
{
"special_note": "Some very long special note",
"extension_conditions": [
{
"condition_id": "5bfb8b8d-3a34-4cc3-9152-14139953aedb",
"condition_type": "OPTION_ONE"
},
{
"condition_id": "fbb60052-806b-4ae0-88ca-4b1a7d8ccd97",
"condition_type": "OPTION_TWO"
}
],
"floor_drawings_file": "137c3ec3-f078-44bb-996e-161da8e20f2b",
}
What I need to do is to update every object's field with name condition_type in extension_conditions array field from OPTION_ONE to MARKET_PRICE and OPTION_TWO leave the same.
Consider that this extension_conditions array field is optional so I need to filter rows where extension_conditions is null
I need a query which will update all my jsonb columns of rows of this table by rules described above.
Thanks in advance!
You can use such a statement containing JSONB_SET() function after determining the position(index) of the related key within the array
WITH j AS
(
SELECT ('{extension_conditions,'||idx-1||',condition_type}')::TEXT[] AS path, j
FROM tab
CROSS JOIN JSONB_ARRAY_ELEMENTS(data->'extension_conditions')
WITH ORDINALITY arr(j,idx)
WHERE j->>'condition_type'='OPTION_ONE'
)
UPDATE tab
SET data = JSONB_SET(data,j.path,'"MARKET_PRICE"',false)
FROM j
Demo 1
Update : In order to update for multiple elements within the array, the following query containing nested JSONB_SET() might be preferred to use
UPDATE tab
SET data =
(
SELECT JSONB_SET(data,'{extension_conditions}',
JSONB_AGG(CASE WHEN j->>'condition_type' = 'OPTION_ONE'
THEN JSONB_SET(j, '{condition_type}', '"MARKET_PRICE"')
ELSE j
END))
FROM JSONB_ARRAY_ELEMENTS(data->'extension_conditions') AS j
)
WHERE data #> '{"extension_conditions": [{"condition_type": "OPTION_ONE"}]}';
Demo 2
Related
Assume i have a table called MyTable and this table have a JSON type column called myjson and this column have next value as a json array hold multiple objects, for example like next:
[
{
"budgetType": "CF",
"financeNumber": 1236547,
"budget": 1000000
},
{
"budgetType": "ENVELOPE",
"financeNumber": 1236888,
"budget": 2000000
}
]
So how i can search if the record has any JSON objects inside its JSON array with financeNumber=1236547
Something like this:
SELECT
t.*
FROM
"MyTable",
LATERAL json_to_recordset(myjson) AS t ("budgetType" varchar,
"financeNumber" int,
budget varchar)
WHERE
"financeNumber" = 1236547;
Obviously not tested on your data, but it should provide a starting point.
with a as(
SELECT json_array_elements(myjson)->'financeNumber' as col FROM mytable)
select exists(select from a where col::text = '1236547'::text );
https://www.postgresql.org/docs/current/functions-json.html
json_array_elements return setof json, so you need cast.
Check if a row exists: Fastest check if row exists in PostgreSQL
I am attempting to update a jsonb column pagesRead on table Books which contains an array of objects. The structure of it looks similar to this:
[{
"book": "Moby Dick",
"pagesRead": [
"1",
"2",
"3",
"4"
]
},
{
"book": "Book Thief",
"pagesRead": [
"1",
"2"
]
}]
What I am trying to do is update the pagesRead when a specific page of the book is read or if someone has started a new book, add an extra entry into it.
I am able to retrieve the specific book details, but I am unsure about how to update it.
EDIT: So I had to use the Update query from S-Man to add a book entry, but I used the Insert query from Barbaros Özhan to handle updating the page
Some thoughts before:
You should never store structured data as it is in one column. This yields problems with updates, indexing (so, searching/performance), filtering, everything. Please normalize everything into proper tables and columns
You should never store arrays. Normalize it.
Do not use type text to store integer (pages)
"pagesRead" is a sibling of your filter element ("book"). This makes it much more complicated to reference it than referencing it as a child. So think about the book name (or better: an id) as key like {"my_id_for_book_thief": {"name" : "Book Thief", "pagesRead": [...]}}. In that case, you could use a path for referencing it. Otherwise, we need to extract the array, have a look into each book attribute and reference its sibling
demo:db<>fiddle
Adding a book is quite simple (Assuming that you are using type jsonb instead of type json):
SELECT mydata || '{"book": "Lord Of The Rings", "pagesRead": []}'
FROM mytable
Update:
UPDATE mytable
SET mycolumn = mycolumn || '{"book": "Lord Of The Rings", "pagesRead": []}'
Adding a pagesRead value:
SELECT
jsonb_agg( -- 4
jsonb_build_object( -- 3
'book', elem -> 'book',
'pagesRead', CASE WHEN elem ->> 'book' = 'Moby Dick' THEN -- 2
elem -> 'pagesRead' || '"42"'
ELSE elem -> 'pagesRead' END
)
) as new_array
FROM mytable,
jsonb_array_elements(mydata) as elem -- 1
Extract the array into one record per element
Add a page if element contains correct book
Rebuild the object
Reaggregate your array.
Update would be:
UPDATE mytable
SET mycolumn = s.new_array
FROM (
-- <query above>
) s
Assuming you want to add a new page for the second book (Book Thief), then using JSONB_INSERT() function with the following Update Statement will be enough
UPDATE books
SET pagesRead = JSONB_INSERT(pagesRead,'{1,pagesRead,1}','"3"'::JSONB,true)
But, in order to make it a dynamical solution, without knowing the position of the book within the main array, and adding the new page number to the end of the pagesRead array of the desired book, determine the position, and the related array's length within the subquery as
WITH b AS
(
SELECT idx-1 AS pos1,
JSONB_ARRAY_LENGTH( (j ->> 'pagesRead')::JSONB )-1 AS pos2
FROM books
CROSS JOIN JSONB_ARRAY_ELEMENTS(pagesRead)
WITH ORDINALITY arr(j,idx)
WHERE j ->> 'book' = 'Book Thief'
)
UPDATE books
SET pagesRead =
JSONB_INSERT(
pagesRead,
('{'||pos1||',pagesRead,'||pos2||'}')::TEXT[],
--# pos1 stands for the position within the main array
--# pos2 stands for the position within the related pagesRead array
'"3"'::JSONB, --# an arbitrary page number
true --# the new page value will be inserted after the target path
)
FROM b
Demo
I have a table mytable and a JSONB column employees that contains data like this:
[ {
"name":"Raj",
"email":"raj#gmail.com",
"age":32
},
{
"name":"Mohan",
"email":"Mohan#yahoo.com",
"age":21
}
]
I would like to extract only the names and save them in a list format, so the resulting cell would look like this:
['Raj','Mohan']
I have tried
select l1.obj ->> 'name' names
from mytable t
cross join jsonb_array_elements(t.employees) as l1(obj)
but this only returns the name of the first array element.
How do I get the name of all array elements?
Thanks!
PostgreSQL 11.8
In Postgres 12, you can use jsonb_path_query_array():
select jsonb_path_query_array(employees, '$[*].name') as names
from mytable
In earlier versions you need to unnest then aggregate back:
select (select jsonb_agg(e -> 'name')
from jsonb_array_elements(employees) as t(e)) as names
from mytable
Test data
DROP TABLE t;
CREATE TABLE t(_id serial PRIMARY KEY, data jsonb);
INSERT INTO t(data) VALUES
('{"a":1,"b":2, "c":3}')
, ('{"a":11,"b":12, "c":13}')
, ('{"a":21,"b":22, "c":23}')
Problem statement: I want to receive an arbitrary JSONB parameter which acts as a filter on column t.data, such as
{ "b":{ "from":0, "to":20 }, "c":13 }
and use this to select matching rows from my test table t.
In this example, I want rows where b is between 0 and 20 and c = 13.
No error is required if the filter specifies a "column" (or "tag") which does not exist in t.data - it just fails to find a match.
I've used numeric values for simplicity but would like an approach which generalises to text as well.
What I have tried so far. I looked at the containment approach, which works for equality conditions, but am stumped on a generic way of handling range conditions:
select * from t
where t.data#> '{"c":13}'::jsonb;
Background: This problem arose when building a generic table-preview page on a website (for Admin users).
The page displays a filter based on various columns in whichever table is selected for preview.
The filter is then passed to a function in Postgres DB which applies this dynamic filter condition to the table.
It returns a jsonb array of the rows matching the filter specified by the user.
This jsonb array is then used to populate the Preview resultset.
The columns which make up the filter may change.
My Postgres version is 9.6 - thanks.
if you want to parse { "b":{ "from":0, "to":20 }, "c":13 } you need a parser. It is out of scope of json functions, but you can write "generic" query using AND and OR to filter by such json, eg:
https://www.db-fiddle.com/f/jAPBQggG3p7CxqbKLMbPKw/0
with filt(f) as (values('{ "b":{ "from":0, "to":20 }, "c":13 }'::json))
select *
from t
join filt on
(f->'b'->>'from')::int < (data->>'b')::int
and
(f->'b'->>'to')::int > (data->>'b')::int
and
(data->>'c')::int = (f->>'c')::int
;
Thanks for the comments/suggestions.
I will definitely look at GraphQL when I have more time - I'm working under a tight deadline at the moment.
It seems the consensus is that a fully generic solution is not achievable without a parser.
However, I got a workable first draft - it's far from ideal but we can work with it. Any comments/improvements are welcome ...
Test data (expanded to include dates & text fields)
DROP TABLE t;
CREATE TABLE t(_id serial PRIMARY KEY, data jsonb);
INSERT INTO t(data) VALUES
('{"a":1,"b":2, "c":3, "d":"2018-03-10", "e":"2018-03-10", "f":"Blah blah" }')
, ('{"a":11,"b":12, "c":13, "d":"2018-03-14", "e":"2018-03-14", "f":"Howzat!"}')
, ('{"a":21,"b":22, "c":23, "d":"2018-03-14", "e":"2018-03-14", "f":"Blah blah"}')
First draft of code to apply a jsonb filter dynamically, but with restrictions on what syntax is supported.
Also, it just fails silently if the syntax supplied does not match what it expects.
Timestamp handling a bit kludgey, too.
-- Handle timestamp & text types as well as int
-- See is_timestamp(text) function at bottom
with cte as (
select t.data, f.filt, fk.key
from t
, ( values ('{ "a":11, "b":{ "from":0, "to":20 }, "c":13, "d":"2018-03-14", "e":{ "from":"2018-03-11", "to": "2018-03-14" }, "f":"Howzat!" }'::jsonb ) ) as f(filt) -- equiv to cross join
, lateral (select * from jsonb_each(f.filt)) as fk
)
select data, filt --, key, jsonb_typeof(filt->key), jsonb_typeof(filt->key->'from'), is_timestamp((filt->key)::text), is_timestamp((filt->key->'from')::text)
from cte
where
case when (filt->key->>'from') is null then
case jsonb_typeof(filt->key)
when 'number' then (data->>key)::numeric = (filt->>key)::numeric
when 'string' then
case is_timestamp( (filt->key)::text )
when true then (data->>key)::timestamp = (filt->>key)::timestamp
else (data->>key)::text = (filt->>key)::text
end
when 'boolean' then (data->>key)::boolean = (filt->>key)::boolean
else false
end
else
case jsonb_typeof(filt->key->'from')
when 'number' then (data->>key)::numeric between (filt->key->>'from')::numeric and (filt->key->>'to')::numeric
when 'string' then
case is_timestamp( (filt->key->'from')::text )
when true then (data->>key)::timestamp between (filt->key->>'from')::timestamp and (filt->key->>'to')::timestamp
else (data->>key)::text between (filt->key->>'from')::text and (filt->key->>'to')::text
end
when 'boolean' then false
else false
end
end
group by data, filt
having count(*) = ( select count(distinct key) from cte ) -- must match on all filter elements
;
create or replace function is_timestamp(s text) returns boolean as $$
begin
perform s::timestamp;
return true;
exception when others then
return false;
end;
$$ strict language plpgsql immutable;
I have a json column titled 'classifiers' with data like this:
[ { "category": "Building & Trades", "type": "Services"
, "subcategory": "Construction" } ]
I would like to pull each element and insert into columns on the same row titled, for example, 'category', 'type' and 'subcategory'.
This query pulls out what I want, in this case 'category':
SELECT parts->'category' AS category
FROM (SELECT json_array_elements(classifiers) AS parts FROM <tablename>) AS more_parts
I can't figure out the 'WHERE' part in an UPDATE/SET/WHERE type of query, for example:
UPDATE <table>
SET category = (SELECT parts->'category' AS category
FROM (SELECT json_array_elements(classifiers) AS parts
FROM <tablename>
) AS more_parts
) WHERE ???
Without WHERE multiple rows are returned.
I would like to pull each element and insert into columns on the same
row titled, for example, 'category', 'type' and 'subcategory'.
Sounds like you really want this:
UPDATE tbl
SET category = classifiers->0->'category'
,type = classifiers->0->'type'
,subcategory = classifiers->0->'subcategory'
Updates all rows. Requires Postgres 9.3+.
The first operator ->0 reverences the only object in the array (json array index starting from 0 unlike Postgres arrays, which start from 1 per default).
The second operator ->'category' gets the field from the object.
Refer to the manual here.