How to delete a node from a JSONB Array across all table rows in Postges? - postgresql

Question

I have a table called "Bookmarks" that contains several standard rows and also a JSONB column called "columnsettings"
The content of this JSONB column looks like this.
[
{
"data": "id",
"width": 25
},
{
"data": "field_1",
"width": 125
},
{
"data": "field_12",
"width": 125
},
{
"data": "field_11",
"width": 125
},
{
"data": "field_2",
"width": 125
},
{
"data": "field_7",
"width": 125
},
{
"data": "field_8",
"width": 125
},
{
"data": "field_9",
"width": 125
},
{
"data": "field_10",
"width": 125
}
]
I am trying to write an update statement which would update this columnsettings by removing a specific node I specify. For example, I might want to update the columnsettings and remove just the node where data='field_2' as an example.
I have tried a number of things...I believe it will look something like this, but this is wrong.
update public."Bookmarks"
set columnsettings =
jsonb_set(columnsettings, (columnsettings->'data') - 'field_2');
What is the correct syntax to remove a node within a JSONB Array like this?
I did get a version working when there is a single row. This correctly updates the JSONB column and removes the node
UPDATE public."Bookmarks" SET columnsettings = columnsettings - (select position-1 from public."Bookmarks", jsonb_array_elements(columnsettings) with ordinality arr(elem, position) WHERE elem->>'data' = 'field_2')::int
However, I want it to apply to every row in the table. When there is more than 1 row, I get the error " more than one row returned by a subquery used as an expression"
How do I get this query to update all rows in the table?
UPDATED, the answer provided solved my issue.
I now have another JSONB column where I need to do the same filtering. The structure is a bit different, it looks likke this
{
"filters": [
{
"field": "field_8",
"value": [
1
],
"header": "Colors",
"uitype": 7,
"operator": "searchvalues",
"textvalues": [
"Red"
],
"displayfield": "field_8_options"
}
],
"rowHeight": 1,
"detailViewWidth": 1059
}
I tried using the syntax the same way as follows:
UPDATE public."Bookmarks"
SET tabsettings = filtered_elements.tabsettings
FROM (
SELECT bookmarkid, JSONB_AGG(el) as tabsettings
FROM public."Bookmarks",
JSONB_ARRAY_ELEMENTS(tabsettings) AS el
WHERE el->'filters'->>'field' != 'field_8'
GROUP BY bookmarkid
) AS filtered_elements
WHERE filtered_elements.bookmarkid = public."Bookmarks".bookmarkid;
This gives an error: "cannot extract elements from an object"
I thought I had the syntax correct, but how should this line be formatted?
WHERE el->'filters'->>'field' != 'field_8'
I tried this format as well to get to the array. This doesn't given an error, but it doesn't find any matches...even though there are records.
UPDATE public."Bookmarks"
SET tabsettings = filtered_elements.tabsettings
FROM (
SELECT bookmarkid, JSONB_AGG(el) as tabsettings
FROM public."Bookmarks",
JSONB_ARRAY_ELEMENTS(tabsettings->'filters') AS el
WHERE el->>'field' != 'field_8'
GROUP BY bookmarkid
) AS filtered_elements
WHERE filtered_elements.bookmarkid = public."Bookmarks".bookmarkid;
UPDATED .
This query now seems to work if there is more than one "filter" in the array.
However, if there is only 1 element in array which should be excluded, it doesn't remove the item.
UPDATE public."Bookmarks"
SET tabsettings = filtered_elements.tabsettings
FROM (
SELECT bookmarkid,
tabsettings || JSONB_BUILD_OBJECT('filters', JSONB_AGG(el)) as tabsettings
FROM public."Bookmarks",
-- this must be an array
JSONB_ARRAY_ELEMENTS(tabsettings->'filters') AS el
WHERE el->>'field' != 'field_8'
GROUP BY bookmarkid
) AS filtered_elements
WHERE filtered_elements.bookmarkid = public."Bookmarks".bookmarkid;

Answer 1

You can deconstruct, filter, and re-construct the JSONB array. Something like this should work:
UPDATE bookmarks
SET columnsettings = filtered_elements.columnsettings
FROM (
SELECT id, JSONB_AGG(el) as columnsettings
FROM bookmarks,
JSONB_ARRAY_ELEMENTS(columnsettings) AS el
WHERE el->>'data' != 'field_2'
GROUP BY id
) AS filtered_elements
WHERE filtered_elements.id = bookmarks.id;
Using JSONB_ARRAY_ELEMENTS, you transform the JSONB array into rows, one per object, which you call el. Then you can access the data attribute to filter out the "field_2" entry. Finally, you group by id to put the remainign values back together, and update the corresponding row.
EDIT If your data is a nested array in an object, override the object on the specific key:
UPDATE bookmarks
SET tabsettings = filtered_elements.tabsettings
FROM (
SELECT id,
tabsettings || JSONB_BUILD_OBJECT('filters', JSONB_AGG(el)) as tabsettings
FROM bookmarks,
-- this must be an array
JSONB_ARRAY_ELEMENTS(tabsettings->'filters') AS el
WHERE el->>'field' != 'field_2'
GROUP BY id
) AS filtered_elements
WHERE filtered_elements.id = bookmarks.id;