Reputation: 2619
I am attempting to remove an element from my database. The element I want to remove is within a JSON object called playerContainer which contains an array named players. This all sits within a table called site_content. I am trying to remove the object based on it's ID, however I get this error.
DELETE elem from site_content, lateral jsonb_array_elements(content->'playersContainer'->'players') elem where elem @> '{"id":"22"}'
because: ERROR: syntax error at or near "elem" Position: 27
Below is my query, can anyone see where I am going wrong?
DELETE elem
from site_content,
lateral jsonb_array_elements(content->'playersContainer'->'players') elem
where elem @> '{"id":"1"}'
Here is the sample JSON
"playersContainer": {
"players": [
{
"id": "1",
"name": "Nick",
"teamName": "Shire Soldiers",
"ratings": [
1,
5,
6,
9
],
"assists": 17,
"manOfTheMatches": 20,
"cleanSheets": 1,
"data": [
3,
2,
3,
5,
6
],
"totalGoals": 19
},
}
Upvotes: 1
Views: 4230
Reputation: 2349
DELETE works on rows of a table. Therefore you can't use it unless if you want to remove the complete row.
Try this:
create temp table testing as
select
'{ "playersContainer": {
"players": [
{
"id": "1",
"name": "Nick"
},
{
"id": "2",
"name": "Rick"
},
{
"id": "3",
"name": "Trick"
}
]
}}'::jsonb as value;
Now you need to find the position of the player you want to remove, lets say you want Rick with id 2 (minus 1 because index starts from 0)
select position-1 from testing, jsonb_array_elements(value->'playersContainer'->'players') with ordinality arr(elem, position) WHERE elem->>'id' = '2';
Now you can combine this with an UPDATE
statement to update the field. Use minus (-) operator to remove the element at wanted index.
UPDATE testing SET value = jsonb_set(value, '{playersContainer,players}', (value->'playersContainer'->'players') - (select position-1 from testing, jsonb_array_elements(value->'playersContainer'->'players') with ordinality arr(elem, position) WHERE elem->>'id' = '2')::int );
End result:
{
"playersContainer":{
"players":[
{
"id":"1",
"name":"Nick"
},
{
"id":"3",
"name":"Trick"
}
]
}
}
Upvotes: 4