Dynamic CASE WHEN in Postgresql - sql

Question

I have a list of Conversations, that come from multiple pages as below:
[
{
"id": 1,
"page_id": 1,
"name": "name 1",
"assigned_user_ids": ["user1"]
},
{
"id": 2,
"page_id": 2,
"name": "name 2",
"assigned_user_ids": ["user2"]
},
{
"id": 3,
"page_id": 1,
"name": "name 3",
"assigned_user_ids": ["user2"]
},
{
"id": 4,
"page_id": 2,
"name": "name 4",
"assigned_user_ids": ["user1"]
}
]
Imagine that "User 1" is calling the query, and User 1 can get all items of page_id = 1 (because user 1 is administrator), but in page_id = 2 he/she
only get the items that has been assigned to, in this case is item with id = 4.
So when user 1 query, what I want to received is:
[
{
"id": 1,
"page_id": 1,
"name": "name 1",
"assigned_user_ids": ["user1"]
},
{
"id": 3,
"page_id": 1,
"name": "name 3",
"assigned_user_ids": ["user2"]
},
{
"id": 4,
"page_id": 2,
"name": "name 4",
"assigned_user_ids": ["user1"]
}
]
This is my existing query in SQL look like:
SELECT * FROM Conversations
WHERE PageId IN (1, 2)
Can any one tell me how to modify my SQL to resolve my problem?
Thank you very much!

Answer 1

You can use OR It will either give you what is on page one, so everything from there, or everything that has been assigned to userId 1. So effectively only the things that have been assigned on every other page.
SELECT * FROM Conversations
WHERE PageId = 1 OR userId = 1
If you want to restrict this to only some pages, you can still use IN.
SELECT * FROM Conversations
WHERE PageId = 1 OR userId = 1 AND pageId IN (2,3,4)