How do I insert multiple values into a single column using sqlite?

Question

I would like to have a column in my table that can store a variable amount of int values. What is the best way to do this? I would like to be able to select based on these ints so a csv list would not work.

Basically I have a bunch of rows in my table that can belong to multiple different categories. I would like to store the category ids in my table and be able to select rows based on the categories they belong to. I believe this is called a many to many relationship. I am using sqlite.

Answer 1

You will need an intermediary table, where each row is a item and a category.

ItemID          Category
111             1
111             2
222             1
222             2
222             3
333             3

To select all items based on a category (say category 2), you could do the following query

SELECT * FROM Items AS I INNER JOIN ItemsInCategories AS N ON N.ItemID = I.ItemID WHERE N.Category = 2

And this would return

ItemID
111
222

Answer 2

A many to many relationship should be accomplished using a mapping table. Not by hacking a multi-valued column type

For example this BlogPost <-> Category sample:

Blog
  Id
  Title
  Content

Category
  Id
  Title

Blog_Category
  BlogId
  CategoryId

This means that when BlogPost with Id 12, is part of Category 3,5 and 10, Blog_Category contains these rows:

12, 3
12, 5
12, 10