Multiple OR clauses - postgresql

Question

I have a list that I'd like to turn onto a where clause using ors:
my_list = [
%{min: 1, max: 10},
%{min: 4, max: 16},
%{min: 5, max: 21}
]
The where clause I'm intended to construct is going to be a part of another, bigger query.
Right now I have to write the following code (note the duplication):
query =
my_list
|> Enum.with_index()
|> Enum.reduce(bigger_query, fn {item, index}, q ->
if index == 0 do
where(q, [table], fragment("? BETWEEN ? AND ?", table.age, ^item["min"], ^item["max"]))
else
or_where(q, [table], fragment("? BETWEEN ? AND ?", table.age, ^item["min"], ^item["max"]))
end
end)
Can this query be rewritten simpler in Ecto terms? If yes, how?
Update. Consider this example:
query = from posts in Post, where: posts.author_id == ^12
query =
my_list
|> Enum.with_index()
|> Enum.reduce(bigger_query, fn {item, index}, q ->
if index == 0 do
where(q, [posts], fragment("? BETWEEN ? AND ?", posts.author_age, ^item["min"], ^item["max"]))
else
or_where(q, [posts], fragment("? BETWEEN ? AND ?", posts.author_age, ^item["min"], ^item["max"]))
end
end)
query = where(q, [posts], posts.published == ^true)
The query is generated correctly:
SELECT * FROM posts WHERE author_id = 12 AND ((age BETWEEN 1 AND 10) OR (age BETWEEN 4 AND 16) AND (age BETWEEN 5 AND 21))
What would be the most compact Ecto code to achieve this?

Answer 1

You don't need to put the first condition in where. or_where works just fine even if there are no where already in the query. The following should work just fine:
query = Enum.reduce(my_list, bigger_query, fn item, q ->
or_where(q, [table], fragment("? BETWEEN ? AND ?", table.age, ^item["min"], ^item["max"]))
end)
You can simplify this further using pattern matching (assuming the keys are strings and you put atoms as keys in the first code snippet in the question by mistake):
query = Enum.reduce(my_list, bigger_query, fn %{"min": min, "max": max}, q ->
or_where(q, [table], fragment("? BETWEEN ? AND ?", table.age, ^min, ^max))
end)