Query builder supports one-to-many relationships, but it does not visually display them in builder. It only draws a line with no other markings that show direction of one-to-many, or that it is other than 1:1.
Should extend display from Relationships display -- adding identifiers would be more apt here anyway. Left join should be 1:[infinity]; inner join 1:1, etc.
It doesen't work yet in all LO-versions. It's an ask for an enhancement.
So I will switch this to "New" and "Inherited From OOo".
Could be a good Idea to show the differences of "Left Join", "Join" etc.
Adding self to CC if not already on