Select Parent Record With All Children in SQL

Question

Let\'s say I have two tables, \"Parent\" and \"Child\". Parent-to-Child is a many:many relationship, implemented through a standard cross-referencing table.

I want to fi

Answer 1

( I guess where you said "Child Eve references Eve" you meant "Child Eve references Bob", right?)

I think I've got it... looks ugly... the secret is the double negation... that is, everyone for which it's true,, is the same as not anyone for which is false... (ok, I have troubles with my english, but I guess you understand what I mean)

select * from parent

parent_id                               name
--------------------------------------- --------------------------------------------------
1                                       alice
2                                       bob

select * from child

child_id                                name
--------------------------------------- --------------------------------------------------
1                                       charlie
2                                       david
3                                       eve

select * from parent_child

parent_id                               child_id
--------------------------------------- ---------------------------------------
1                                       1
2                                       1
1                                       2
2                                       3

select * from parent p 
where not exists(
    select * from child c 
    where
        c.child_id in ( 1, 2, 3 ) and 
        not exists(
            select * from parent_child pc where
                pc.child_id = c.child_id and
                pc.parent_id = p.parent_id
        )
)

--when child list = ( 1 )
parent_id                               name
--------------------------------------- --------------------------------------------------
1                                       alice
2                                       bob

--when child list = ( 1, 2 )
parent_id                               name
--------------------------------------- --------------------------------------------------
1                                       alice

--when child list = ( 1, 2, 3 )
parent_id                               name
--------------------------------------- --------------------------------------------------

well, I hope it helps...