SQL query between 2 tables linked by many to many relationship

[Luis234]

I have a parent class with a first name, last name, and a collection of "children". Put the child class that is just a name.

The two classes are connected by a link "many to many" (1 .. n).

I run a query: "give me all those who have children named John and Mary." So I will have all the result of people who have at least two children, a John and Mary. Logically it is correct.

Is it too complex?

[Modifier]

According to me, the SQL query should look like this:

  SELECT * 
  FROM Parent AS x
  WHERE EXISTS (SELECT * 
                FROM (SELECT y.Parentid  
                        FROM Child AS y INNER JOIN Child AS z 
                                      ON y.ParentId = z.ParentId 
                        WHERE y.FirstName = 'John' AND z.FirstName = 'Mary') AS t 
                WHERE x.Parentid = t.Parentid) 
  ;

[Lemog]

Inappropriate because your statement is false in the database:

The two classes are connected by a link "many to many" (1 .. n).

1 .. n means link 1 to many.
many-to-many means many to many

So the two concepts are altogether different.