Now there are two classes, for example Parent and Child, as we all know one parent maybe has many children.
Parent
－id (attribute)
－name (attribute)
Child
－id (attribute)
－name (attribute)
－parentID (attribute)
－age (attribute)

If I know the information about name and parentID of a child, how to query the age information about this child?

1. acording to relation of Parent and Child, firstly load Parent with parentID, secondly get all children of this parent, finally use child's name to get the child instance.

2. Hibernate provides a "createSQLQuery" funcation in Query class, but the sql format in the function is not same as the sql used in database client.

any idea else?
thanks in advance.

Why you need to query the Parent to get a child attribute?
just query the Child -))

"Select child.age from Child child where child.parentID =....