how to perform union clause query with hibernate criteria api

问题:

SELECT      supplier_id  FROM suppliers   UNION ALL   SELECT     supplier_id  FROM orders; 

i just creating two criteria above "UNION ALL" clause of query and below "UNION ALL" clause of query.

but my question is how i perform UNION ALL clause in criteria? Thanks in Advance.

回答1:

with criteria I think hibernate does not support UNION ALL but you can use two criteria queries to get the expected result:

Criteria cr1 = session.createCriteria(Suppliers.class);  cr1.setProjection(Projections.projectionList()     .add( Projections.property("supplier_id"), "supplier_id" )  ); List results1 = cr1.list();  Criteria cr2 = session.createCriteria(Orders.class);  cr2.setProjection(Projections.projectionList()     .add( Projections.property("supplier_id"), "supplier_id" )  ); List results2 = cr2.list();  results1.add(results2);   List unionAllList =  results1; //this is the expected result. 

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