如何使用hibernate标准API执行联合子句查询 [英] how to perform union clause query with hibernate criteria api

问题描述

SELECT 
    supplier_id  FROM suppliers   UNION ALL 

SELECT     supplier_id  FROM orders;

我在查询的UNION ALL子句上面创建了两个条件，并在UNION ALL查询。

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

但我的问题是我如何在条件中执行UNION ALL子句？
感谢提前。

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

推荐答案

标准我认为hibernate不支持 UNION ALL 但您可以使用两个条件查询来获得预期结果：

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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