HQL其中IN为空列表崩溃

Question

我有一个像这样的HQL语句:

Select cast(ed.employee.employeeID as int) AS emp_id FROM Education AS ed WHERE ed.type.name IN (:typeNames)

但有时,typeNames为空.这会导致以下情况:

org.hibernate.hql.ast.QuerySyntaxException: unexpected end of subtree [Select cast(ed.employee.employeeID as int) AS emp_id FROM Education AS ed WHERE ed.type.name IN ()]

接受空列表的解决方案是什么？

Answer 1

如果typeNames为空/ null,我可能不会执行查询:

if (typeNames) result = Foo.executeQuery("select ... where e.type.name in :typeNames", [typeNames: typeNames)

Answer 2

我使用的一种解决方案是将一些虚拟值与您的输入一起放在列表中，以确保它永远不会为空。当然，只有在可以选择虚拟值的情况下才能这样做。

如果您的输入列表是typeNamesOrig：

List<String> typeNames = new ArrayList<String>(typeNamesOrig);
typeNames.add("valueThatDoesNotExistForSure");
query.setParameterList("typeNames",typeNames);