java - 如何有效编写 JPA 命名查询

Question

我已命名查询，如下所示:

@NamedQueries({
    @NamedQuery(name = "table.getvalues", query = "select p from table p where p.a = :a and p.b = :b and p.c = :c order by id"),
    @NamedQuery(name = "table.getvalueswhencisnull", query = "select p from table p where p.a = :a and p.b = :b and p.c is null order by id")
})

两个命名查询之间的唯一区别是 c,c 的值可以为 null，并且 sql 查询的语法仅因此而不同。

有没有办法可以有效地将这两个语句结合起来？

Answer 1

使用这个:

select p from table p where p.a = :a and p.b = :b and (p.c is null or p.c=:c) order by id