java如何使本机查询忽略筛选器的空白值？

Question

我有一个带有几个过滤器的本机查询

当2020为显示“2020”的值时

当2021为值时，表示“2021”，

当值不为2020, 2021时，或''（空白值）显示“NoWurn”，

该值为空时，显示“未知”

此查询的问题是notCurrent筛选器中显示了空/null/''值

如何确保这些空白/空值仅显示在“未知”筛选器中，而不显示在notCurrent筛选器中。这个查询有什么问题

@Query(nativeQuery = true, value = "SELECT " +
            "COUNT(DISTINCT pd.id) FILTER (WHERE c.year = '2020') AS \"2020\",  " +
            "COUNT(DISTINCT pd.id) FILTER (WHERE c.year = '2021') AS \"2021\",  " +
            "COUNT(DISTINCT pd.id) FILTER (WHERE c.year NOT IN ('2020', '2021', '')) AS \"notCurrent\",  " +
            "COUNT(pd.id) FILTER (WHERE c.year = '') AS \"unknown\" " +