在WHERE子句中使用CASE WHEN进行JPA查询.怎么做？

Question

如何使用JPA运行如下所示的查询.(它适用于纯SQL)

SELECT t
FROM table t
WHERE
  (
    CASE WHEN (( ... subquery ... )  IS NULL)
    THEN (t.category IS NULL)
    ELSE (t.viewId = :viewId)
    END
  )

我得到了MismatchedTokenException在IS

THEN (t.category IS NULL)

可能吗？或者我需要重写这个查询？

Answer 1

您可以将where子句转换为:

where
    ((... my first condition ...) and (something is NULL))
    or
    (not (... first condition ...) and (something2 = otherthing))