Question

我想通过案例陈述订购，是否可能？我该怎么办？

SELECT new com.systemname.to.UserDataHolder(u.userId, 
CASE  WHEN (u.place.cityId = :cityId) THEN 1  WHEN (u.place.stateId = :stateId) THEN 2  ELSE 3 END)  
FROM User u 
ORDER BY u.userId DESC

Answer 1

您使用的是哪个JPA提供商？

尝试，

SELECT u.userId, 
(CASE  
    WHEN (u.place.cityId = :cityId) THEN 1
    WHEN (u.place.stateId = :stateId) THEN 2
    ELSE 3 END) as myNum
FROM User u 
ORDER BY u.userId, myNum DESC

，或者

SELECT new com.systemname.to.UserDataHolder(u.userId, 
CASE  
    WHEN (u.place.cityId = :cityId) THEN 1
    WHEN (u.place.stateId = :stateId) THEN 2
    ELSE 3 END)
FROM User u 
ORDER BY u.userId, CASE  
    WHEN (u.place.cityId = :cityId) THEN 1
    WHEN (u.place.stateId = :stateId) THEN 2
    ELSE 3 END DESC

Answer 2

目前无法测试，所以我不确定这是否是有效的语法，但是你可以添加一个“AS”吗？

SELECT new com.systemname.to.UserDataHolder(u.userId, 
CASE  
    WHEN (u.place.cityId = :cityId) THEN 1
    WHEN (u.place.stateId = :stateId) THEN 2
    ELSE 3 END as myNum)
FROM User u 
ORDER BY u.userId, myNum DESC

在JPA中按“CASE列”排序

2 个答案: