java - 将查询从 sql 转换为 hql

Question

我想将此查询转换为 HQL

select status,count(*) from server s, status st where s.id = st.server_id and st.created = (select max(ss.created) from status ss where ss.server_id = s.id) group by st.status 

我试过了

@Query("select new StatisticServerDTO( st.status, count(*)) from Server s, Status st where "
            + "s.id = st.server.id and st.created = (select max(ss.created) from Status ss where ss.server.id = s.id)"
            + "group by st.status")
    List<StatisticServerDTO> nbrServerByStatus();

但它不起作用

我的返回类是这样的:

public class StatisticServerDTO{

    private String status;
    private int nbr;

   ...
}

异常(exception)情况是:

Caused by: java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.MethodNode 
 \-[METHOD_CALL] MethodNode: '('
    +-[METHOD_NAME] IdentNode: 'StatisticServerDTO' {originalText=StatisticServerDTO}
    \-[EXPR_LIST] SqlNode: 'exprList'
       +-[DOT] DotNode: 'status1_.status' {propertyName=status,dereferenceType=PRIMITIVE,getPropertyPath=status,path=st.status,tableAlias=status1_,className=com.example.beans.Status,classAlias=st}
       |  +-[ALIAS_REF] IdentNode: 'status1_.id' {alias=st, className=com.example.beans.Status, tableAlias=status1_}
       |  \-[IDENT] IdentNode: 'status' {originalText=status}
       \-[COUNT] CountNode: 'count'
          \-[ROW_STAR] SqlNode: '*'

Answer 1

您的查询中缺少 New

@Query("select NEW StatisticServerDTO( st.status, count(*)) from Server s, Status st where " + "s.id = st.server.id and st.created = (select max(ss.created) from Status ss where ss.server.id = s.id)" + "按 st.status 分组") 列出 nbrServerByStatus();