Question

我正在尝试计算百分比，但编译器一直告诉我它不期望斜杠和第三个选择语句。

Query query = session.createQuery("SELECT 
(SELECT COUNT(*) FROM Reservation r WHERE r.begin BETWEEN :start AND :end) 
/
(SELECT COUNT(*) FROM Reservation res WHERE res.begin BETWEEN :start AND :end AND res.contract IS NOT NULL) * 100");

当我尝试运行它时，它给了我这个错误：

Exception in thread "main" org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected end of subtree

我做错了什么？提前谢谢！

Answer 1

两个计数都可以合并为一个查询：

SELECT (count(r.contract) / count(r)) * 100 
FROM Reservation r 
WHERE r.begin between :start and :end

在一些导致整数除法的数据库中，后续更好：

SELECT (count(r.contract)*1.0 / count(r)) * 100 
FROM Reservation r 
WHERE r.begin between :start and :end

如何进行划分，计算HQL中的百分比？

1 个答案: