Hibernate(HQL) 怪异的count()函数

近日发现HQL中， count()函数要求还比较严格，举例说：


1、count(1)报错

<query name="getRecordCountById">
	select count(1) as recordCount from Km c
	where c.id=:id
</query>

2、count(c.*)报错

<query name="getRecordCountById">
	select count(c.*) as recordCount from Km c
	where c.id=:id
</query>

3、count(*)正确

<query name="getRecordCountById">
	select count(*) as recordCount from Km c
	where c.id=:id
</query>