1：对比原生sql查询和 hql查询 返回结果的类型
count:
sql: select count(0) from xxx where .... 返回 BigInteger
hql: select count(0) from xxx where .... 返回 Long
max:
sql: select max(0) from xxx where .... 返回 BigDecimal
hsql :select max(0) from xxx where ...返回 deciaml
concat:
sql：select concat('select','xxx') from xxx where ...返回 byte[](很恶心)
hql: 没有这个运算。