hql查询语句（hibernate）

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1.from子句

from Person

表明从Person持久化类中选出全部的实例。

推荐：from Personas p

2.select子句

select p.name from Person as p

select p.name.firstName from Person as p

select new list(p.name, p.address) fromPerson as p

select new ClassTest(p.name, p.address)from Person as p (有前提)

select p.name as personName from Person asp

select new map(p.name as personName) fromPerson as p (与new map()结合更普遍)

3.统计函数查询:

1: count() 统计记录的条数

2: min() 求最小值

3: max() 求最大值

4: sum() 求和

4: avg() 求平均值

//取得Student的数量

Query query=session.createQuery("select count(*) fromStudent")

//avg()取得Student平均年龄

Query query=session.createQuery("select avg(s.age) from Student ass")

//upper()方法将字符串转为大写

Query query=session.createQuery("select upper(s.name) from Studentas s")

//去除重复行distinct

Query query=session.createQuery("select distinct s.age from Studentas s")

select count(*) from Person

select max(p.age) from Person as p

select p.name || "" || p.addressfrom Person as p

4.多态查询

from Person as p

from java.lang.Object o

from Named as n

5.where子句

from Person where name like"tom%"

from Person as p where p.name like"tom%"

from Cat cat where cat.mate.name like"kit%"

select * from cat_table as table1 cat_table astable2 where table1.mate =

table2.id and table1.name like"kit%"

from Foo foo wherefoo.bar.baz.customer.address.city like "fuzhou%"

from Cat cat, Cat rival where cat.mate =rival.mate

select cat, mate

from Cat cat, Cat mate

where cat.mate = mate

from Cat as cat where cat.id = 123

from Cat as cat where cat.mate.id = 69

from Person as person

where person.id.country = 'AU'

andperson.id.medicareNumber = 123456

from Account as account

where account.owner.id.country = 'AU'

andaccount.owner.id.medicareNumber = 123456

from Cat cat where cat.class = DomesticCat

from Account as a wherea.person.name.firstName like "dd%" // 正确

from Account as a where a.person.name like"dd%" // 错误

6.表达式

=, <>, >, <, >=, <=,between, not between, in, not in, is, like等。

from DomesticCat cat where cat.name between 'A' and 'B'

from DomesticCat cat where cat.name in('Foo', 'Bar', 'Baz')

from DomesticCat cat where cat.name notbetween 'A' and 'B'

from DomesticCat cat where cat.name not in('Foo', 'Bar', 'Baz')

from DomesticCat cat where cat.name is null

from Person as p where p.address is notnull

true 1, false 0

from Cat cat where cat.alive = true

from Cat cat where cat.kittens.size > 0

from Cat cat where size(cat.kittens) > 0

from Calendar cal wheremaxelement(cal.holidays) > current date

from Order order wheremaxindex(order.items) > 100

from Order order whereminelement(order.items) > 10000

//操作集合元素

select mother from Cat as mother, Cat askit

where kit in elements(foo.kittens)

//p的name属性等于集合中某个元素的name属性

select p from NameList list, Person p

where p.name = some elements(list.names)

//操作集合元素

from Cat cat where existselements(cat.kittens)

from Player p where 3 > allelements(p.scores)

from Show show where 'fizard' inindices(show.acts)

//items是有序集合属性，items[0]代表第一个元素

from Order order where order.items[0].id =1234

//holidays是map集合属性，holidays[nationalday]是代表其中第一个元素

select person from Person person, Calendarcalendar

where calendar.holidays['national day'] =person.birthDay

andperson.nationality.calendar = calendar

//下面同时使用list集合和map集合属性

select item from Item item, Order order

whereorder.items[order.deliveredItemIndices[0]] = item and order.id = 11

select item from Item item, Order order

where order.items[maxindex(order.items)] =item and order.id = 11

select item from Item item, Order order

where order.items[size(order.items) - 1] =item

select cust

from Product prod,

Store store

inner join store.customers cust

where prod.name = 'widget'

andstore.location.name in ['Melbourne', 'Sydney']

andprod = all elements(cust.currentOrder.lineItems)

SELECT cust.name, cust.address, cust.phone,cust.id, cust.current_order

FROM customers cust,

stores store,

locations loc,

store_customers sc,

product prod

WHERE prod.name = 'widget'

ANDstore.loc_id = loc.id

ANDloc.name IN ('Melbourne', 'Sydney')

ANDsc.store_id = store.id

ANDsc.cust_id = cust.id

ANDprod.id = ALL(

SELECT item.prod_id

FROMline_items item, orders o

WHERE item.order_id = o.id

ANDcust.current_order = o.id

)

like语句：

String hql = "from Users u where u.userName=? and u.userPass=? andu.userInfo like ?";

Object param[] = { userName, password, '%'+info+'%' };

7.order by子句

from Person as p

order by p.name, p.age

from Person as p

order by p.name asc, p.age desc

8.group by子句

select cat.color, sum(cat.weight),count(cat)

from Cat cat

group by cat.color

//select后出现的id处出现在group by之后，而name属性则出现在聚集函数中

select foo.id, avg(name), max(name)

from Foo foo join foo.names name

group by foo.id

select cat.color, sum(cat.weight),count(cat)

from Cat cat

group by cat.color

having cat.color in (eg.Color.TABBY,eg.Color.BLACK)

select cat

from Cat cat

join cat.kittens kitten

group by cat

having avg(kitten.weight) > 100

order by count(kitten) asc,sum(kitten.weight) desc

9.子查询:

all 表示所有记录

any 便是所有记录中的任意一条

somy 与any用法一样

in 等价于any

exists 表示子查询至少要返回一条数据

all:

from Team t where 22<all(select s.age from Student s)

from Team t where all(select s.age from t.student s)>22

from Cat as fatcat

where fatcat.weight > (selectavg(cat.weight) from DomesticCat cat)

from Cat as cat

where not (cat.name, cat.color) in (

select cat.name, cat.color from DomesticCatcat

)

10.fetch关键字

from Person as p join p.scores

from Document fetch all properties order byname

from Document doc fetch all propertieswhere lower(doc.name) like '%cat%'

11.查询链接:

与SQL查询一样,hql也支持连接查询,如内连接,外连接和交叉连接.支持的链接类型是从ANSISQL中借鉴来的.

1: inner jion (内连接)

2: left outer join (左外连接)

3: right outer join(右外连接)

4: full join(全连接--不常用)

inner jion 可以简写为join.

正常情况下必须要建关联。