我是新来的JPQL和挣扎了一下翻译我的SQL来JPQL。我有一个简单的查询,这在MySQL的工作原理:MySQL来JPQL内加入
SELECT askorder.price, bidorder.price from OrderBook JOIN askorder
ON OrderBook.ASKORDERID_ORDERID = askorder.ORDERID
JOIN bidorder ON OrderBook.BIDORDERID_ORDERID = bidorder.ORDERID
WHERE askorder.ORDERID = 2;
我已经尝试此转化为JPQL但我敢肯定这是错的。具体来说,我认为这可能是ON关键字,我不知道如何翻译,为JPQL:
@NamedQuery(
name="findOrderBooksPrices",
query="SELECT ao.price, bo.price from OrderBook bo, OrderBook ao" +
"INNER JOIN ao ON bo.ASKORDERID_ORDERID = ao.ORDERID " +
"INNER JOIN bo ON OrderBook.BIDORDERID_ORDERID = bo.ORDERID " +
"WHERE ao.ORDERID = :askOrderId"
)
我得到的错误是:
Internal Exception: Exception [EclipseLink-7158] (Eclipse Persistence
Services - 2.5.0.v20130507-3faac2b):
org.eclipse.persistence.exceptions.ValidationException
Exception Description: Error encountered when building the @NamedQuery
[findOrderBooksPrices] from entity class [class
org.eclipse.persistence.internal.jpa.metadata.queries.
NamedQueryMetadata].Internal Exception: java.lang.ClassCastException:
org.eclipse.persistence.jpa.jpql.parser.NullExpression cannot be cast to
org.eclipse.persistence.jpa.jpql.parser.IdentificationVariable. Please
see server.log for more details.
我想它返回提交订单ID后,每个订单表的价格。
感谢您寻找。 干杯, Zerb
为什么宥调用表'ao'这里'INNER JOIN AO ON'但在核心的MySQL调用表'JOIN askorder ON'等什么是真实的表名? – Alex
真正的表名是askorder。我刚刚听到我的语法困惑。 – zobbo