Spring 数据 Jpa JPQL 使用内部连接到 select 最低价假期

Question

我试图从 table 中找到每个月从每个出发机场到目标目的地机场的最低价格假期，记录超过 100 万条。我已成功创建所需的 MySQL 查询：-

SELECT * FROM results r INNER JOIN (SELECT id,MIN(price) FROM results GROUP BY BulkLoaderRef) r2 ON r.id=r2.id ORDER BY r.departureDate, r.depAirportCode, r.resortID LIMIT 10

但是我找不到该查询的有效 JPQL 语法？

请帮忙？

我的table格式如下：-

CREATE TABLE `results` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `HotelReference` varchar(128) NOT NULL DEFAULT '',
  `HotelName` varchar(64) NOT NULL DEFAULT '',
  `Resort` varchar(128) NOT NULL DEFAULT '',
  `Description` longtext NOT NULL,
  `Photo` varchar(255) NOT NULL DEFAULT '',
  `OfferProcessType` varchar(1) NOT NULL DEFAULT 'A',
  `TradingName` varchar(32) NOT NULL DEFAULT 'Heffernans Travel',
  `OfferLabelDesc` varchar(16) NOT NULL DEFAULT 'EasyHolidays',
  `DestinationName` varchar(128) NOT NULL DEFAULT '',
  `DepAirportCode` varchar(3) NOT NULL DEFAULT '',
  `TelephoneNumber` varchar(16) NOT NULL DEFAULT '021 230 0700',
  `ReturnAirportCode` varchar(3) NOT NULL DEFAULT '',
  `ArrivalAirportCode` varchar(3) NOT NULL DEFAULT '',
  `ResortID` int(11) NOT NULL,
  `ABTA` varchar(16) NOT NULL DEFAULT 'ABTA',
  `ATOL` varchar(16) NOT NULL DEFAULT 'ATOL',
  `OtherBonding` varchar(64) NOT NULL DEFAULT 'Agent for ATOL protected operator',
  `BoardTypesShort` varchar(2) NOT NULL DEFAULT '',
  `AccomodationShort` varchar(3) NOT NULL DEFAULT 'Htl',
  `AllocationShort` varchar(3) DEFAULT '""',
  `OperatorShort` varchar(16) NOT NULL DEFAULT 'EasyHolidays',
  `DepartureDate` date NOT NULL,
  `DepartureMonth` varchar(2) DEFAULT NULL,
  `DepartureYear` varchar(4) DEFAULT NULL,
  `Price` int(11) NOT NULL,
  `ShareBasisAdult` int(11) DEFAULT '2',
  `BulkLoaderRef` varchar(64) DEFAULT NULL,
  `Email` varchar(64) DEFAULT '',
  `PublicNotes` varchar(64) DEFAULT 'EasyHolidays',
  `CCC` varchar(32) DEFAULT ' Credit Card Charges',
  `TOD` varchar(16) DEFAULT '',
  `DCC` varchar(16) DEFAULT '',
  `AMEX` varchar(16) DEFAULT '',
  `CDW` varchar(16) DEFAULT '',
  `BookingFee` double DEFAULT NULL,
  `AccomodationName` varchar(64) NOT NULL DEFAULT '',
  `duration` int(11) NOT NULL DEFAULT '0',
  `ShareBasisChild` int(11) DEFAULT '2',
  `Rating` varchar(16) NOT NULL DEFAULT '',
  `OfferLink` varchar(16) NOT NULL DEFAULT '',
  `AccomodationRef` varchar(128) NOT NULL DEFAULT '',
  `Transfers` varchar(32) NOT NULL DEFAULT '',
  `OperatorsRating` varchar(32) NOT NULL DEFAULT '',
  `QuoteRef` varchar(64) NOT NULL DEFAULT '',
  `Url` varchar(128) NOT NULL DEFAULT '',
  `OutDepTime` varchar(16) NOT NULL DEFAULT '',
  `OutArrTime` varchar(16) NOT NULL DEFAULT '',
  `InDepTime` varchar(16) NOT NULL DEFAULT '',
  `InArrTime` varchar(16) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`),
  UNIQUE KEY `HotelReference` (`HotelReference`),
  KEY `BulkLoaderRef` (`BulkLoaderRef`),
  KEY `Price` (`Price`)
) ENGINE=InnoDB AUTO_INCREMENT=1091073 DEFAULT CHARSET=utf8;

Answer 1

JPQL 不支持 JOIN 语句的子查询。话虽如此，我建议您将 JOIN 的子查询移动到视图中。那么就变成了一个简单的JPQL语句。

将子查询移动到视图中：

CREATE VIEW min_price_view AS 
    SELECT id,MIN(price) FROM results GROUP BY BulkLoaderRef;

然后在查询中替换：

SELECT 
    * 
FROM 
    results r 
INNER JOIN 
    min_price_view r2 ON r.id=r2.id 
ORDER BY 
    r.departureDate, r.depAirportCode, r.resortID 
LIMIT 10

至此，转成JPQL就变得很简单了

Spring 数据 Jpa JPQL 使用内部连接到 select 最低价假期

Spring Data Jpa JPQL using inner join to select minimum priced holiday

spring

jpa

jpql

spring-data-jpa