java - QueryDSL 使用本机 SQL 连接和子查询

Question

我使用 Spring Data 和 QueryDSL 3.2.4，我想使用 QueryDSLs 原生 SQL API 实现以下 SQL 查询：

WITH ORDER_GROUP AS (   -- TODO have to merge this subquery into the main query
    SELECT 
        ordergroup
       ,count(ID) AS nofOrdersPerGroup 
       ,MIN(priority) as minPriority
       ,MIN(requesteddeliverytime) as minRequestedDeliveryTime
       ,MIN(creationtime) as minCreationTime
      FROM ORDERHEADER hh
     group by orderGroup      
),
ALL_ORDERS AS (   -- TODO have to merge this subquery into the main query
    SELECT h.ordercode
      , h.ordergroup
      , h.priority
      , h.requesteddeliverytime
      , h.creationtime
      , h.statecode
      , (SELECT COUNT(ID)
           FROM orderposition p
          WHERE p.orderheaderid = h.ID
        ) AS nof_positions_per_order
      , CASE
            WHEN h.ordergroup IS NOT NULL
            THEN g.nofOrdersPerGroup
            ELSE 1
        END AS nof_orders_per_group
      , CASE
            WHEN h.ordergroup IS NOT NULL
            THEN g.minPriority
            ELSE h.priority
        END AS most_important_prio
      , CASE
            WHEN h.ordergroup IS NOT NULL
            THEN g.minRequestedDeliveryTime
            ELSE h.requesteddeliverytime
        END AS earliest_del_time
      , CASE
            WHEN h.ordergroup IS NOT NULL
            THEN g.minCreationTime
            ELSE h.creationtime
        END AS earliest_cre_time
       FROM ORDERHEADER h left outer join ORDER_GROUP g on h.ordergroup = g.ordergroup
      WHERE 1=1  -- TODO have to add filter clauses here
)
 SELECT ordercode
  , ordergroup
  , priority
  , requesteddeliverytime
  , creationtime
  , statecode
  , nof_positions_per_order
  , nof_orders_per_group
  , most_important_prio
  , earliest_del_time
  , earliest_cre_time
   FROM ALL_ORDERS
ORDER BY most_important_prio
  , earliest_del_time
  , earliest_cre_time
  , priority
  , requesteddeliverytime
  , creationtime;

联接不在 FK 列上，而是在子查询 ORDER_GROUP 的某个任意属性上。此子查询聚合 OrderHeader 上的一些最小/最大值，以供以后在排序中使用。

查询类型有：

package com.stoecklin.wms.entity;

import static com.mysema.query.types.PathMetadataFactory.*;

import com.mysema.query.types.path.*;

import com.mysema.query.types.PathMetadata;
import javax.annotation.Generated;
import com.mysema.query.types.Path;
import com.mysema.query.types.path.PathInits;


/**
 * QOrderHeader is a Querydsl query type for OrderHeader
 */
@Generated("com.mysema.query.codegen.EntitySerializer")
public class QOrderHeader extends EntityPathBase<OrderHeader> {

    private static final long serialVersionUID = 2006939562;
    public static final QOrderHeader orderHeader = new QOrderHeader("orderHeader");
    public final com.stoecklin.utility.database.QBaseEntity _super = new com.stoecklin.utility.database.QBaseEntity(this);
    public final DateTimePath<java.util.Date> actualDeliveryTime = createDateTime("actualDeliveryTime", java.util.Date.class);
    public final StringPath creationMode = createString("creationMode");
    //inherited
    public final DateTimePath<java.util.Date> creationTime = _super.creationTime;
    public final StringPath customerCode = createString("customerCode");
    public final StringPath customerOrderCode = createString("customerOrderCode");
    public final StringPath deliveryCode = createString("deliveryCode");
    public final StringPath deliveryNote = createString("deliveryNote");
    public final StringPath headerText = createString("headerText");
    public final NumberPath<Integer> hostId = createNumber("hostId", Integer.class);
    public final NumberPath<Long> id = createNumber("id", Long.class);
    //inherited
    public final DateTimePath<java.util.Date> lastUpdateTime = _super.lastUpdateTime;
    public final StringPath orderCode = createString("orderCode");
    public final StringPath orderGroup = createString("orderGroup");
    public final ListPath<OrderPosition, QOrderPosition> orderPositions = this.<OrderPosition, QOrderPosition>createList("orderPositions", OrderPosition.class, QOrderPosition.class, PathInits.DIRECT2);
    public final StringPath orderTypeCode = createString("orderTypeCode");
    public final StringPath priority = createString("priority");
    public final DateTimePath<java.util.Date> requestedDeliveryTime = createDateTime("requestedDeliveryTime", java.util.Date.class);
    public final StringPath setupType = createString("setupType");
    public final StringPath shippingMode = createString("shippingMode");
    public final StringPath stagingArea = createString("stagingArea");
    public final EnumPath<com.stoecklin.wms.enums.OrderHeaderState> stateCode = createEnum("stateCode", com.stoecklin.wms.enums.OrderHeaderState.class);
    public final StringPath stateReason = createString("stateReason");
    public final DateTimePath<java.util.Date> stateTime = createDateTime("stateTime", java.util.Date.class);
    //inherited
    public final NumberPath<Long> version = _super.version;

    public QOrderHeader(String variable) {
        super(OrderHeader.class, forVariable(variable));
    }

    public QOrderHeader(Path<? extends OrderHeader> path) {
        super(path.getType(), path.getMetadata());
    }

    public QOrderHeader(PathMetadata<?> metadata) {
        super(OrderHeader.class, metadata);
    }

}

和

package com.stoecklin.wms.entity;

import static com.mysema.query.types.PathMetadataFactory.*;

import com.mysema.query.types.path.*;

import com.mysema.query.types.PathMetadata;
import javax.annotation.Generated;
import com.mysema.query.types.Path;
import com.mysema.query.types.path.PathInits;


/**
 * QOrderPosition is a Querydsl query type for OrderPosition
 */
@Generated("com.mysema.query.codegen.EntitySerializer")
public class QOrderPosition extends EntityPathBase<OrderPosition> {

    private static final long serialVersionUID = 2091670278;
    private static final PathInits INITS = PathInits.DIRECT2;
    public static final QOrderPosition orderPosition = new QOrderPosition("orderPosition");
    public final com.stoecklin.utility.database.QBaseEntity _super = new com.stoecklin.utility.database.QBaseEntity(this);
    public final StringPath articleCode = createString("articleCode");
    //inherited
    public final DateTimePath<java.util.Date> creationTime = _super.creationTime;
    public final NumberPath<Integer> customerOrderPos = createNumber("customerOrderPos", Integer.class);
    public final NumberPath<Float> deliveredQuantity = createNumber("deliveredQuantity", Float.class);
    public final StringPath fromWarehouseCode = createString("fromWarehouseCode");
    public final StringPath hostData = createString("hostData");
    public final StringPath hostRef = createString("hostRef");
    public final NumberPath<Long> id = createNumber("id", Long.class);
    //inherited
    public final DateTimePath<java.util.Date> lastUpdateTime = _super.lastUpdateTime;
    public final StringPath lotCode = createString("lotCode");
    public final NumberPath<Float> missingQuantity = createNumber("missingQuantity", Float.class);
    public final QOrderHeader orderHeader;
    public final NumberPath<Integer> orderPos = createNumber("orderPos", Integer.class);
    public final StringPath ownerCode = createString("ownerCode");
    public final StringPath posText = createString("posText");
    public final NumberPath<Float> requestedQuantity = createNumber("requestedQuantity", Float.class);
    public final EnumPath<com.stoecklin.wms.enums.OrderPositionState> stateCode = createEnum("stateCode", com.stoecklin.wms.enums.OrderPositionState.class);
    public final StringPath stateReason = createString("stateReason");
    public final DateTimePath<java.util.Date> stateTime = createDateTime("stateTime", java.util.Date.class);
    public final StringPath toBePicked = createString("toBePicked");
    public final StringPath toLocation = createString("toLocation");
    //inherited
    public final NumberPath<Long> version = _super.version;

    public QOrderPosition(String variable) {
        this(OrderPosition.class, forVariable(variable), INITS);
    }

    public QOrderPosition(Path<? extends OrderPosition> path) {
        this(path.getType(), path.getMetadata(), path.getMetadata().isRoot() ? INITS : PathInits.DEFAULT);
    }

    public QOrderPosition(PathMetadata<?> metadata) {
        this(metadata, metadata.isRoot() ? INITS : PathInits.DEFAULT);
    }

    public QOrderPosition(PathMetadata<?> metadata, PathInits inits) {
        this(OrderPosition.class, metadata, inits);
    }

    public QOrderPosition(Class<? extends OrderPosition> type, PathMetadata<?> metadata, PathInits inits) {
        super(type, metadata, inits);
        this.orderHeader = inits.isInitialized("orderHeader") ? new QOrderHeader(forProperty("orderHeader")) : null;
    }

}

现在的问题：

如何在 ALL_ORDERS 子查询的底部进行连接？我已经尝试了以下方法：

QOrderHeader orderHeader = QOrderHeader.orderHeader;
QOrderHeader orderHeaderGroup = new QOrderHeader("orderHeaderGroup");
QOrderPosition orderPosition = QOrderPosition.orderPosition;

List<Tuple> tuples = query.from(orderHeader)
        .leftJoin(orderHeader, orderHeaderGroup).on(orderHeader.orderGroup.eq(orderHeaderGroup.orderGroup))
        .list(
                orderHeader.orderGroup,
                orderHeader.id
              );

但这甚至不会编译，因为没有匹配的方法 leftJoin 可用。连接不在 FK 列上，而是在某个任意属性上。子查询 ORDER_GROUP

如何实现计算 nof_orders_per_group（SELECT 列表中的第 7 项）的相关子查询？（我不知道如何做到这一点:-)）

顶部显示的 SQL 在某种程度上针对效率进行了优化。出于这个原因，我决定使用原生 SQL，因为我们到处都有子查询。

任何帮助表示赞赏。

score 1 · Accepted Answer

如果您想将 Querydsl 与 SQL 一起使用，则需要以不同的方式创建元模型，此处描述为http://www.querydsl.com/static/querydsl/3.2.4/reference/html/ch02s03.html

对于您更具体的问题：

1) FROM ORDERHEADER h 左外连接 ORDER_GROUP g on h.ordergroup = g.ordergroup

from(h).leftJoin(g).on(h.ordergroup.eq(g.ordergroup))

2) 当 h.ordergroup 不为 NULL 时的情况下 g.nofOrdersPerGroup ELSE 1 END AS nof_orders_per_group

new CaseBuilder()
    .when(h.ordergroup.isNotNull()).then(g.nofOrderPerGroup)
    .otherwise(1)

关于查询构造，联接的工作方式与 JPA 不同

查询dsl JPA

query.join(entity.property, reference)

查询dsl SQL

query.join(table).on(condition)

或者

query.join(table.fk, otherTable)

java - QueryDSL 使用本机 SQL 连接和子查询

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