引起：org.hibernate.hql.internal.ast.QuerySyntaxException：无法解析属性：产品线：答案

【问题标题】：Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: could not resolve property: productline of:引起：org.hibernate.hql.internal.ast.QuerySyntaxException：无法解析属性：产品线：
【发布时间】：2020-04-16 11:13:43
【问题描述】：

我想编写以下查询的 JPQL。我正在使用 Spring Boot v.2.2.2.RELEASE 和 Spring Data JPA。

错误：

Caused by: org.hibernate.QueryException: could not resolve property: productline of: com.example.entity.Productline [SELECT p FROM com.example.entity.Product p JOIN p.productline pl WHERE p.productline = pl.productline]
    at org.hibernate.QueryException.generateQueryException(QueryException.java:120) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.QueryException.wrapWithQueryString(QueryException.java:103) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:220) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:144) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:113) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:73) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:155) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.internal.AbstractSharedSessionContract.getQueryPlan(AbstractSharedSessionContract.java:600) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.internal.AbstractSharedSessionContract.createQuery(AbstractSharedSessionContract.java:709) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    ... 66 common frames omitted
Caused by: org.hibernate.QueryException: could not resolve property: productline of: com.example.entity.Productline
    at org.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:73) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.persister.entity.AbstractPropertyMapping.toType(AbstractPropertyMapping.java:67) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.persister.entity.AbstractEntityPersister.toType(AbstractEntityPersister.java:2015) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.tree.FromElementType.getPropertyType(FromElementType.java:407) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.tree.FromElement.getPropertyType(FromElement.java:516) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.tree.DotNode.getDataType(DotNode.java:697) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.tree.DotNode.prepareLhs(DotNode.java:275) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.tree.DotNode.resolve(DotNode.java:215) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.HqlSqlWalker.resolve(HqlSqlWalker.java:1045) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.expr(HqlSqlBaseWalker.java:1290) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.exprOrSubquery(HqlSqlBaseWalker.java:4706) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.comparisonExpr(HqlSqlBaseWalker.java:4177) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.logicalExpr(HqlSqlBaseWalker.java:2138) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.whereClause(HqlSqlBaseWalker.java:815) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:609) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:313) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:261) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:272) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:192) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    ... 72 common frames omitted

选择查询

SELECT 
    productCode, 
    productName, 
    textDescription
FROM
    products t1
INNER JOIN productlines t2 
    ON t1.productline = t2.productline;

存储库

public interface ProductRepository extends JpaRepository<Product, String>{

    @Query("SELECT p FROM Product p INNER JOIN p.productline pl ON p.productline=pl.productline")
    List<Product> findProductsAndProductLines(); 
}

Product.java

@Entity
@Table(name="products")
@NamedQuery(name="Product.findAll", query="SELECT p FROM Product p")
public class Product implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(unique=true, nullable=false, length=15)
    private String productCode;

    @Column(nullable=false, precision=10, scale=2)
    private BigDecimal buyPrice;

    @Column(nullable=false, precision=10, scale=2)
    private BigDecimal msrp;

    @Lob
    @Type(type = "text")
    @Column(nullable=false)
    private String productDescription;

    @Column(nullable=false, length=70)
    private String productName;

    @Column(nullable=false, length=10)
    private String productScale;

    @Column(nullable=false, length=50)
    private String productVendor;

    @Column(nullable=false)
    private short quantityInStock;

    //bi-directional many-to-one association to Orderdetail
    @OneToMany(mappedBy="product")
    private List<Orderdetail> orderdetails;

    //bi-directional many-to-one association to Productline
    @ManyToOne
    @JoinColumn(name="productLine", nullable=false)
    private Productline productline;

    public Product() {
    }

    public String getProductCode() {
        return this.productCode;
    }

    public void setProductCode(String productCode) {
        this.productCode = productCode;
    }

    public BigDecimal getBuyPrice() {
        return this.buyPrice;
    }

    public void setBuyPrice(BigDecimal buyPrice) {
        this.buyPrice = buyPrice;
    }

    public BigDecimal getMsrp() {
        return this.msrp;
    }

    public void setMsrp(BigDecimal msrp) {
        this.msrp = msrp;
    }

    public String getProductDescription() {
        return this.productDescription;
    }

    public void setProductDescription(String productDescription) {
        this.productDescription = productDescription;
    }

    public String getProductName() {
        return this.productName;
    }

    public void setProductName(String productName) {
        this.productName = productName;
    }

    public String getProductScale() {
        return this.productScale;
    }

    public void setProductScale(String productScale) {
        this.productScale = productScale;
    }

    public String getProductVendor() {
        return this.productVendor;
    }

    public void setProductVendor(String productVendor) {
        this.productVendor = productVendor;
    }

    public short getQuantityInStock() {
        return this.quantityInStock;
    }

    public void setQuantityInStock(short quantityInStock) {
        this.quantityInStock = quantityInStock;
    }

    public List<Orderdetail> getOrderdetails() {
        return this.orderdetails;
    }

    public void setOrderdetails(List<Orderdetail> orderdetails) {
        this.orderdetails = orderdetails;
    }

    public Orderdetail addOrderdetail(Orderdetail orderdetail) {
        getOrderdetails().add(orderdetail);
        orderdetail.setProduct(this);

        return orderdetail;
    }

    public Orderdetail removeOrderdetail(Orderdetail orderdetail) {
        getOrderdetails().remove(orderdetail);
        orderdetail.setProduct(null);

        return orderdetail;
    }

    public Productline getProductline() {
        return this.productline;
    }

    public void setProductline(Productline productline) {
        this.productline = productline;
    }
}

Productline.java

@Entity
@Table(name="productlines")
@NamedQuery(name="Productline.findAll", query="SELECT p FROM Productline p")
public class Productline implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(unique=true, nullable=false, length=50)
    private String productLine;

    @Lob
    @Type(type = "text")
    private String htmlDescription;

    // Ref: https://docs.jboss.org/hibernate/orm/5.0/mappingGuide/en-US/html/ch03.html
    @Lob
    @Type(type="org.hibernate.type.ImageType")
    private byte[] image;

    @Column(length=4000)
    private String textDescription;

    //bi-directional many-to-one association to Product
    @OneToMany(mappedBy="productline")
    private List<Product> products;

    public Productline() {
    }

    public String getProductLine() {
        return this.productLine;
    }

    public void setProductLine(String productLine) {
        this.productLine = productLine;
    }

    public String getHtmlDescription() {
        return this.htmlDescription;
    }

    public void setHtmlDescription(String htmlDescription) {
        this.htmlDescription = htmlDescription;
    }

    public byte[] getImage() {
        return this.image;
    }

    public void setImage(byte[] image) {
        this.image = image;
    }

    public String getTextDescription() {
        return this.textDescription;
    }

    public void setTextDescription(String textDescription) {
        this.textDescription = textDescription;
    }

    public List<Product> getProducts() {
        return this.products;
    }

    public void setProducts(List<Product> products) {
        this.products = products;
    }

    public Product addProduct(Product product) {
        getProducts().add(product);
        product.setProductline(this);

        return product;
    }

    public Product removeProduct(Product product) {
        getProducts().remove(product);
        product.setProductline(null);

        return product;
    }
}

【问题讨论】：

您是否可以尝试使用 p.productLine 仅作为您定义的产品实体参考 @JoinColumn(name="productLine")
@MyTwoCents - 对不起，我没有关注你。你能解释一下吗？

标签： spring hibernate spring-boot spring-data-jpa jpql

【解决方案1】：

由于这一行p.productline=pl.productline，您会遇到错误

Productline 实体没有产品线。

使用p.productline，所有映射都会得到照顾。 INNER 也是可选的。

你的最终查询应该是这样的

@Query("SELECT p FROM Product p JOIN p.productline pl")
List<Product> findProductsAndProductLines();

更多详情请参考Doc

【讨论】：

在 JPQL 之上和 SELECT productCode, productName, textDescription FROM products t1 INNER JOIN productlines t2 ON t1.productline = t2.productline;两者是等价的？
当您在查询中添加 p.productline 时，hibernate 会将其映射为内部连接查询。所以是的，它们是一样的。您可以尝试在控制台中运行并检查查询。如果查询打印启用
太棒了！感谢您的确认。您能否提供此类信息的文档链接？我正在尝试在 JPQL 中加入 Left Outer Join 希望这会起作用
我刚刚跑了：@Query("SELECT c.customerNumber, c.customerName, o.orderNumber,o.status FROM Customer c LEFT JOIN c.orders o")，控制台显示elect customer0_.customerNumber as col_0_0_, customer0_.customerName as col_1_0_, orders1_.orderNumber as col_2_0_, orders1_.status as col_3_0_ from customers customer0_ left outer join orders orders1_ on customer0_.customerNumber=orders1_.customerNumber，所以非常完美
docs.oracle.com/html/E13946_04/…

【解决方案2】：

提供的代码 sn-p 存在一些问题。

默认情况下，您应该将 JPQL 查询传递给您的 @Query 注释。这意味着 您不应该编写手动 JOIN 运算符。 例如SELECT p FROM Product p join p.productline 将产生正确的 SQL。但是，您不应该这样做。
JpaRepository 提供所有常用方法。所以你可以使用findAll()，获取所有产品。 在这种情况下，将为每个产品自动加载一个productLine。这是因为toOne 关系的默认获取类型是EAGER。这意味着每次加载实体时，JPA 提供程序（在本例中为 Hibernate）将加载其toOne 关系。
如果你想强制 Spring Data 生成一个INNER JOIN，你应该告诉它这个关系不是可选的。您可以通过将@ManyToOne(optional=false) 放在productLine 上来做到这一点。

您的问题的答案：该错误是由语法错误引起的，ON p.productline=pl.productline。如您所见，pl 没有productLine 字段。 为了使用INNER JOIN 获得所需的SQL 查询，请遵循上面的3 条建议。

【讨论】：