Question

I’m trying to use the following code

Query query;
query = entityManager.createQuery("SELECT g.name FROM group g INNER JOIN user_group ug INNER JOIN user u ON u.id = ug.userid AND ug.groupoid = g.id AND u.name = ?1 AND u.password = ?2");
query.setParameter(1, user.getName());
query.setParameter(2, user.getPassword());

Object result = (Object) query.getSingleResult();
String name = (String) result;

And I am getting the following exception when i run the code

Caused by: Exception [EclipseLink-8023] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Syntax error parsing the query [SELECT g.name FROM group g INNER JOIN user_group ug INNER JOIN user u ON u.id = ug.userid AND ug.groupoid = g.id AND u.name = ?1 AND u.password = ?2].
Internal Exception: org.eclipse.persistence.internal.libraries.antlr.runtime.EarlyExitException
    at org.eclipse.persistence.exceptions.JPQLException.syntaxError(JPQLException.java:352)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.handleRecognitionException(JPQLParser.java:354)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.addError(JPQLParser.java:246)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.reportError(JPQLParser.java:363)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.joinAssociationPathExpression(JPQLParser.java:2746)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.join(JPQLParser.java:2364)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.identificationVariableDeclaration(JPQLParser.java:2179)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.fromClause(JPQLParser.java:2043)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.selectStatement(JPQLParser.java:364)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.antlr.JPQLParser.document(JPQLParser.java:281)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.parse(JPQLParser.java:134)
    at org.eclipse.persistence.internal.jpa.parsing.jpql.JPQLParser.buildParseTree(JPQLParser.java:95)
    at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:215)
    at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:190)
    at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:142)
    at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:126)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.createQuery(EntityManagerImpl.java:1475)
    ... 71 more

When I run the sql code on mysql console, it works. I guess I am not doing the JPQL correctly.

Does anyone know how to make the correct query?

EDIT: My Group class is:

    /*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package model.entities;

import java.io.Serializable;
import java.util.Collection;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;

/**
 *
 * @author Felipe
 */
@Entity
@Table(name = "grupo")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "Grupo.findAll", query = "SELECT g FROM Grupo g"),
    @NamedQuery(name = "Grupo.findById", query = "SELECT g FROM Grupo g WHERE g.id = :id"),
    @NamedQuery(name = "Grupo.findByNome", query = "SELECT g FROM Grupo g WHERE g.nome = :nome")})
public class Grupo implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "Id")
    private Integer id;
    @Size(max = 255)
    @Column(name = "Nome")
    private String nome;
    @JoinTable(name = "usuario_grupo", joinColumns = {
        @JoinColumn(name = "GrupoID", referencedColumnName = "Id")}, inverseJoinColumns = {
        @JoinColumn(name = "UsuarioID", referencedColumnName = "Id")})
    @ManyToMany(fetch = FetchType.EAGER)
    private Collection<Usuario> usuarioCollection;

    public Grupo() {
    }

    public Grupo(Integer id) {
        this.id = id;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getNome() {
        return nome;
    }

    public void setNome(String nome) {
        this.nome = nome;
    }

    @XmlTransient
    public Collection<Usuario> getUsuarioCollection() {
        return usuarioCollection;
    }

    public void setUsuarioCollection(Collection<Usuario> usuarioCollection) {
        this.usuarioCollection = usuarioCollection;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Grupo)) {
            return false;
        }
        Grupo other = (Grupo) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "model.entities.Grupo[ id=" + id + " ]";
    }

}

And my User class is:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package model.entities;

import java.io.Serializable;
import java.util.Collection;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;

/**
 *
 * @author Felipe
 */
@Entity
@Table(name = "usuario")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "Usuario.findAll", query = "SELECT u FROM Usuario u"),
    @NamedQuery(name = "Usuario.findById", query = "SELECT u FROM Usuario u WHERE u.id = :id"),
    @NamedQuery(name = "Usuario.findBySenha", query = "SELECT u FROM Usuario u WHERE u.senha = :senha"),
    @NamedQuery(name = "Usuario.findByNome", query = "SELECT u FROM Usuario u WHERE u.nome = :nome")})
public class Usuario implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "Id")
    private Integer id;
    @Size(max = 255)
    @Column(name = "Senha")
    private String senha;
    @Size(max = 255)
    @Column(name = "Nome")
    private String nome;
    @ManyToMany(mappedBy = "usuarioCollection", fetch = FetchType.EAGER)
    private Collection<Grupo> grupoCollection;

    public Usuario() {
    }

    public Usuario(Integer id) {
        this.id = id;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getSenha() {
        return senha;
    }

    public void setSenha(String senha) {
        this.senha = senha;
    }

    public String getNome() {
        return nome;
    }

    public void setNome(String nome) {
        this.nome = nome;
    }

    @XmlTransient
    public Collection<Grupo> getGrupoCollection() {
        return grupoCollection;
    }

    public void setGrupoCollection(Collection<Grupo> grupoCollection) {
        this.grupoCollection = grupoCollection;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Usuario)) {
            return false;
        }
        Usuario other = (Usuario) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "model.entities.Usuario[ id=" + id + " ]";
    }

}

NOTE: These classes was generated by Netbeans.
NOTE2: Some names are in portuguese.

Answer 1

Actually if you want to get group name by user name and password you could rewrite your query as follows:

SELECT g.nome FROM Grupo g INNER JOIN g.usuarioCollection u 
WHERE u.nome = ?1 AND u.senha = ?2

Since in JPQL you’re working with objects not with tables you will use in JOIN clauses association fields that is fields annotated with @OneToMany and @ManyToMany.