mysql - MySQLSyntaxErrorException generated by Hibernate when using count of children in query -

i have query in want retrieve message objects have 1 or more link children.

my message class is:

package zzz.community.domain;  /** * entity implementation class entity: message. */ @entity @table(name = "message") public class message implements serializable {  private static final long serialversionuid = 2252587276028343749l;  public static final int max_length_title = 255;  public static final int max_length_text = 200000;  @id @generatedvalue private long id;  private string title;  @column(columndefinition = "text") private string text;  /**  * date @ message posted.  */ private date creationdate;  /**  * profile id of user posted message.  */ @onetoone private profile creator;  /**  * id of circle message posted to.  */ @onetoone private circle circle;  /**  * when true, members of circle may see message.  */ private boolean membersonly;  @onetomany(mappedby="message") @orderby("id desc") private set<link> links;  public long getid() {     return id; }  public void setid(final long id) {     this.id = id; }  public string gettext() {     return text; }  public void settext(final string text) {     this.text = text; }  public string gettitle() {     return title; }  public void settitle(final string title) {     this.title = title; }  public date getcreationdate() {     return creationdate; }  public void setcreationdate(final date creationdate) {     this.creationdate = creationdate; }  public profile getcreator() {     return creator; }  public void setcreator(final profile creator) {     this.creator = creator; }  public circle getcircle() {     return circle; }  public void setcircle(final circle circle) {     this.circle = circle; }  public boolean getmembersonly() {     return membersonly; }  public void setmembersonly(final boolean membersonly) {     this.membersonly = membersonly; }  public set<link> getlinks() {     return this.links; }  public void setlinks(final set<link> links) {     this.links = links; }  public void addlink(final link link) {     this.links.add(link); }  } 

the jpa query wrote is:

 select m message m   m.circle = :circle   , count(m.links) > 0  order m.creationdate desc 

hibernate parses code correctly (no ast exception) resulting mysql statement not correct , throws mysqlsyntaxerrorexception

 09:01:22.153 [http-apr-8080-exec-3] debug org.hibernate.hql.ast.errorcounter - throwqueryexception() : no errors 09:01:22.154 [http-apr-8080-exec-3] debug o.h.hql.ast.querytranslatorimpl - hql: select m zzz.domain.message m m.circle = :circle , count(m.links) > 0 order m.creationdate desc 09:01:22.154 [http-apr-8080-exec-3] debug o.h.hql.ast.querytranslatorimpl - sql: select message0_.id id3_, message0_.circle_id circle6_3_, message0_.creationdate creation2_3_, message0_.creator_id creator7_3_, message0_.membersonly memberso3_3_, message0_.text text3_, message0_.title title3_ message message0_ cross join link links1_ message0_.id=links1_.message_id , message0_.circle_id=? , count(.)>0 order message0_.creationdate desc 

again, resulting mysql query:

select    message0_.id id3_ , message0_.circle_id circle6_3_ , message0_.creationdate creation2_3_ , message0_.creator_id creator7_3_ , message0_.membersonly memberso3_3_ , message0_.text text3_ , message0_.title title3_  message message0_  cross join link links1_  message0_.id=links1_.message_id  ,   message0_.circle_id=?  ,   count(.)>0  order message0_.creationdate desc 

the workaround, of course, remove selection criterion

count(m.links) > 0 

and replace code in java. hope better suggestion of 1 of you.
in advance,

henk

in jpql can done example 1 of following constructs:

• empty collection comparison expression [not] empty
• size function

with first 1 following:

count(m.links) > 0 

is replaced by:

m.links not empty 

and second approach is:

size(m.links) > 0