JPA Criteria API group_concat usage

Question

I am currently working on a report which needs a group_concat for one of the fields.

CriteriaQuery criteriaQuery = criteriaBuilder
             


        

Answer 1

Simple solution: instead of creating the whole class, just use SQLFunctionTemplate.

new SQLFunctionTemplate(StandardBasicTypes.STRING, "group_concat(?1)")

and then register this function in your own SQL dialect (eg. in constructor)

public class MyOwnSQLDialect extends MySQL5Dialect {

  public MyOwnSQLDialect() {
    super();
    this.registerFunction("group_concat", new SQLFunctionTemplate(StandardBasicTypes.STRING, "group_concat(?1)"));
  }
}