Hibernate Criteria Query - Order by Two Columns Simultaneously

Question

I came across recently was trying to order a Hibernate Criteria Query by two columns of equal importance. Basically what I mean is, if I have a table where one column is a date (createdOnDate) and the other is a date (modifiedOnDate), I’d like to compare all dates in the orderBy clause from Organization object.

for this i tried like this:

session.createCriteria(Organization.class).addOrder(Order.desc("modified_date")).addOrder( Order.desc("created_date") ).list();

But it is sorting all the organizations first based on the modified_date and then again it is sorting using created_date. This means a modified record could appear before any createdOn records, even if the createdOnDate is earlier.

I need sorting happens simaltaneously with created_date & modified_date.

Please help for this.

Thanks in advance.

Answer 1

You can use "COALESCE()" function in sql to take value from two column when first one will be null than it will take second column,

ORDER BY COALESCE( alias_1.modified_date, alias_1.created_date ) ASC;

So it means if value present in "modified_date" column take for sorting if not present than take from "created_date" for sorting.

In hibernate criteria for COALESCE() function i think there is no Order Bean so you can extend and write your own implementation.

Just like this, if wrong please correct me.

public class CoalesceOrder extends Order {
private String[] properties;

protected CoalesceOrder(boolean ascending, String... properties) {
    super(properties.toString(), ascending);
    this.properties = properties;
}

@Override
public String toSqlString(Criteria criteria, CriteriaQuery criteriaQuery)
        throws HibernateException {

    StringBuilder fragment = new StringBuilder();
    StringBuilder exp = new StringBuilder();
    fragment.append("COALESCE(");
    SessionFactoryImplementor factory = criteriaQuery.getFactory();
    for (int j = 0; j < this.properties.length; j++) {
        String propertyName = this.properties[j];
        String[] columns = criteriaQuery.getColumnsUsingProjection(
                criteria, propertyName);
        Type type = criteriaQuery.getTypeUsingProjection(criteria,
                propertyName);
        StringBuilder fragForField = new StringBuilder();
        for (int i = 0; i < columns.length; i++) {
            final StringBuilder expression = new StringBuilder();
            boolean lower = false;
            if (super.isIgnoreCase()) {
                int sqlType = type.sqlTypes(factory)[i];
                lower = sqlType == Types.VARCHAR || sqlType == Types.CHAR
                        || sqlType == Types.LONGVARCHAR;
            }

            if (lower) {
                expression.append(
                        factory.getDialect().getLowercaseFunction())
                        .append('(');
            }
            expression.append(columns[i]);
            if (lower)
                expression.append(')');
            fragForField.append(expression.toString());
            if (i < columns.length - 1)
                fragForField.append(", ");
        }
        exp.append(fragForField.toString());
        if (j < properties.length - 1)
            exp.append(", ");
    }
    exp.append(")");

    fragment.append(factory.getDialect().renderOrderByElement(
            exp.toString(), null, super.isAscending() ? "asc" : "desc",
            factory.getSettings().getDefaultNullPrecedence()));
    return fragment.toString();
}

public static Order asc(String... properties) {
    return new CoalesceOrder(true, properties);
}

public static Order desc(String... properties) {
    return new CoalesceOrder(false, properties);
}
}

you can add Order now like

criteria.addOrder(CoalesceOrder.desc("modified_date", "created_date"));