How to use

emulateNullDirection

method

in

org.apache.calcite.sql.SqlDialect

public void addOrderItem(List<SqlNode> orderByList,
  RelFieldCollation field) {
 if (field.nullDirection != RelFieldCollation.NullDirection.UNSPECIFIED) {
  boolean first = field.nullDirection == RelFieldCollation.NullDirection.FIRST;
  SqlNode nullDirectionNode =
    dialect.emulateNullDirection(context.field(field.getFieldIndex()),
      first, field.direction.isDescending());
  if (nullDirectionNode != null) {
   orderByList.add(nullDirectionNode);
   field = new RelFieldCollation(field.getFieldIndex(),
     field.getDirection(),
     RelFieldCollation.NullDirection.UNSPECIFIED);
  }
 }
 orderByList.add(context.toSql(field));
}

void addOrderItem(List<SqlNode> orderByList, RelFieldCollation field) {
 if (field.nullDirection != RelFieldCollation.NullDirection.UNSPECIFIED) {
  final boolean first =
    field.nullDirection == RelFieldCollation.NullDirection.FIRST;
  SqlNode nullDirectionNode =
    dialect.emulateNullDirection(field(field.getFieldIndex()),
      first, field.direction.isDescending());
  if (nullDirectionNode != null) {
   orderByList.add(nullDirectionNode);
   field = new RelFieldCollation(field.getFieldIndex(),
     field.getDirection(),
     RelFieldCollation.NullDirection.UNSPECIFIED);
  }
 }
 orderByList.add(toSql(field));
}

boolean first = fc.nullDirection == RelFieldCollation.NullDirection.FIRST;
SqlNode nullDirectionNode =
  dialect.emulateNullDirection(context.field(fc.getFieldIndex()),
    first, fc.direction.isDescending());
if (nullDirectionNode != null) {

boolean first = fc.nullDirection == RelFieldCollation.NullDirection.FIRST;
SqlNode nullDirectionNode =
  dialect.emulateNullDirection(context.field(fc.getFieldIndex()),
    first, fc.direction.isDescending());
if (nullDirectionNode != null) {