public static RelDataType createTypeFromProjection(
RelDataType type,
List<String> columnNameList,
RelDataTypeFactory typeFactory,
boolean caseSensitive) {
// If the names in columnNameList and type have case-sensitive differences,
// the resulting type will use those from type. These are presumably more
// canonical.
final List<RelDataTypeField> fields = new ArrayList<RelDataTypeField>(columnNameList.size());
for (String name : columnNameList) {
RelDataTypeField field = type.getField(name, caseSensitive);
fields.add(type.getFieldList().get(field.getIndex()));
}
return typeFactory.createStructType(fields);
}
public int fieldOrdinal(RelDataType rowType, String alias) {
RelDataTypeField field = field(rowType, alias);
return field != null ? field.getIndex() : -1;
}