/**
* Return true if 'this' and other have compatible partition exprs and our orderByElements are a
* prefix of other's.
*/
public boolean isPrefixOf(SortGroup other) {
if (other.orderByElements.size() > orderByElements.size()) return false;
if (!Expr.equalSets(partitionByExprs, other.partitionByExprs)) return false;
for (int i = 0; i < other.orderByElements.size(); ++i) {
OrderByElement ob = orderByElements.get(i);
OrderByElement otherOb = other.orderByElements.get(i);
// TODO: compare equiv classes by comparing each equiv class's placeholder
// slotref
if (!ob.getExpr().equals(otherOb.getExpr())) return false;
if (ob.isAsc() != otherOb.isAsc()) return false;
if (ob.nullsFirst() != otherOb.nullsFirst()) return false;
}
return true;
}
