@Override
public void meet(Count node) throws RuntimeException {
builder.append("COUNT(");
if (node.isDistinct()) {
builder.append("DISTINCT ");
}
if (node.getArg() == null) {
// this is a weird special case where we need to expand to all variables selected in the query
// wrapped
// by the group; we cannot simply use "*" because the concept of variables is a different one
// in SQL,
// so instead we construct an ARRAY of the bindings of all variables
List<String> countVariables = new ArrayList<>();
for (SQLVariable v : parent.getVariables().values()) {
if (v.getProjectionType() == ValueType.NONE) {
Preconditions.checkState(
v.getExpressions().size() > 0, "no expressions available for variable");
countVariables.add(v.getExpressions().get(0));
}
}
builder.append("ARRAY[");
Joiner.on(',').appendTo(builder, countVariables);
builder.append("]");
} else {
optypes.push(ValueType.NODE);
node.getArg().visit(this);
optypes.pop();
}
builder.append(")");
}
@Override
public int compare(Tuple<Text, Integer> o1, Tuple<Text, Integer> o2) {
return -count.compare(o1, o2);
}