expression: do not bind column for count(*) in binder

[skyzh]

risinglight/src/binder/expression/agg_call.rs

Lines 65 to 83 in 40db687

	if args.is_empty() {
	for ref_id in self.context.regular_tables.values() {
	let table = self.catalog.get_table(ref_id).unwrap();
	if let Some(col) = table.get_column_by_id(0) {
	let column_ref_id = ColumnRefId::from_table(*ref_id, col.id());
	self.record_regular_table_column(
	&table.name(),
	col.name(),
	col.id(),
	col.desc().clone(),
	);
	let expr = BoundExpr::ColumnRef(BoundColumnRef {
	table_name: table.name(),
	column_ref_id,
	is_primary_key: col.is_primary(),
	desc: col.desc().clone(),
	});
	args.push(expr);
	break;

Currently, we always select the 0th column in binder for count(*). This has caused problems like #200. In the future, we should be able to do both of the following:

• bind all columns in binder, and do column prune in optimizer
• rewrite count(*) to using statistics information (only for queries like select count(*) from table)

[likg227]

I will solve this problem after @st1page finishes his work.