Feat: support covar, corr functions

Author: taewhi

traindb-core/src/main/codegen/templates/Parser.jj

@@ -7027,6 +7027,7 @@ SqlIdentifier ReservedFunctionName() :
  | <CHARACTER_LENGTH>
  | <COALESCE>
  | <COLLECT>
+ | <CORR>
  | <COVAR_POP>
  | <COVAR_SAMP>
  | <CUME_DIST>

traindb-core/src/main/java/traindb/jdbc/TrainDBMetaImpl.java

@@ -81,6 +81,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.regex.Pattern;
+import traindb.sql.fun.TrainDBAggregateOperatorTable;
 import traindb.sql.fun.TrainDBSpatialOperatorTable;
 
 import static java.util.Objects.requireNonNull;
@@ -531,6 +532,7 @@ Enumerable<MetaFunction> functions(final MetaSchema schema_, final String catalo
  SqlOperatorTable opTable = getConnection().config()
  .fun(SqlOperatorTable.class,
  SqlOperatorTables.chain(SqlStdOperatorTable.instance(),
+ TrainDBAggregateOperatorTable.instance(),
  TrainDBSpatialOperatorTable.instance()));
  List<SqlOperator> q = opTable.getOperatorList();
  opTableFunctions = Linq4j.asEnumerable(q)

traindb-core/src/main/java/traindb/planner/TrainDBPlanner.java

@@ -107,6 +107,8 @@ public void initPlanner() {
  RelOptUtil.registerDefaultRules(this, true, Hook.ENABLE_BINDABLE.get(false));
  removeRule(CoreRules.FILTER_REDUCE_EXPRESSIONS);
  removeRule(CoreRules.AGGREGATE_CASE_TO_FILTER);
+ removeRule(CoreRules.AGGREGATE_REDUCE_FUNCTIONS);
+ addRule(TrainDBRules.AGGREGATE_REDUCE_FUNCTIONS);
  addRelTraitDef(ConventionTraitDef.INSTANCE);
  addRelTraitDef(RelCollationTraitDef.INSTANCE);
  setTopDownOpt(false);