@Override
    protected Boolean visitCoalesceExpression(CoalesceExpression node, Void context) {
      return node.getOperands().stream().allMatch(expression -> process(expression, context));
    }
visitor returns true if all expressions are constant with respect to the group.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/analyzer/AggregationAnalyzer.java