fix aggregate all key is null error

Author: liuneng1994

src/Interpreters/Aggregator.cpp

@@ -2102,6 +2102,8 @@ Aggregator::convertToBlockImplNotFinal(Method & method, Table & data, Arenas & a
     std::optional<OutputBlockColumns> out_cols;
     std::optional<Sizes> shuffled_key_sizes;
 
+    size_t rows_in_current_block = 0;
+
     auto init_out_cols = [&]()
     {
         out_cols = prepareOutputBlockColumns(params, aggregate_functions, getHeader(final), aggregates_pools, final, max_block_size);
@@ -2115,6 +2117,8 @@ Aggregator::convertToBlockImplNotFinal(Method & method, Table & data, Arenas & a
                 for (size_t i = 0; i < params.aggregates_size; ++i)
                     out_cols->aggregate_columns_data[i]->push_back(data.getNullKeyData() + offsets_of_aggregate_states[i]);
 
+                ++rows_in_current_block;
+
                 data.getNullKeyData() = nullptr;
                 data.hasNullKeyData() = false;
             }
@@ -2126,7 +2130,6 @@ Aggregator::convertToBlockImplNotFinal(Method & method, Table & data, Arenas & a
     // should be invoked at least once, because null data might be the only content of the `data`
     init_out_cols();
 
-    size_t rows_in_current_block = 0;
 
     data.forEachValue(
         [&](const auto & key, auto & mapped)