[feature](nereids)support unnest function

be/src/pipeline/exec/table_function_operator.h

@@ -56,7 +56,8 @@ class TableFunctionLocalState MOCK_REMOVE(final) : public PipelineXLocalState<>
 
     MOCK_FUNCTION Status _clone_table_function(RuntimeState* state);
 
-    void _copy_output_slots(std::vector<vectorized::MutableColumnPtr>& columns);
+    void _copy_output_slots(std::vector<vectorized::MutableColumnPtr>& columns,
+                            const TableFunctionOperatorX& p);
     bool _roll_table_functions(int last_eos_idx);
     // return:
     //  0: all fns are eos
@@ -65,12 +66,19 @@ class TableFunctionLocalState MOCK_REMOVE(final) : public PipelineXLocalState<>
     int _find_last_fn_eos_idx() const;
     bool _is_inner_and_empty();
 
+    Status _get_expanded_block_for_outer_conjuncts(RuntimeState* state,
+                                                   vectorized::Block* output_block, bool* eos);
+
     std::vector<vectorized::TableFunction*> _fns;
     vectorized::VExprContextSPtrs _vfn_ctxs;
+    vectorized::VExprContextSPtrs _expand_conjuncts_ctxs;
+    // for table function with outer conjuncts, need to handle those child rows which all expanded rows are filtered out
+    bool _need_to_handle_outer_conjuncts = false;
     int64_t _cur_child_offset = -1;
     std::unique_ptr<vectorized::Block> _child_block;
     int _current_row_insert_times = 0;
     bool _child_eos = false;
+    DorisVector<bool> _child_rows_has_output;
 
     RuntimeProfile::Counter* _init_function_timer = nullptr;
     RuntimeProfile::Counter* _process_rows_timer = nullptr;
@@ -110,6 +118,7 @@ class TableFunctionOperatorX MOCK_REMOVE(final)
             SCOPED_TIMER(local_state._init_function_timer);
             RETURN_IF_ERROR(fn->process_init(input_block, state));
         }
+        local_state._child_rows_has_output.resize(input_block->rows(), false);
         local_state.process_next_child_row();
         return Status::OK();
     }
@@ -150,6 +159,7 @@ class TableFunctionOperatorX MOCK_REMOVE(final)
     std::vector<SlotDescriptor*> _output_slots;
 
     vectorized::VExprContextSPtrs _vfn_ctxs;
+    vectorized::VExprContextSPtrs _expand_conjuncts_ctxs;
 
     std::vector<vectorized::TableFunction*> _fns;
     int _fn_num = 0;