Merge pull request #15532 from ClickHouse/substitute_defaults_recursively

Fix defaults substitution for absent columns which depend on other defaults

programs/client/Client.cpp

@@ -1555,9 +1555,8 @@ private:
         BlockInputStreamPtr block_input = context.getInputFormat(
             current_format, buf, sample, insert_format_max_block_size);
 
-        const auto & column_defaults = columns_description.getDefaults();
+        if (columns_description.hasDefaults())
-        if (!column_defaults.empty())
+            block_input = std::make_shared<AddingDefaultsBlockInputStream>(block_input, columns_description, context);
-            block_input = std::make_shared<AddingDefaultsBlockInputStream>(block_input, column_defaults, context);
 
         BlockInputStreamPtr async_block_input = std::make_shared<AsynchronousBlockInputStream>(block_input);
 

src/DataStreams/AddingDefaultBlockOutputStream.cpp

@@ -7,7 +7,7 @@ namespace DB
 
 void AddingDefaultBlockOutputStream::write(const Block & block)
 {
-    output->write(addMissingDefaults(block, output_block.getNamesAndTypesList(), column_defaults, context));
+    output->write(addMissingDefaults(block, output_block.getNamesAndTypesList(), columns, context));
 }
 
 void AddingDefaultBlockOutputStream::flush()

src/DataStreams/AddingDefaultBlockOutputStream.h

@@ -2,7 +2,7 @@
 
 #include <DataStreams/IBlockOutputStream.h>
 #include <Columns/ColumnConst.h>
-#include <Storages/ColumnDefault.h>
+#include <Storages/ColumnsDescription.h>
 
 
 namespace DB
@@ -23,10 +23,10 @@ public:
         const BlockOutputStreamPtr & output_,
         const Block & header_,
         const Block & output_block_,
-        const ColumnDefaults & column_defaults_,
+        const ColumnsDescription & columns_,
         const Context & context_)
         : output(output_), header(header_), output_block(output_block_),
-          column_defaults(column_defaults_), context(context_)
+          columns(columns_), context(context_)
     {
     }
 
@@ -43,7 +43,7 @@ private:
     const Block header;
     /// Blocks after this stream should have this structure
     const Block output_block;
-    const ColumnDefaults column_defaults;
+    const ColumnsDescription columns;
     const Context & context;
 };
 

src/DataStreams/AddingDefaultsBlockInputStream.cpp

@@ -127,11 +127,13 @@ static MutableColumnPtr mixColumns(const ColumnWithTypeAndName & col_read,
 }
 
 
-AddingDefaultsBlockInputStream::AddingDefaultsBlockInputStream(const BlockInputStreamPtr & input,
+AddingDefaultsBlockInputStream::AddingDefaultsBlockInputStream(
-                                                               const ColumnDefaults & column_defaults_,
+    const BlockInputStreamPtr & input,
-                                                               const Context & context_)
+    const ColumnsDescription & columns_,
-    : column_defaults(column_defaults_),
+    const Context & context_)
-      context(context_)
+    : columns(columns_)
+    , column_defaults(columns.getDefaults())
+    , context(context_)
 {
     children.push_back(input);
     header = input->getHeader();
@@ -169,7 +171,7 @@ Block AddingDefaultsBlockInputStream::readImpl()
     if (!evaluate_block.columns())
         evaluate_block.insert({ColumnConst::create(ColumnUInt8::create(1, 0), res.rows()), std::make_shared<DataTypeUInt8>(), "_dummy"});
 
-    evaluateMissingDefaults(evaluate_block, header.getNamesAndTypesList(), column_defaults, context, false);
+    evaluateMissingDefaults(evaluate_block, header.getNamesAndTypesList(), columns, context, false);
 
     std::unordered_map<size_t, MutableColumnPtr> mixed_columns;
 

src/DataStreams/AddingDefaultsBlockInputStream.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include <DataStreams/IBlockInputStream.h>
-#include <Storages/ColumnDefault.h>
+#include <Storages/ColumnsDescription.h>
 
 
 namespace DB
@@ -15,7 +15,7 @@ class AddingDefaultsBlockInputStream : public IBlockInputStream
 public:
     AddingDefaultsBlockInputStream(
         const BlockInputStreamPtr & input,
-        const ColumnDefaults & column_defaults_,
+        const ColumnsDescription & columns_,
         const Context & context_);
 
     String getName() const override { return "AddingDefaults"; }
@@ -26,6 +26,7 @@ protected:
 
 private:
     Block header;
+    const ColumnsDescription columns;
     const ColumnDefaults column_defaults;
     const Context & context;
 };

src/DataStreams/InputStreamFromASTInsertQuery.cpp

@@ -64,9 +64,9 @@ InputStreamFromASTInsertQuery::InputStreamFromASTInsertQuery(
     {
         StoragePtr storage = DatabaseCatalog::instance().getTable(ast_insert_query->table_id, context);
         auto metadata_snapshot = storage->getInMemoryMetadataPtr();
-        auto column_defaults = metadata_snapshot->getColumns().getDefaults();
+        const auto & columns = metadata_snapshot->getColumns();
-        if (!column_defaults.empty())
+        if (columns.hasDefaults())
-            res_stream = std::make_shared<AddingDefaultsBlockInputStream>(res_stream, column_defaults, context);
+            res_stream = std::make_shared<AddingDefaultsBlockInputStream>(res_stream, columns, context);
     }
 }
 

src/DataStreams/PushingToViewsBlockOutputStream.cpp

@@ -1,4 +1,3 @@
-#include <DataStreams/AddingDefaultBlockOutputStream.h>
 #include <DataStreams/ConvertingBlockInputStream.h>
 #include <DataStreams/PushingToViewsBlockOutputStream.h>
 #include <DataStreams/SquashingBlockInputStream.h>

src/Interpreters/InterpreterInsertQuery.cpp

@@ -348,7 +348,7 @@ BlockIO InterpreterInsertQuery::execute()
             /// Actually we don't know structure of input blocks from query/table,
             /// because some clients break insertion protocol (columns != header)
             out = std::make_shared<AddingDefaultBlockOutputStream>(
-                out, query_sample_block, out->getHeader(), metadata_snapshot->getColumns().getDefaults(), context);
+                out, query_sample_block, out->getHeader(), metadata_snapshot->getColumns(), context);
 
             /// It's important to squash blocks as early as possible (before other transforms),
             ///  because other transforms may work inefficient if block size is small.

src/Interpreters/addMissingDefaults.cpp

@@ -6,16 +6,17 @@
 #include <Columns/ColumnArray.h>
 #include <Interpreters/inplaceBlockConversions.h>
 #include <Core/Block.h>
-#include <Storages/ColumnDefault.h>
+#include <Storages/ColumnsDescription.h>
 
 
 namespace DB
 {
 
-Block addMissingDefaults(const Block & block,
+Block addMissingDefaults(
-                         const NamesAndTypesList & required_columns,
+    const Block & block,
-                         const ColumnDefaults & column_defaults,
+    const NamesAndTypesList & required_columns,
-                         const Context & context)
+    const ColumnsDescription & columns,
+    const Context & context)
 {
     /// For missing columns of nested structure, you need to create not a column of empty arrays, but a column of arrays of correct lengths.
     /// First, remember the offset columns for all arrays in the block.
@@ -49,7 +50,7 @@ Block addMissingDefaults(const Block & block,
             continue;
         }
 
-        if (column_defaults.count(column.name))
+        if (columns.hasDefault(column.name))
             continue;
 
         String offsets_name = Nested::extractTableName(column.name);
@@ -72,8 +73,8 @@ Block addMissingDefaults(const Block & block,
         res.insert(ColumnWithTypeAndName(std::move(new_column), column.type, column.name));
     }
 
-    /// Computes explicitly specified values (in column_defaults) by default and materialized columns.
+    /// Computes explicitly specified values by default and materialized columns.
-    evaluateMissingDefaults(res, required_columns, column_defaults, context);
+    evaluateMissingDefaults(res, required_columns, columns, context);
     return res;
 }
 

src/Interpreters/addMissingDefaults.h

@@ -10,7 +10,7 @@ namespace DB
 class Block;
 class Context;
 class NamesAndTypesList;
-struct ColumnDefault;
+class ColumnsDescription;
 
 /** Adds three types of columns into block
   * 1. Columns, that are missed inside request, but present in table without defaults (missed columns)
@@ -21,7 +21,7 @@ struct ColumnDefault;
 Block addMissingDefaults(
     const Block & block,
     const NamesAndTypesList & required_columns,
-    const std::unordered_map<std::string, ColumnDefault> & column_defaults,
+    const ColumnsDescription & columns,
     const Context & context);
 
 }

src/Interpreters/inplaceBlockConversions.cpp

@@ -2,7 +2,6 @@
 
 #include <Core/Block.h>
 #include <Parsers/queryToString.h>
-#include <Storages/ColumnDefault.h>
 #include <Interpreters/TreeRewriter.h>
 #include <Interpreters/ExpressionAnalyzer.h>
 #include <Interpreters/ExpressionActions.h>
@@ -14,6 +13,8 @@
 #include <utility>
 #include <DataTypes/DataTypesNumber.h>
 #include <Interpreters/RequiredSourceColumnsVisitor.h>
+#include <Common/checkStackSize.h>
+#include <Storages/ColumnsDescription.h>
 
 
 namespace DB
@@ -22,46 +23,46 @@ namespace DB
 namespace
 {
 
-ASTPtr defaultRequiredExpressions(Block & block, const NamesAndTypesList & required_columns, const ColumnDefaults & column_defaults)
+/// Add all required expressions for missing columns calculation
+void addDefaultRequiredExpressionsRecursively(Block & block, const String & required_column, const ColumnsDescription & columns, ASTPtr default_expr_list_accum, NameSet & added_columns)
+{
+    checkStackSize();
+    if (block.has(required_column) || added_columns.count(required_column))
+        return;
+
+    auto column_default = columns.getDefault(required_column);
+
+    if (column_default)
+    {
+        /// expressions must be cloned to prevent modification by the ExpressionAnalyzer
+        auto column_default_expr = column_default->expression->clone();
+
+        /// Our default may depend on columns with default expr which not present in block
+        /// we have to add them to block too
+        RequiredSourceColumnsVisitor::Data columns_context;
+        RequiredSourceColumnsVisitor(columns_context).visit(column_default_expr);
+        NameSet required_columns_names = columns_context.requiredColumns();
+
+        auto cast_func = makeASTFunction("CAST", column_default_expr, std::make_shared<ASTLiteral>(columns.get(required_column).type->getName()));
+        default_expr_list_accum->children.emplace_back(setAlias(cast_func, required_column));
+        added_columns.emplace(required_column);
+
+        for (const auto & required_column_name : required_columns_names)
+            addDefaultRequiredExpressionsRecursively(block, required_column_name, columns, default_expr_list_accum, added_columns);
+    }
+}
+
+ASTPtr defaultRequiredExpressions(Block & block, const NamesAndTypesList & required_columns, const ColumnsDescription & columns)
 {
     ASTPtr default_expr_list = std::make_shared<ASTExpressionList>();
 
+    NameSet added_columns;
     for (const auto & column : required_columns)
-    {
+        addDefaultRequiredExpressionsRecursively(block, column.name, columns, default_expr_list, added_columns);
-        if (block.has(column.name))
-            continue;
-
-        const auto it = column_defaults.find(column.name);
-
-        if (it != column_defaults.end())
-        {
-            /// expressions must be cloned to prevent modification by the ExpressionAnalyzer
-            auto column_default_expr = it->second.expression->clone();
-
-            /// Our default may depend on columns with ALIAS as default expr which not present in block
-            /// we can easily add them from column_defaults struct
-            RequiredSourceColumnsVisitor::Data columns_context;
-            RequiredSourceColumnsVisitor(columns_context).visit(column_default_expr);
-            NameSet required_columns_names = columns_context.requiredColumns();
-
-            for (const auto & required_column_name : required_columns_names)
-            {
-                /// If we have such default column and it's alias than we should
-                /// add it into default_expression_list
-                if (auto rit = column_defaults.find(required_column_name);
-                    rit != column_defaults.end() && rit->second.kind == ColumnDefaultKind::Alias)
-                {
-                    default_expr_list->children.emplace_back(setAlias(rit->second.expression->clone(), required_column_name));
-                }
-            }
-
-            auto cast_func = makeASTFunction("CAST", column_default_expr, std::make_shared<ASTLiteral>(column.type->getName()));
-            default_expr_list->children.emplace_back(setAlias(cast_func, it->first));
-        }
-    }
 
     if (default_expr_list->children.empty())
         return nullptr;
+
     return default_expr_list;
 }
 
@@ -161,13 +162,13 @@ void performRequiredConversions(Block & block, const NamesAndTypesList & require
 
 void evaluateMissingDefaults(Block & block,
     const NamesAndTypesList & required_columns,
-    const ColumnDefaults & column_defaults,
+    const ColumnsDescription & columns,
     const Context & context, bool save_unneeded_columns)
 {
-    if (column_defaults.empty())
+    if (!columns.hasDefaults())
         return;
 
-    ASTPtr default_expr_list = defaultRequiredExpressions(block, required_columns, column_defaults);
+    ASTPtr default_expr_list = defaultRequiredExpressions(block, required_columns, columns);
     executeExpressionsOnBlock(block, default_expr_list, save_unneeded_columns, required_columns, context);
 }
 

src/Interpreters/inplaceBlockConversions.h

@@ -10,13 +10,13 @@ namespace DB
 class Block;
 class Context;
 class NamesAndTypesList;
-struct ColumnDefault;
+class ColumnsDescription;
 
 /// Adds missing defaults to block according to required_columns
-/// using column_defaults map
+/// using columns description
 void evaluateMissingDefaults(Block & block,
     const NamesAndTypesList & required_columns,
-    const std::unordered_map<std::string, ColumnDefault> & column_defaults,
+    const ColumnsDescription & columns,
     const Context & context, bool save_unneeded_columns = true);
 
 /// Tries to convert columns in block to required_columns

src/Processors/Transforms/AddingMissedTransform.cpp

@@ -8,10 +8,10 @@ namespace DB
 AddingMissedTransform::AddingMissedTransform(
     Block header_,
     Block result_header_,
-    const ColumnDefaults & column_defaults_,
+    const ColumnsDescription & columns_,
     const Context & context_)
     : ISimpleTransform(std::move(header_), std::move(result_header_), false)
-    , column_defaults(column_defaults_), context(context_)
+    , columns(columns_), context(context_)
 {
 }
 
@@ -20,7 +20,7 @@ void AddingMissedTransform::transform(Chunk & chunk)
     auto num_rows = chunk.getNumRows();
     Block src = getInputPort().getHeader().cloneWithColumns(chunk.detachColumns());
 
-    auto res = addMissingDefaults(src, getOutputPort().getHeader().getNamesAndTypesList(), column_defaults, context);
+    auto res = addMissingDefaults(src, getOutputPort().getHeader().getNamesAndTypesList(), columns, context);
     chunk.setColumns(res.getColumns(), num_rows);
 }
 

src/Processors/Transforms/AddingMissedTransform.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include <Processors/ISimpleTransform.h>
-#include <Storages/ColumnDefault.h>
+#include <Storages/ColumnsDescription.h>
 
 
 namespace DB
@@ -20,7 +20,7 @@ public:
     AddingMissedTransform(
         Block header_,
         Block result_header_,
-        const ColumnDefaults & column_defaults_,
+        const ColumnsDescription & columns_,
         const Context & context_);
 
     String getName() const override { return "AddingMissed"; }
@@ -28,7 +28,7 @@ public:
 private:
     void transform(Chunk &) override;
 
-    const ColumnDefaults column_defaults;
+    const ColumnsDescription columns;
     const Context & context;
 };
 

src/Storages/ColumnsDescription.cpp

@@ -378,6 +378,14 @@ bool ColumnsDescription::hasPhysical(const String & column_name) const
 }
 
 
+bool ColumnsDescription::hasDefaults() const
+{
+    for (const auto & column : columns)
+        if (column.default_desc.expression)
+            return true;
+    return false;
+}
+
 ColumnDefaults ColumnsDescription::getDefaults() const
 {
     ColumnDefaults ret;

src/Storages/ColumnsDescription.h

@@ -109,6 +109,7 @@ public:
 
     ColumnDefaults getDefaults() const; /// TODO: remove
     bool hasDefault(const String & column_name) const;
+    bool hasDefaults() const;
     std::optional<ColumnDefault> getDefault(const String & column_name) const;
 
     /// Does column has non default specified compression codec

src/Storages/MergeTree/IMergeTreeReader.cpp

@@ -180,7 +180,7 @@ void IMergeTreeReader::evaluateMissingDefaults(Block additional_columns, Columns
             additional_columns.insert({res_columns[pos], name_and_type->type, name_and_type->name});
         }
 
-        DB::evaluateMissingDefaults(additional_columns, columns, metadata_snapshot->getColumns().getDefaults(), storage.global_context);
+        DB::evaluateMissingDefaults(additional_columns, columns, metadata_snapshot->getColumns(), storage.global_context);
 
         /// Move columns from block.
         name_and_type = columns.begin();

src/Storages/StorageBuffer.cpp

@@ -224,7 +224,7 @@ Pipe StorageBuffer::read(
                 pipe_from_dst.addSimpleTransform([&](const Block & stream_header)
                 {
                     return std::make_shared<AddingMissedTransform>(stream_header, header_after_adding_defaults,
-                        metadata_snapshot->getColumns().getDefaults(), context);
+                        metadata_snapshot->getColumns(), context);
                 });
 
                 pipe_from_dst.addSimpleTransform([&](const Block & stream_header)

src/Storages/StorageFile.cpp

@@ -234,12 +234,12 @@ public:
         const Context & context_,
         UInt64 max_block_size_,
         FilesInfoPtr files_info_,
-        ColumnDefaults column_defaults_)
+        ColumnsDescription columns_description_)
         : SourceWithProgress(getHeader(metadata_snapshot_, files_info_->need_path_column, files_info_->need_file_column))
         , storage(std::move(storage_))
         , metadata_snapshot(metadata_snapshot_)
         , files_info(std::move(files_info_))
-        , column_defaults(std::move(column_defaults_))
+        , columns_description(std::move(columns_description_))
         , context(context_)
         , max_block_size(max_block_size_)
     {
@@ -314,8 +314,8 @@ public:
                 reader = FormatFactory::instance().getInput(
                         storage->format_name, *read_buf, metadata_snapshot->getSampleBlock(), context, max_block_size);
 
-                if (!column_defaults.empty())
+                if (columns_description.hasDefaults())
-                    reader = std::make_shared<AddingDefaultsBlockInputStream>(reader, column_defaults, context);
+                    reader = std::make_shared<AddingDefaultsBlockInputStream>(reader, columns_description, context);
 
                 reader->readPrefix();
             }
@@ -366,7 +366,7 @@ private:
     std::unique_ptr<ReadBuffer> read_buf;
     BlockInputStreamPtr reader;
 
-    ColumnDefaults column_defaults;
+    ColumnsDescription columns_description;
 
     const Context & context;    /// TODO Untangle potential issues with context lifetime.
     UInt64 max_block_size;
@@ -417,7 +417,7 @@ Pipe StorageFile::read(
 
     for (size_t i = 0; i < num_streams; ++i)
         pipes.emplace_back(std::make_shared<StorageFileSource>(
-                this_ptr, metadata_snapshot, context, max_block_size, files_info, metadata_snapshot->getColumns().getDefaults()));
+                this_ptr, metadata_snapshot, context, max_block_size, files_info, metadata_snapshot->getColumns()));
 
     return Pipe::unitePipes(std::move(pipes));
 }

src/Storages/StorageS3.cpp

@@ -71,7 +71,7 @@ namespace
             String name_,
             const Block & sample_block,
             const Context & context,
-            const ColumnDefaults & column_defaults,
+            const ColumnsDescription & columns,
             UInt64 max_block_size,
             const CompressionMethod compression_method,
             const std::shared_ptr<Aws::S3::S3Client> & client,
@@ -86,8 +86,8 @@ namespace
             read_buf = wrapReadBufferWithCompressionMethod(std::make_unique<ReadBufferFromS3>(client, bucket, key), compression_method);
             reader = FormatFactory::instance().getInput(format, *read_buf, sample_block, context, max_block_size);
 
-            if (!column_defaults.empty())
+            if (columns.hasDefaults())
-                reader = std::make_shared<AddingDefaultsBlockInputStream>(reader, column_defaults, context);
+                reader = std::make_shared<AddingDefaultsBlockInputStream>(reader, columns, context);
         }
 
         String getName() const override
@@ -312,7 +312,7 @@ Pipe StorageS3::read(
             getName(),
             metadata_snapshot->getSampleBlock(),
             context,
-            metadata_snapshot->getColumns().getDefaults(),
+            metadata_snapshot->getColumns(),
             max_block_size,
             chooseCompressionMethod(uri.endpoint, compression_method),
             client,

src/Storages/StorageURL.cpp

@@ -61,7 +61,7 @@ namespace
             String name_,
             const Block & sample_block,
             const Context & context,
-            const ColumnDefaults & column_defaults,
+            const ColumnsDescription & columns,
             UInt64 max_block_size,
             const ConnectionTimeouts & timeouts,
             const CompressionMethod compression_method)
@@ -81,7 +81,7 @@ namespace
                 compression_method);
 
             reader = FormatFactory::instance().getInput(format, *read_buf, sample_block, context, max_block_size);
-            reader = std::make_shared<AddingDefaultsBlockInputStream>(reader, column_defaults, context);
+            reader = std::make_shared<AddingDefaultsBlockInputStream>(reader, columns, context);
         }
 
         String getName() const override
@@ -201,7 +201,7 @@ Pipe IStorageURLBase::read(
         getName(),
         getHeaderBlock(column_names, metadata_snapshot),
         context,
-        metadata_snapshot->getColumns().getDefaults(),
+        metadata_snapshot->getColumns(),
         max_block_size,
         ConnectionTimeouts::getHTTPTimeouts(context),
         chooseCompressionMethod(request_uri.getPath(), compression_method)));

tests/queries/0_stateless/01513_defaults_on_defaults_no_column.reference

@@ -0,0 +1,7 @@
+1
+1
+1
+1
+1	[]	[]	[]	0
+CREATE TABLE default.defaults_on_defaults\n(\n    `key` UInt64,\n    `Arr.C1` Array(UInt32) DEFAULT emptyArrayUInt32(),\n    `Arr.C2` Array(UInt32) DEFAULT arrayResize(emptyArrayUInt32(), length(Arr.C1)),\n    `Arr.C3` Array(UInt32) ALIAS arrayResize(emptyArrayUInt32(), length(Arr.C2)),\n    `Arr.C4` Array(UInt32) DEFAULT arrayResize(emptyArrayUInt32(), length(Arr.C3)),\n    `ArrLen` UInt64 DEFAULT length(Arr.C4)\n)\nENGINE = MergeTree()\nORDER BY tuple()\nSETTINGS index_granularity = 8192
+1

tests/queries/0_stateless/01513_defaults_on_defaults_no_column.sql

@@ -0,0 +1,36 @@
+DROP TABLE IF EXISTS defaults_on_defaults;
+CREATE TABLE defaults_on_defaults (
+    key UInt64
+)
+ENGINE = MergeTree()
+ORDER BY tuple();
+
+INSERT INTO defaults_on_defaults values (1);
+
+ALTER TABLE defaults_on_defaults ADD COLUMN `Arr.C1` Array(UInt32) DEFAULT emptyArrayUInt32();
+
+ALTER TABLE defaults_on_defaults ADD COLUMN `Arr.C2` Array(UInt32) DEFAULT arrayResize(emptyArrayUInt32(), length(Arr.C1));
+
+ALTER TABLE defaults_on_defaults ADD COLUMN `Arr.C3` Array(UInt32) ALIAS arrayResize(emptyArrayUInt32(), length(Arr.C2));
+
+SELECT 1 from defaults_on_defaults where length(`Arr.C2`) = 0;
+
+SELECT 1 from defaults_on_defaults where length(`Arr.C3`) = 0;
+
+ALTER TABLE defaults_on_defaults ADD COLUMN `Arr.C4` Array(UInt32) DEFAULT arrayResize(emptyArrayUInt32(), length(Arr.C3));
+
+SELECT 1 from defaults_on_defaults where length(`Arr.C4`) = 0;
+
+ALTER TABLE defaults_on_defaults ADD COLUMN `ArrLen` UInt64 DEFAULT length(Arr.C4);
+
+SELECT 1 from defaults_on_defaults where ArrLen = 0;
+
+SELECT * from defaults_on_defaults where ArrLen = 0;
+
+SHOW CREATE TABLE defaults_on_defaults;
+
+OPTIMIZE TABLE defaults_on_defaults FINAL;
+
+SELECT 1 from defaults_on_defaults where length(`Arr.C4`) = 0;
+
+DROP TABLE IF EXISTS defaults_on_defaults;