dbms: Server: Feature development. [#METR-19266]

dbms/include/DB/Functions/FunctionsMiscellaneous.h

@@ -171,6 +171,11 @@ public:
 		return name;
 	}
 
+	bool hasSpecialSupportForNullValues() const override
+	{
+		return true;
+	}
+
 	/// Получить тип результата по типам аргументов. Если функция неприменима для данных аргументов - кинуть исключение.
 	DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
 	{

dbms/src/DataStreams/PrettyBlockOutputStream.cpp

@@ -2,8 +2,9 @@
 #include <unistd.h>
 
 #include <DB/Functions/FunctionsMiscellaneous.h>
-
 #include <DB/DataStreams/PrettyBlockOutputStream.h>
+#include <DB/Columns/ColumnNullable.h>
+#include <DB/DataTypes/NullSymbol.h>
 
 
 namespace DB
@@ -46,20 +47,39 @@ void PrettyBlockOutputStream::calculateWidths(Block & block, Widths_t & max_widt
 
 		column.column = block.getByPosition(i + columns).column;
 
-		if (const ColumnUInt64 * col = typeid_cast<const ColumnUInt64 *>(&*column.column))
+		IColumn * observed_col;
+		if (column.column.get()->isNullable())
+		{
+			ColumnNullable & nullable_col = static_cast<ColumnNullable &>(*(column.column.get()));
+			observed_col = nullable_col.getNestedColumn().get();
+		}
+		else
+			observed_col = column.column.get();
+
+		if (const ColumnUInt64 * col = typeid_cast<const ColumnUInt64 *>(observed_col))
 		{
 			const ColumnUInt64::Container_t & res = col->getData();
 			for (size_t j = 0; j < rows; ++j)
-				if (res[j] > max_widths[i])
+			{
-					max_widths[i] = res[j];
+				Field f = (*(block.getByPosition(columns + i).column))[j];
+
+				size_t cur_width;
+				if (f.isNull())
+					cur_width = NullSymbol::Escaped::length;
+				else
+					cur_width = res[j];
+
+				if (cur_width > max_widths[i])
+					max_widths[i] = cur_width;
+			}
 		}
-		else if (const ColumnConstUInt64 * col = typeid_cast<const ColumnConstUInt64 *>(&*column.column))
+		else if (const ColumnConstUInt64 * col = typeid_cast<const ColumnConstUInt64 *>(observed_col))
 		{
 			UInt64 res = col->getData();
 			max_widths[i] = res;
 		}
 		else
-			throw Exception("Illegal column " + column.column->getName()
+			throw Exception("Illegal column " + observed_col->getName()
 				+ " of result of function " + visible_width_func.getName(),
 				ErrorCodes::ILLEGAL_COLUMN);
 

dbms/src/Functions/FunctionsMiscellaneous.cpp

@@ -4,6 +4,7 @@
 #include <DB/Functions/FunctionsArithmetic.h>
 #include <DB/Functions/FunctionsMiscellaneous.h>
 #include <DB/DataTypes/DataTypeEnum.h>
+#include <DB/Columns/ColumnNull.h>
 #include <ext/enumerate.hpp>
 
 
@@ -368,6 +369,8 @@ void FunctionVisibleWidth::executeImpl(Block & block, const ColumnNumbers & argu
 		  */
 		block.getByPosition(result).column = std::make_shared<ColumnConstUInt64>(rows, 10);
 	}
+	else if (typeid_cast<const ColumnNull *>(&*column) != nullptr)
+		block.getByPosition(result).column = std::make_shared<ColumnConstUInt64>(rows, strlen_constexpr("NULL"));
 	else
 	   throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
 			+ " of argument of function " + getName(),