Make use_mysql_types_in_show_columns affect only SHOW COLUMNS

src/DataTypes/DataTypeAggregateFunction.h

@@ -45,7 +45,6 @@ public:
     String doGetName() const override;
     String getNameWithoutVersion() const;
     const char * getFamilyName() const override { return "AggregateFunction"; }
-    String getSQLCompatibleName() const override { return "TEXT"; }
     TypeIndex getTypeId() const override { return TypeIndex::AggregateFunction; }
 
     Array getParameters() const { return parameters; }

src/DataTypes/DataTypeArray.h

@@ -35,10 +35,6 @@ public:
     {
         return "Array";
     }
-    String getSQLCompatibleName() const override
-    {
-        return "TEXT";
-    }
 
     bool canBeInsideNullable() const override
     {

src/DataTypes/DataTypeDate.h

@@ -13,7 +13,6 @@ public:
 
     TypeIndex getTypeId() const override { return TypeIndex::Date; }
     const char * getFamilyName() const override { return family_name; }
-    String getSQLCompatibleName() const override { return "DATE"; }
 
     bool canBeUsedAsVersion() const override { return true; }
     bool canBeInsideNullable() const override { return true; }

src/DataTypes/DataTypeDate32.h

@@ -13,7 +13,6 @@ public:
 
     TypeIndex getTypeId() const override { return TypeIndex::Date32; }
     const char * getFamilyName() const override { return family_name; }
-    String getSQLCompatibleName() const override { return "DATE"; }
 
     Field getDefault() const override
     {

src/DataTypes/DataTypeDateTime.h

@@ -38,7 +38,6 @@ public:
     static constexpr auto family_name = "DateTime";
 
     const char * getFamilyName() const override { return family_name; }
-    String getSQLCompatibleName() const override { return "DATETIME"; }
     String doGetName() const override;
     TypeIndex getTypeId() const override { return TypeIndex::DateTime; }
 

src/DataTypes/DataTypeDateTime64.h

@@ -28,7 +28,6 @@ public:
     DataTypeDateTime64(UInt32 scale_, const TimezoneMixin & time_zone_info);
 
     const char * getFamilyName() const override { return family_name; }
-    String getSQLCompatibleName() const override { return "DATETIME"; }
     std::string doGetName() const override;
     TypeIndex getTypeId() const override { return type_id; }
 

src/DataTypes/DataTypeEnum.cpp

@@ -36,30 +36,6 @@ const char * DataTypeEnum<Type>::getFamilyName() const
     return EnumName<FieldType>::value;
 }
 
-template <typename Type>
-std::string DataTypeEnum<Type>::generateMySQLName(const Values & values)
-{
-    WriteBufferFromOwnString out;
-
-    writeString("ENUM", out);
-    writeChar('(', out);
-
-    auto first = true;
-    for (const auto & name_and_value : values)
-    {
-        if (!first)
-            writeString(", ", out);
-
-        first = false;
-
-        writeQuotedString(name_and_value.first, out);
-    }
-
-    writeChar(')', out);
-
-    return out.str();
-}
-
 template <typename Type>
 std::string DataTypeEnum<Type>::generateName(const Values & values)
 {

src/DataTypes/DataTypeEnum.h

@@ -46,14 +46,12 @@ public:
 private:
     std::string type_name;
     static std::string generateName(const Values & values);
-    static std::string generateMySQLName(const Values & values);
 
 public:
     explicit DataTypeEnum(const Values & values_);
 
     std::string doGetName() const override { return type_name; }
     const char * getFamilyName() const override;
-    String getSQLCompatibleName() const override { return generateMySQLName(this->getValues()); }
 
     TypeIndex getTypeId() const override { return type_id; }
 

src/DataTypes/DataTypeFixedString.h

@@ -42,8 +42,6 @@ public:
     TypeIndex getTypeId() const override { return type_id; }
 
     const char * getFamilyName() const override { return "FixedString"; }
-    /// Use TEXT for compatibility with MySQL to allow arbitrary bytes.
-    String getSQLCompatibleName() const override { return "TEXT"; }
 
     size_t getN() const
     {

src/DataTypes/DataTypeFunction.h

@@ -24,7 +24,6 @@ public:
 
     std::string doGetName() const override;
     const char * getFamilyName() const override { return "Function"; }
-    String getSQLCompatibleName() const override { return "TEXT"; }
     TypeIndex getTypeId() const override { return TypeIndex::Function; }
 
     const DataTypes & getArgumentTypes() const

src/DataTypes/DataTypeIPv4andIPv6.h

@@ -19,7 +19,6 @@ public:
     static constexpr auto type_id = TypeToTypeIndex<IPv4>;
 
     const char * getFamilyName() const override { return TypeName<IPv4>.data(); }
-    String getSQLCompatibleName() const override { return "TEXT"; }
 
     TypeIndex getTypeId() const override { return type_id; }
 
@@ -61,7 +60,6 @@ public:
     static constexpr auto type_id = TypeToTypeIndex<IPv6>;
 
     const char * getFamilyName() const override { return TypeName<IPv6>.data(); }
-    String getSQLCompatibleName() const override { return "TEXT"; }
 
     TypeIndex getTypeId() const override { return type_id; }
 

src/DataTypes/DataTypeInterval.h

@@ -27,7 +27,6 @@ public:
     SerializationPtr doGetDefaultSerialization() const override;
     std::string doGetName() const override { return fmt::format("Interval{}", kind.toString()); }
     const char * getFamilyName() const override { return "Interval"; }
-    String getSQLCompatibleName() const override { return "TEXT"; }
     TypeIndex getTypeId() const override { return TypeIndex::Interval; }
 
     bool equals(const IDataType & rhs) const override;

src/DataTypes/DataTypeLowCardinality.h

@@ -23,7 +23,6 @@ public:
         return "LowCardinality(" + dictionary_type->getName() + ")";
     }
     const char * getFamilyName() const override { return "LowCardinality"; }
-    String getSQLCompatibleName() const override { return dictionary_type->getSQLCompatibleName(); }
 
     TypeIndex getTypeId() const override { return TypeIndex::LowCardinality; }
 

src/DataTypes/DataTypeMap.h

@@ -31,7 +31,6 @@ public:
     std::string doGetName() const override;
     std::string doGetPrettyName(size_t indent) const override;
     const char * getFamilyName() const override { return "Map"; }
-    String getSQLCompatibleName() const override { return "JSON"; }
 
     bool canBeInsideNullable() const override { return false; }
 

src/DataTypes/DataTypeNothing.h

@@ -16,7 +16,6 @@ public:
     static constexpr bool is_parametric = false;
 
     const char * getFamilyName() const override { return "Nothing"; }
-    String getSQLCompatibleName() const override { return "TEXT"; }
 
     TypeIndex getTypeId() const override { return TypeIndex::Nothing; }
 

src/DataTypes/DataTypeNullable.h

@@ -16,7 +16,6 @@ public:
     explicit DataTypeNullable(const DataTypePtr & nested_data_type_);
     std::string doGetName() const override { return "Nullable(" + nested_data_type->getName() + ")"; }
     const char * getFamilyName() const override { return "Nullable"; }
-    String getSQLCompatibleName() const override { return nested_data_type->getSQLCompatibleName(); }
     TypeIndex getTypeId() const override { return TypeIndex::Nullable; }
 
     MutableColumnPtr createColumn() const override;

src/DataTypes/DataTypeNumberBase.cpp

@@ -11,34 +11,6 @@ Field DataTypeNumberBase<T>::getDefault() const
 {
     return NearestFieldType<FieldType>();
 }
-template <typename T>
-String DataTypeNumberBase<T>::getSQLCompatibleName() const
-{
-    if constexpr (std::is_same_v<T, Int8>)
-        return "TINYINT";
-    else if constexpr (std::is_same_v<T, Int16>)
-        return "SMALLINT";
-    else if constexpr (std::is_same_v<T, Int32>)
-        return "INTEGER";
-    else if constexpr (std::is_same_v<T, Int64>)
-        return "BIGINT";
-    else if constexpr (std::is_same_v<T, UInt8>)
-        return "TINYINT UNSIGNED";
-    else if constexpr (std::is_same_v<T, UInt16>)
-        return "SMALLINT UNSIGNED";
-    else if constexpr (std::is_same_v<T, UInt32>)
-        return "INTEGER UNSIGNED";
-    else if constexpr (std::is_same_v<T, UInt64>)
-        return "BIGINT UNSIGNED";
-    else if constexpr (std::is_same_v<T, Float32>)
-        return "FLOAT";
-    else if constexpr (std::is_same_v<T, Float64>)
-        return "DOUBLE";
-    /// Unsupported types are converted to TEXT
-    else
-        return "TEXT";
-}
-
 template <typename T>
 MutableColumnPtr DataTypeNumberBase<T>::createColumn() const
 {

src/DataTypes/DataTypeNumberBase.h

@@ -25,7 +25,6 @@ public:
     using ColumnType = ColumnVector<T>;
 
     const char * getFamilyName() const override { return TypeName<T>.data(); }
-    String getSQLCompatibleName() const override;
     TypeIndex getTypeId() const override { return TypeToTypeIndex<T>; }
 
     Field getDefault() const override;

src/DataTypes/DataTypeObject.h

@@ -23,7 +23,6 @@ public:
     DataTypeObject(const String & schema_format_, bool is_nullable_);
 
     const char * getFamilyName() const override { return "Object"; }
-    String getSQLCompatibleName() const override { return "JSON"; }
     String doGetName() const override;
     TypeIndex getTypeId() const override { return TypeIndex::Object; }
 

src/DataTypes/DataTypeSet.h

@@ -15,7 +15,6 @@ class DataTypeSet final : public IDataTypeDummy
 public:
     static constexpr bool is_parametric = true;
     const char * getFamilyName() const override { return "Set"; }
-    String getSQLCompatibleName() const override { return "TEXT"; }
 
     TypeIndex getTypeId() const override { return TypeIndex::Set; }
     bool equals(const IDataType & rhs) const override { return typeid(rhs) == typeid(*this); }

src/DataTypes/DataTypeString.h

@@ -21,8 +21,6 @@ public:
         return "String";
     }
 
-    String getSQLCompatibleName() const override { return "BLOB"; }
-
     TypeIndex getTypeId() const override { return type_id; }
 
     MutableColumnPtr createColumn() const override;

src/DataTypes/DataTypeTuple.h

@@ -34,7 +34,6 @@ public:
     std::string doGetName() const override;
     std::string doGetPrettyName(size_t indent) const override;
     const char * getFamilyName() const override { return "Tuple"; }
-    String getSQLCompatibleName() const override { return "JSON"; }
 
     bool canBeInsideNullable() const override { return false; }
     bool supportsSparseSerialization() const override { return true; }

src/DataTypes/DataTypeUUID.h

@@ -18,7 +18,6 @@ public:
     static constexpr auto type_id = TypeIndex::UUID;
 
     const char * getFamilyName() const override { return "UUID"; }
-    String getSQLCompatibleName() const override { return "CHAR"; }
 
     TypeIndex getTypeId() const override { return type_id; }
 

src/DataTypes/DataTypesDecimal.cpp

@@ -28,18 +28,6 @@ std::string DataTypeDecimal<T>::doGetName() const
     return fmt::format("Decimal({}, {})", this->precision, this->scale);
 }
 
-template <is_decimal T>
-std::string DataTypeDecimal<T>::getSQLCompatibleName() const
-{
-    /// See https://dev.mysql.com/doc/refman/8.0/en/precision-math-decimal-characteristics.html
-    /// DECIMAL(M,D)
-    /// M is the maximum number of digits (the precision). It has a range of 1 to 65.
-    /// D is the number of digits to the right of the decimal point (the scale). It has a range of 0 to 30 and must be no larger than M.
-    if (this->precision > 65 || this->scale > 30)
-        return "TEXT";
-    return fmt::format("DECIMAL({}, {})", this->precision, this->scale);
-}
-
 template <is_decimal T>
 bool DataTypeDecimal<T>::equals(const IDataType & rhs) const
 {

src/DataTypes/DataTypesDecimal.h

@@ -39,7 +39,6 @@ public:
     static constexpr auto family_name = "Decimal";
 
     const char * getFamilyName() const override { return family_name; }
-    String getSQLCompatibleName() const override;
 
     std::string doGetName() const override;
     TypeIndex getTypeId() const override { return TypeToTypeIndex<T>; }

src/DataTypes/IDataType.h

@@ -83,8 +83,6 @@ public:
 
     /// Name of data type family (example: FixedString, Array).
     virtual const char * getFamilyName() const = 0;
-    /// Name of corresponding data type in MySQL (exampe: Bigint, Blob, etc)
-    virtual String getSQLCompatibleName() const = 0;
 
     /// Data type id. It's used for runtime type checks.
     virtual TypeIndex getTypeId() const = 0;

src/Formats/SchemaInferenceUtils.cpp

@@ -83,11 +83,6 @@ namespace
         String doGetName() const override { return finalize()->getName(); }
         TypeIndex getTypeId() const override { return TypeIndex::JSONPaths; }
 
-        String getSQLCompatibleName() const override
-        {
-            throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Method getSQLCompatibleName is not implemented for JSONObjectForInference type");
-        }
-
         bool isParametric() const override
         {
             throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Method isParametric is not implemented for JSONObjectForInference type");

src/Interpreters/InterpreterShowColumnsQuery.cpp

@@ -24,6 +24,8 @@ String InterpreterShowColumnsQuery::getRewrittenQuery()
 {
     const auto & query = query_ptr->as<ASTShowColumnsQuery &>();
 
+    [[maybe_unused]] const bool use_mysql_types = getContext()->getSettingsRef().use_mysql_types_in_show_columns;
+
     WriteBufferFromOwnString buf_database;
     String resolved_database = getContext()->resolveDatabase(query.database);
     writeEscapedString(resolved_database, buf_database);
@@ -33,18 +35,64 @@ String InterpreterShowColumnsQuery::getRewrittenQuery()
     writeEscapedString(query.table, buf_table);
     String table = buf_table.str();
 
-    String rewritten_query = R"(
+    String rewritten_query;
+    if (use_mysql_types)
+        /// Cheapskate mapping from native to MySQL types, see https://dev.mysql.com/doc/refman/8.0/en/data-types.html
+        /// Known issues:
+        /// - Enums are translated to TEXT
+        rewritten_query += R"(
+WITH map(
+        'Int8',       'TINYINT',
+        'Int16',      'SMALLINT',
+        'Int32',      'INTEGER',
+        'Int64',      'BIGINT',
+        'UInt8',      'TINYINT UNSIGNED',
+        'UInt16',     'SMALLINT UNSIGNED',
+        'UInt32',     'INTEGER UNSIGNED',
+        'UInt64',     'BIGINT UNSIGNED',
+        'Float32',    'FLOAT',
+        'Float64',    'DOUBLE',
+        'String',     'BLOB',
+        'UUID',       'CHAR',
+        'Bool',       'TINYINT',
+        'Date',       'DATE',
+        'Date32',     'DATE',
+        'DateTime',   'DATETIME',
+        'DateTime64', 'DATETIME',
+        'Map',        'JSON',
+        'Tuple',      'JSON',
+        'Object',     'JSON') AS native_to_mysql_mapping,
+    splitByRegexp('\(|\)', type) AS split,
+    multiIf(startsWith(type, 'LowCardinality(Nullable'), split[3],
+             startsWith(type, 'LowCardinality'), split[2],
+             startsWith(type, 'Nullable'), split[2],
+             split[1]) AS inner_type,
+     if(length(split) > 1, splitByString(', ', split[2]), []) AS decimal_scale_and_precision,
+     multiIf(inner_type = 'Decimal' AND toInt8(decimal_scale_and_precision[1]) <= 65 AND toInt8(decimal_scale_and_precision[2]) <= 30, concat('DECIMAL(', decimal_scale_and_precision[1], ', ', decimal_scale_and_precision[2], ')'),
+             mapContains(native_to_mysql_mapping, inner_type) = true, native_to_mysql_mapping[inner_type],
+             'TEXT') AS mysql_type
+        )";
+
+    rewritten_query += R"(
 SELECT
     name AS field,
+    )";
+
+    if (use_mysql_types)
+        rewritten_query += R"(
+    mysql_type AS type,
+        )";
+    else
+        rewritten_query += R"(
     type AS type,
-    if (startsWith(type, 'Nullable'), 'YES', 'NO') AS `null`,
+        )";
+
+    rewritten_query += R"(
+    multiIf(startsWith(type, 'Nullable('), 'YES', startsWith(type, 'LowCardinality(Nullable('), 'YES', 'NO') AS `null`,
     trim(concatWithSeparator(' ', if (is_in_primary_key, 'PRI', ''), if (is_in_sorting_key, 'SOR', ''))) AS key,
     if (default_kind IN ('ALIAS', 'DEFAULT', 'MATERIALIZED'), default_expression, NULL) AS default,
     '' AS extra )";
 
-    // Known issue: Field 'null' is wrong for types like 'LowCardinality(Nullable(String))'. Can't simply replace 'startsWith' by
-    // `hasSubsequence` as that would return `true` for non-nullable types such as `Tuple(Nullable(String), String)`...
-
     // TODO Interpret query.extended. It is supposed to show internal/virtual columns. Need to fetch virtual column names, see
     // IStorage::getVirtuals(). We can't easily do that via SQL.
 

src/Storages/System/StorageSystemColumns.cpp

@@ -76,7 +76,6 @@ public:
         , columns_mask(std::move(columns_mask_)), max_block_size(max_block_size_)
         , databases(std::move(databases_)), tables(std::move(tables_)), storages(std::move(storages_))
         , client_info_interface(context->getClientInfo().interface)
-        , use_mysql_types(context->getSettingsRef().use_mysql_types_in_show_columns)
         , total_tables(tables->size()), access(context->getAccess())
         , query_id(context->getCurrentQueryId()), lock_acquire_timeout(context->getSettingsRef().lock_acquire_timeout)
     {
@@ -149,7 +148,7 @@ protected:
                 if (columns_mask[src_index++])
                     res_columns[res_index++]->insert(column.name);
                 if (columns_mask[src_index++])
-                    res_columns[res_index++]->insert(use_mysql_types ? (column.type->getSQLCompatibleName()) : (column.type->getName()));
+                    res_columns[res_index++]->insert(column.type->getName());
                 if (columns_mask[src_index++])
                     res_columns[res_index++]->insert(position);
 
@@ -285,7 +284,6 @@ private:
     ColumnPtr tables;
     Storages storages;
     ClientInfo::Interface client_info_interface;
-    bool use_mysql_types;
     size_t db_table_num = 0;
     size_t total_tables;
     std::shared_ptr<const ContextAccess> access;