diff --git a/ch/chschema/column.go b/ch/chschema/column.go
index 735540d..fb68d67 100644
--- a/ch/chschema/column.go
+++ b/ch/chschema/column.go
@@ -2,6 +2,7 @@ package chschema
 
 import (
 	"bytes"
+	"database/sql"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -111,17 +112,77 @@ func (c ColumnOf[T]) Slice(s, e int) any {
 	return c.Column[s:e]
 }
 
+func (c *ColumnOf[T]) appendSliceColumn(v reflect.Value) {
+	colElemType := reflect.TypeOf(c.Column).Elem().Elem()
+	col := reflect.MakeSlice(reflect.SliceOf(colElemType), 0, v.Len())
+	for i := 0; i < v.Len(); i++ {
+		col = reflect.Append(col, v.Index(i).Convert(colElemType))
+	}
+	c.Column = append(c.Column, col.Interface().(T))
+}
+
 func (c *ColumnOf[T]) AppendValue(v reflect.Value) {
+	if reflect.TypeOf(c.Column).Elem().Kind() == reflect.Slice && v.Kind() == reflect.Slice {
+		c.appendSliceColumn(v)
+		return
+	}
 	c.Column = append(c.Column, v.Interface().(T))
 }
 
+func (c *ColumnOf[T]) convertSliceColumn(slice T, destSlice reflect.Value) {
+	sliceValue := reflect.ValueOf(slice)
+	elemType := destSlice.Type().Elem()
+
+	ret := reflect.MakeSlice(reflect.SliceOf(elemType), 0, sliceValue.Len())
+	for i := 0; i < sliceValue.Len(); i++ {
+		ret = reflect.Append(ret, sliceValue.Index(i).Convert(elemType))
+	}
+
+	destSlice.Set(ret)
+}
+
 func (c *ColumnOf[T]) ConvertAssign(idx int, dest reflect.Value) error {
+	if reflect.TypeOf(c.Column).Elem().Kind() == reflect.Slice && dest.Kind() == reflect.Slice {
+		c.convertSliceColumn(c.Column[idx], dest)
+		return nil
+	}
 	dest.Set(reflect.ValueOf(c.Column[idx]))
 	return nil
 }
 
 //------------------------------------------------------------------------------
 
+func convertAssignDriverValue(col any, v reflect.Value) bool {
+	var ret reflect.Value
+
+	if _, ok := v.Interface().(sql.Scanner); !ok {
+		if !v.CanAddr() {
+			return false
+		}
+		if _, ok := v.Addr().Interface().(sql.Scanner); !ok {
+			return false
+		}
+
+		ret = reflect.New(v.Type())
+		if err := ret.Interface().(sql.Scanner).Scan(col); err != nil {
+			return false
+		}
+
+		v.Set(ret.Elem())
+		return true
+	}
+
+	ret = reflect.New(v.Type().Elem())
+	if err := ret.Interface().(sql.Scanner).Scan(col); err != nil {
+		return false
+	}
+
+	v.Set(ret)
+	return true
+}
+
+//------------------------------------------------------------------------------
+
 type NumericColumnOf[T constraints.Integer | constraints.Float] struct {
 	ColumnOf[T]
 }
@@ -135,7 +196,11 @@ func (c NumericColumnOf[T]) ConvertAssign(idx int, v reflect.Value) error {
 	case reflect.Float32, reflect.Float64:
 		v.SetFloat(float64(c.Column[idx]))
 	default:
-		v.Set(reflect.ValueOf(c.Column[idx]))
+		if !convertAssignDriverValue(c.Column[idx], v) {
+			v.Set(reflect.ValueOf(c.Column[idx]))
+			return nil
+		}
+		return nil
 	}
 	return nil
 }
@@ -156,7 +221,7 @@ func (c StringColumn) ConvertAssign(idx int, v reflect.Value) error {
 		v.SetString(c.Column[idx])
 		return nil
 	case reflect.Slice:
-		if v.Type() == bytesType {
+		if v.Type() == bytesType || v.Type() == reflect.TypeOf((*json.RawMessage)(nil)).Elem() {
 			v.SetBytes(internal.Bytes(c.Column[idx]))
 			return nil
 		}
@@ -165,7 +230,31 @@ func (c StringColumn) ConvertAssign(idx int, v reflect.Value) error {
 		dec.UseNumber()
 		return dec.Decode(v.Addr().Interface())
 	default:
-		v.Set(reflect.ValueOf(c.Column[idx]))
+		if !convertAssignDriverValue(c.Column[idx], v) {
+			// v.Set(reflect.ValueOf(c.Column[idx]))
+			return nil
+		}
+		return nil
+	}
+	return fmt.Errorf("ch: can't scan %s into %s", "string", v.Type())
+}
+
+//------------------------------------------------------------------------------
+
+func (c *UInt256Column) ConvertAssign(idx int, v reflect.Value) error {
+	switch v.Kind() {
+	case reflect.String:
+		v.SetString(c.Column[idx].String())
+		return nil
+	case reflect.Slice:
+		if v.Type() == bytesType {
+			v.SetBytes(internal.Bytes(string(c.Column[idx].Bytes())))
+			return nil
+		}
+	default:
+		if !convertAssignDriverValue(c.Column[idx].String(), v) {
+			return fmt.Errorf("ch: convertAssign UInt256 %x", c.Column[idx])
+		}
 		return nil
 	}
 	return fmt.Errorf("ch: can't scan %s into %s", "string", v.Type())
diff --git a/ch/chschema/column_gen.go b/ch/chschema/column_gen.go
index 5180b68..c1c7249 100644
--- a/ch/chschema/column_gen.go
+++ b/ch/chschema/column_gen.go
@@ -1,12 +1,42 @@
 package chschema
 
 import (
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+	"math/big"
 	"reflect"
+	"strconv"
 	"time"
 
 	"github.com/uptrace/go-clickhouse/ch/chproto"
 )
 
+func getDriverValue(v reflect.Value) driver.Value {
+	if v.Kind() == reflect.Pointer && v.IsNil() {
+		return nil
+	}
+
+	dv, ok := v.Interface().(driver.Valuer)
+	if !ok {
+		if !v.CanAddr() {
+			return nil
+		}
+		if dv, ok = v.Addr().Interface().(driver.Valuer); !ok {
+			return nil
+		}
+	}
+
+	value, err := dv.Value()
+	if err != nil {
+		return nil
+	}
+
+	return value
+}
+
+//------------------------------------------------------------------------------
+
 type Int8Column struct {
 	NumericColumnOf[int8]
 }
@@ -1396,7 +1426,116 @@ func (c *UInt64Column) Type() reflect.Type {
 }
 
 func (c *UInt64Column) AppendValue(v reflect.Value) {
-	c.Column = append(c.Column, uint64(v.Uint()))
+	switch v.Kind() {
+	case reflect.Uint, reflect.Uintptr, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		c.Column = append(c.Column, v.Uint())
+	case reflect.String:
+		i, err := strconv.ParseInt(v.String(), 10, 64)
+		if err != nil {
+			return
+		}
+		c.Column = append(c.Column, uint64(i))
+	case reflect.Pointer:
+		if v.IsNil() {
+			c.Column = append(c.Column, 0)
+			return
+		}
+		c.AppendValue(v.Elem())
+	default:
+		value := getDriverValue(v)
+		if value != nil {
+			c.AppendValue(reflect.ValueOf(value))
+			return
+		}
+		c.Column = append(c.Column, v.Uint())
+	}
+}
+
+//------------------------------------------------------------------------------
+
+type UInt256Column struct {
+	ColumnOf[*big.Int]
+}
+
+var _ Columnar = (*UInt256Column)(nil)
+
+func NewUInt256Column() Columnar {
+	return new(UInt256Column)
+}
+
+var _UInt256Type = reflect.TypeOf((*big.Int)(nil)).Elem()
+
+const u256sz = 256 / 8
+
+func (c *UInt256Column) Type() reflect.Type {
+	return _UInt256Type
+}
+
+func (c *UInt256Column) AppendValue(v reflect.Value) {
+	switch v.Kind() {
+	case reflect.Uint, reflect.Uintptr, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		c.Column = append(c.Column, new(big.Int).SetUint64(v.Uint()))
+	case reflect.String:
+		i, ok := new(big.Int).SetString(v.String(), 10)
+		if !ok {
+			return
+		}
+		c.Column = append(c.Column, i)
+	case reflect.Slice:
+		ba, ok := v.Interface().([]byte)
+		if !ok {
+			return
+		}
+		c.Column = append(c.Column, new(big.Int).SetBytes(ba))
+	case reflect.Pointer:
+		if v.IsNil() {
+			c.Column = append(c.Column, new(big.Int))
+			return
+		}
+		c.AppendValue(v.Elem())
+	default:
+		value := getDriverValue(v)
+		if value != nil {
+			c.AppendValue(reflect.ValueOf(value))
+			return
+		}
+	}
+}
+
+func (c *UInt256Column) ReadFrom(rd *chproto.Reader, numRow int) error {
+	c.AllocForReading(numRow)
+
+	for it := range c.Column {
+		b := make([]byte, u256sz, u256sz)
+		n, err := rd.Read(b)
+		if err != nil {
+			return err
+		}
+		if n != u256sz {
+			return fmt.Errorf("expected read bytes %d, got %d", u256sz, n)
+		}
+		for i := 0; i < len(b)/2; i++ {
+			b[i], b[len(b)-i-1] = b[len(b)-i-1], b[i]
+		}
+		c.Column[it] = new(big.Int).SetBytes(b)
+	}
+
+	return nil
+}
+
+func (c *UInt256Column) WriteTo(wr *chproto.Writer) error {
+	for _, n := range c.Column {
+		if n.BitLen() > 256 {
+			return fmt.Errorf("%s has bigger len %d than 256", n, n.BitLen())
+		}
+		b := make([]byte, u256sz, u256sz)
+		b = n.FillBytes(b)
+		for i := 0; i < len(b)/2; i++ {
+			b[i], b[len(b)-i-1] = b[len(b)-i-1], b[i]
+		}
+		wr.Write(b)
+	}
+	return nil
 }
 
 //------------------------------------------------------------------------------
@@ -2201,7 +2340,37 @@ func (c *StringColumn) Type() reflect.Type {
 }
 
 func (c *StringColumn) AppendValue(v reflect.Value) {
-	c.Column = append(c.Column, string(v.String()))
+	if v.Kind() == reflect.Pointer && v.IsNil() {
+		c.Column = append(c.Column, "")
+		return
+	}
+
+	switch vi := v.Interface().(type) {
+	case string:
+		c.Column = append(c.Column, vi)
+	case []byte:
+		c.Column = append(c.Column, string(vi))
+	case json.RawMessage:
+		c.Column = append(c.Column, string(vi))
+	default:
+		value := getDriverValue(v)
+		if value != nil {
+			c.AppendValue(reflect.ValueOf(value))
+			return
+		}
+		if v.Kind() == reflect.String {
+			c.Column = append(c.Column, v.String())
+			return
+		}
+		j, err := json.Marshal(vi)
+		if err != nil {
+			panic(err)
+		}
+		if string(j) == "null" {
+			j = nil
+		}
+		c.Column = append(c.Column, string(j))
+	}
 }
 
 func (c *StringColumn) ReadFrom(rd *chproto.Reader, numRow int) error {
diff --git a/ch/chschema/types.go b/ch/chschema/types.go
index f0e737b..970ea03 100644
--- a/ch/chschema/types.go
+++ b/ch/chschema/types.go
@@ -93,6 +93,8 @@ func ColumnFactory(chType string, typ reflect.Type) NewColumnFunc {
 		return NewUInt32Column
 	case chtype.UInt64:
 		return NewUInt64Column
+	case chtype.UInt256:
+		return NewUInt256Column
 	case chtype.Float32:
 		return NewFloat32Column
 	case chtype.Float64:
diff --git a/ch/chtype/chtype.go b/ch/chtype/chtype.go
index 8d60ca5..24079e8 100644
--- a/ch/chtype/chtype.go
+++ b/ch/chtype/chtype.go
@@ -13,6 +13,7 @@ const (
 	UInt16     = "UInt16"
 	UInt32     = "UInt32"
 	UInt64     = "UInt64"
+	UInt256    = "UInt256"
 	Float32    = "Float32"
 	Float64    = "Float64"
 	DateTime   = "DateTime"