writer.WriteByte('(')
		for idx, d := range v {
			if idx > 0 {
				writer.WriteByte(',')
			}
			stmt.QuoteTo(writer, d)
		}
		writer.WriteByte(')')
	case clause.Expr:
		v.Build(stmt)
	case string:
		stmt.DB.Dialector.QuoteTo(writer, v)
	case []string:
		writer.WriteByte('(')
		for idx, d := range v {
			if idx > 0 {
				writer.WriteByte(',')
			}
			stmt.DB.Dialector.QuoteTo(writer, d)

	return clause.Expr{SQL: "DEFAULT"}
}

func (DummyDialector) Migrator(*gorm.DB) gorm.Migrator {
	return nil
}

func (DummyDialector) BindVarTo(writer clause.Writer, stmt *gorm.Statement, v interface{}) {
	writer.WriteByte('?')
}

func (DummyDialector) QuoteTo(writer clause.Writer, str string) {
	var (
		underQuoted, selfQuoted bool
		continuousBacktick      int8
		shiftDelimiter          int8
	)

type Dialector interface {
	Name() string
	Initialize(*DB) error
	Migrator(db *DB) Migrator
	DataTypeOf(*schema.Field) string
	DefaultValueOf(*schema.Field) clause.Expression
	BindVarTo(writer clause.Writer, stmt *Statement, v interface{})
	QuoteTo(clause.Writer, string)
	Explain(sql string, vars ...interface{}) string
}

// Plugin GORM plugin interface
type Plugin interface {
	Name() string
	Initialize(*DB) error
}

const (
	// Silent silent log level
	Silent LogLevel = iota + 1
	// Error error log level
	Error
	// Warn warn log level
	Warn
	// Info info log level
	Info
)

// Writer log writer interface
type Writer interface {
	Printf(string, ...interface{})
}

// Config logger config
type Config struct {
	SlowThreshold             time.Duration
	Colorful                  bool

// ClauseBuilder clause builder, allows to customize how to build clause
type ClauseBuilder func(Clause, Builder)

type Writer interface {
	WriteByte(byte) error
	WriteString(string) (int, error)
}

// Builder builder interface
type Builder interface {
	Writer
	WriteQuoted(field interface{})
	AddVar(Writer, ...interface{})
	AddError(error) error
}

// Clause
type Clause struct {
	Name                string // WHERE

package gorm

import (
	"context"
	"database/sql"
	"database/sql/driver"
	"errors"
	"reflect"
	"sync"
)

type Stmt struct {
	*sql.Stmt
	Transaction bool
	prepared    chan struct{}
	prepareErr  error
}

type PreparedStmtDB struct {
	Stmts       map[string]*Stmt
	PreparedSQL []string
	Mux         *sync.RWMutex
	ConnPool
}

func NewPreparedStmtDB(connPool ConnPool) *PreparedStmtDB {

package tests_test

import (
	"context"
	"database/sql"
	"database/sql/driver"
	"encoding/json"
	"errors"
	"fmt"
	"reflect"
	"regexp"
	"strconv"
	"testing"
	"time"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"
	. "gorm.io/gorm/utils/tests"
)

func TestScannerValuer(t *testing.T) {
	DB.Migrator().DropTable(&ScannerValuerStruct{})
	if err := DB.Migrator().AutoMigrate(&ScannerValuerStruct{}); err != nil {

	yval := reflect.ValueOf(y)
	if xval.Kind() == reflect.Ptr && xval.IsNil() ||
		yval.Kind() == reflect.Ptr && yval.IsNil() {
		return false
	}

	if valuer, ok := x.(driver.Valuer); ok {
		x, _ = valuer.Value()
	}
	if valuer, ok := y.(driver.Valuer); ok {
		y, _ = valuer.Value()
	}
	return reflect.DeepEqual(x, y)
}

func ToString(value interface{}) string {
	switch v := value.(type) {
	case string:

	"database/sql"
	"database/sql/driver"
	"encoding/json"
	"reflect"

	"github.com/jinzhu/now"
	"gorm.io/gorm/clause"
	"gorm.io/gorm/schema"
)

type DeletedAt sql.NullTime

// Scan implements the Scanner interface.
func (n *DeletedAt) Scan(value interface{}) error {
	return (*sql.NullTime)(n).Scan(value)
}

// Value implements the driver Valuer interface.
func (n DeletedAt) Value() (driver.Value, error) {
	if !n.Valid {

package clause

import (
	"database/sql"
	"database/sql/driver"
	"go/ast"
	"reflect"
)

// Expression expression interface
type Expression interface {
	Build(builder Builder)
}

// NegationExpressionBuilder negation expression builder
type NegationExpressionBuilder interface {
	NegationBuild(builder Builder)
}

// Expr raw expression
type Expr struct {
	SQL                string
	Vars               []interface{}