return "GROUP BY"
}

// Build build group by clause
func (groupBy GroupBy) Build(builder Builder) {
	for idx, column := range groupBy.Columns {
		if idx > 0 {
			builder.WriteByte(',')
		}

		builder.WriteQuoted(column)
	}

	if len(groupBy.Having) > 0 {
		builder.WriteString(" HAVING ")
		Where{Exprs: groupBy.Having}.Build(builder)
	}
}

// MergeClause merge group by clause

}

// Build build from clause
func (from From) Build(builder Builder) {
	if len(from.Tables) > 0 {
		for idx, table := range from.Tables {
			if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(table)
		}
	} else {
		builder.WriteQuoted(currentTable)
	}

	for _, join := range from.Joins {
		builder.WriteByte(' ')
		join.Build(builder)
	}
}

// MergeClause merge from clause

package clause

type Delete struct {
	Modifier string
}

func (d Delete) Name() string {
	return "DELETE"
}

func (d Delete) Build(builder Builder) {
	builder.WriteString("DELETE")

	if d.Modifier != "" {
		builder.WriteByte(' ')
		builder.WriteString(d.Modifier)
	}
}

func (d Delete) MergeClause(clause *Clause) {
	clause.Name = ""
	clause.Expression = d

	return "ORDER BY"
}

// Build build where clause
func (orderBy OrderBy) Build(builder Builder) {
	if orderBy.Expression != nil {
		orderBy.Expression.Build(builder)
	} else {
		for idx, column := range orderBy.Columns {
			if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(column.Column)
			if column.Desc {
				builder.WriteString(" DESC")
			}
		}
	}
}

}

type SoftDeleteQueryClause struct {
	ZeroValue sql.NullString
	Field     *schema.Field
}

func (sd SoftDeleteQueryClause) Name() string {
	return ""
}

func (sd SoftDeleteQueryClause) Build(clause.Builder) {
}

func (sd SoftDeleteQueryClause) MergeClause(*clause.Clause) {
}

func (sd SoftDeleteQueryClause) ModifyStatement(stmt *Statement) {

										where.Build(&onStmt)

										if onSQL := onStmt.SQL.String(); onSQL != "" {
											vars := onStmt.Vars
											for idx, v := range vars {
												bindvar := strings.Builder{}
												onStmt.Vars = vars[0 : idx+1]
												db.Dialector.BindVarTo(&bindvar, &onStmt, v)
												onSQL = strings.Replace(onSQL, bindvar.String(), "?", 1)
											}

	QueryFields bool
	// CreateBatchSize default create batch size
	CreateBatchSize int
	// TranslateError enabling error translation
	TranslateError bool

	// ClauseBuilders clause builder
	ClauseBuilders map[string]clause.ClauseBuilder
	// ConnPool db conn pool
	ConnPool ConnPool
	// Dialector database dialector
	Dialector
	// Plugins registered plugins
	Plugins map[string]Plugin

		db.AddError(ErrUnsupportedDriver)
	}
	return db
}

// Exec executes raw sql
func (db *DB) Exec(sql string, values ...interface{}) (tx *DB) {
	tx = db.getInstance()
	tx.Statement.SQL = strings.Builder{}

	if strings.Contains(sql, "@") {
		clause.NamedExpr{SQL: sql, Vars: values}.Build(tx.Statement)
	} else {
		clause.Expr{SQL: sql, Vars: values}.Build(tx.Statement)
	}

	Expression          Expression
	Builder             ClauseBuilder
}

// Build build clause
func (c Clause) Build(builder Builder) {
	if c.Builder != nil {
		c.Builder(c, builder)
	} else if c.Expression != nil {
		if c.BeforeExpression != nil {
			c.BeforeExpression.Build(builder)
			builder.WriteByte(' ')
		}

		if c.Name != "" {
			builder.WriteString(c.Name)
			builder.WriteByte(' ')
		}

	return "FOR"
}

// Build build where clause
func (locking Locking) Build(builder Builder) {
	builder.WriteString(locking.Strength)
	if locking.Table.Name != "" {
		builder.WriteString(" OF ")
		builder.WriteQuoted(locking.Table)
	}

	if locking.Options != "" {
		builder.WriteByte(' ')
		builder.WriteString(locking.Options)
	}
}

// MergeClause merge order by clauses