if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(column)
		}
	} else {
		builder.WriteByte('*')
	}
}

// MergeClause merge order by clauses
func (returning Returning) MergeClause(clause *Clause) {
	if v, ok := clause.Expression.(Returning); ok && len(returning.Columns) > 0 {
		if v.Columns != nil {
			returning.Columns = append(v.Columns, returning.Columns...)
		} else {

		}
	} else {
		builder.WriteQuoted(Column{Name: PrimaryKey})
		builder.WriteByte('=')
		builder.WriteQuoted(Column{Name: PrimaryKey})
	}
}

// MergeClause merge assignments clauses
func (set Set) MergeClause(clause *Clause) {
	copiedAssignments := make([]Assignment, len(set))
	copy(copiedAssignments, set)
	clause.Expression = Set(copiedAssignments)
}

// Assignments implements Assigner for Set.

// Package clause provides the clause interface and common clause implementations for GORM.
package clause

// Interface clause interface
type Interface interface {
	Name() string
	Build(Builder)
	MergeClause(*Clause)
}

// 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)
}

}

func (sd emptyQueryClause) Name() string {
	return "empty"
}

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

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

func (sd emptyQueryClause) ModifyStatement(stmt *gorm.Statement) {
	// do nothing
}

func TestAssociationEmptyQueryClause(t *testing.T) {
	type Organization struct {

				stmt.AddVar(writer, nil)
			} else {
				stmt.AddVar(writer, v.GormValue(stmt.Context, stmt.DB))
			}
		case clause.Interface:
			c := clause.Clause{Name: v.Name()}
			v.MergeClause(&c)
			c.Build(stmt)
		case clause.Expression:
			v.Build(stmt)
		case driver.Valuer:
			stmt.Vars = append(stmt.Vars, v)
			stmt.DB.Dialector.BindVarTo(writer, stmt, v)
		case []byte: