}

		builder.WriteString("JOIN ")
		builder.WriteQuoted(join.Table)

		if len(join.ON.Exprs) > 0 {
			builder.WriteString(" ON ")
			join.ON.Build(builder)
		} else if len(join.Using) > 0 {
			builder.WriteString(" USING (")
			for idx, c := range join.Using {
				if idx > 0 {
					builder.WriteByte(',')
				}
				builder.WriteQuoted(c)
			}
			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

func (returning Returning) Build(builder Builder) {
	if len(returning.Columns) > 0 {
		for idx, column := range returning.Columns {
			if idx > 0 {
				builder.WriteByte(',')
			}

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

// MergeClause merge order by clauses
func (returning Returning) MergeClause(clause *Clause) {

	return stmt.SQL.WriteString(str)
}

// WriteByte write byte
func (stmt *Statement) WriteByte(c byte) error {
	return stmt.SQL.WriteByte(c)
}

// WriteQuoted write quoted value
func (stmt *Statement) WriteQuoted(value interface{}) {
	stmt.QuoteTo(&stmt.SQL, value)
}

// QuoteTo write quoted value to writer
func (stmt *Statement) QuoteTo(writer clause.Writer, field interface{}) {