[Kotlin][Exposed] How to use asterisk in Exposed-Query

KotlinExposedUsingAsteriskInQuery.kt

fun queryUsingAsterisk(clientId: Long): Query {

    val tableAlias = InvoiceTable.alias("i")

    val asterisk = object : Expression<String>() {
        override fun toQueryBuilder(queryBuilder: QueryBuilder) {
            queryBuilder { +"*" }
        }
    }

    return InvoiceTable.alias("i")
        .slice(asterisk)
        .select { tableAlias[InvoiceTable.client].eq(clientId) }
        .andWhere { tableAlias[InvoiceTable.id] eq InvoiceTable.id }
        .andWhere { tableAlias[InvoiceTable.origin].eqSubQuery(subQuery(clientId)) }
        .andWhere { tableAlias[InvoiceTable.invoiceType] eq InvoiceTypeEnum.TR.value }
}