Add exists() method on Query to check assert the existence of a query

Suggested Enhancement: Adding an exists() method on Query would allow to efficiently check the existence of a row or group of rows. Would be the SQL equivalent of SELECT EXISTS(SELECT 1 FROM table WHERE ...)

Exemple: FooTable.select { FooTable.id eq 5 }.exists() would be converted to: SELECT EXISTS(SELECT 1 FROM FooTable WHERE id = 5)

[damienmiheev]

It looks quite complex to use. Why don’t to add something like: val result: Boolean = FooTable.exists { FooTable.id eq 5 }

For example

fun <T: FieldSet> T.exists(where: SqlExpressionBuilder.() -> Op<Boolean>): Boolean {
    val existsOp = exists(this.select(where))
    val result = Table.Dual.slice(existsOp).selectAll().first()
    return result[existsOp]
}

[Tapac]

Yes, the “FROM” part will be skiped for PSQL for Table.Dual.