I am trying to make a request to my database using Exposed, everywhere I'am looking it says that i need to put the condition in the function body like so:

    override suspend fun getCarModel(carModelId: Int): CarModel? {
        return transaction {
            addLogger(StdOutSqlLogger)
            CarModels
                .select {CarModels.id eq carModelId}
                .mapNotNull { row ->
                    CarModel(
                        id = row[CarModels.id],
                        brand = row[CarModels.brand],
                        model = row[CarModels.model],
                        year = row[CarModels.year]
                    )
                }.singleOrNull()
        }
    }

Doing this way I get an error of:

Type mismatch.
Required: List<Expression<*>> Found: () → Op

I've also tried putting the condition in the function arguments

.select(CarModels.id eq carModelId)

or .select{(CarModels.id eq carModelId)} but this way I get:

com.carspotter.data.table.CarModels.id is not in record set java.lang.IllegalStateException: com.carspotter.data.table.CarModels.id is not in record set.

This is my table declaration:

object CarModels : Table("car_models") {
    val id = integer("id").autoIncrement()
    val brand = varchar("brand", 50)
    val model = varchar("model", 50)
    val year = integer("year").nullable()

    override val primaryKey = PrimaryKey(id)

    init {
        uniqueIndex(brand, model, year)
    }

}

My question is what am I doing wrong that the first approach doesn't work? Also, I am using Exposed version 0.60.0 for core, jdbc and dao.

I am trying to make a request to my database using Exposed, everywhere I'am looking it says that i need to put the condition in the function body like so:

    override suspend fun getCarModel(carModelId: Int): CarModel? {
        return transaction {
            addLogger(StdOutSqlLogger)
            CarModels
                .select {CarModels.id eq carModelId}
                .mapNotNull { row ->
                    CarModel(
                        id = row[CarModels.id],
                        brand = row[CarModels.brand],
                        model = row[CarModels.model],
                        year = row[CarModels.year]
                    )
                }.singleOrNull()
        }
    }

Doing this way I get an error of:

Type mismatch.
Required: List<Expression<*>> Found: () → Op

I've also tried putting the condition in the function arguments

.select(CarModels.id eq carModelId)

or .select{(CarModels.id eq carModelId)} but this way I get:

com.carspotter.data.table.CarModels.id is not in record set java.lang.IllegalStateException: com.carspotter.data.table.CarModels.id is not in record set.

This is my table declaration:

object CarModels : Table("car_models") {
    val id = integer("id").autoIncrement()
    val brand = varchar("brand", 50)
    val model = varchar("model", 50)
    val year = integer("year").nullable()

    override val primaryKey = PrimaryKey(id)

    init {
        uniqueIndex(brand, model, year)
    }

}

My question is what am I doing wrong that the first approach doesn't work? Also, I am using Exposed version 0.60.0 for core, jdbc and dao.

• postgresql
• kotlin
• kotlin-exposed

• Can you show the SQL equivalent SELECT query you are trying to code in Exposed? – k314159 Commented Mar 31 at 12:19
• This the query I am trying to execute: SELECT car_models.id, car_models.brand, car_models.model, car_models.year FROM car_models WHERE car_models.id = 1 – Andrei Rusu Commented Apr 1 at 11:13

1 Answer 1

The message explains what is causing the error:

Type mismatch.
Required: List<Expression<*>>
Found: () -> Op

The select function, just like the SQL SELECT statement, takes a list of columns, but you are passing a lambda to the select function (hence Found: () -> Op). You need to pass the condition to the where function instead:

CarModels
    .select(listOf(CarModels.id, CarModels.brand, CarModels.model, CarModels.year))
    .where { CarModels.id eq carModelId }