<@U1DCM39JR>: not sure if this is the right way to...

# exposed

[mathiasbn]

@supaham: not sure if this is the right way to go, but then you can e.g.:```
internal fun dateFormat(dateFunc: ExpressionWithColumnType<DateTime>,format:String): Function<String> {
return BuiltInFunction<String>("DATE_FORMAT", StringColumnType(255), dateFunc, stringLiteral(format))
}
```