I am using sequelize 5.21.8 and I have to calculate the min and max of a column, so I use `fn.min` and `fn.max` . 

My mapping is like so

```
startTime: {
  field:'signaldate',
  type: Sequelize.DATE
} ,

```

and for that column my query is 

```
    return Signals.findAll({
      attributes:[
        [Sequelize.fn('max', Sequelize.col('signaldate')), 'maxdateallowed'],
        [Sequelize.fn('min', Sequelize.col('signaldate')), 'maxdateallowed']
      ]   
    })

```

The problem is that I have to use the original column name inside the `Sequelize.fn('max'`, in the `Sequelize.col` part. The query works, but the mapping does snot.

If I use the `startTime` as I set in the mapping, like so

```
    [Sequelize.fn('max', Sequelize.col('startTime')), 'maxdateallowed'],

```

then I get an error

> 
> SequelizeDatabaseError: Unknown column 'startTime' in 'field list'
> 
> 
> 

How can I use mapping in that case and not have an error? 

Thanks