min / max

df.min() // min of values per every comparable column
df.min { age and weight } // min of all values in `age` and `weight`
df.minFor { age and weight } // min of values per `age` and `weight` separately
df.minOf { (weight ?: 0) / age } // min of expression evaluated for every row
df.minBy { age } // DataRow with minimal `age`

df.min()
df.age.min()
df.groupBy { city }.min()
df.pivot { city }.min()
df.pivot { city }.groupBy { name.lastName }.min()