If json is Unmarshaled using json.Number format like:

my_map := make(map[string]interface{})
d := json.NewDecoder(strings.NewReader(json_raw))
d.UseNumber()
d.Decode(&my_map)

And then used to search:

var expr1 = jmespath.MustCompile("people[?age > `20`].[name, age]")
result, err := expr1.Search(my_map)

err is nil but the result is [] even though some objects must be returned. Removing the d.UseNumber() makes the Search work properly.

This is probably because this type assertion fails to recognize the value in the map as a Number (float): https://github.com/jmespath/go-jmespath/blob/master/interpreter.go#L48

json.Number is essentially a string. So either reflect/conversion library can be used here or type assertion should handle json.Number.