When using rows.Values(), how can I check if one of the individual values was NULL without resorting to using .Scan()?

[ecerulm]

I've seen example of using rows.Scan(), but I already iterating over the values with rows.Values(). Is there any way to check if the value was null ?

values, err := rows.Values()
for i,v := range values {
 // how to check that v is NULL or not 
 // I can't use v == nil because it's never going to be nil 
 fmt.Println("field: ", rows.FieldDescriptions()[i], "is null?:", v == nil, "value:", v) 
 vAsPgBool, ok := v.(pgtype.Bool) 
//does not work since rows.Values() return bool, not pgtype.Bool
 if vAsPgBool, ok := v.(pgtype.Bool); ok { // does not work rows.Values() won't return a pgtype.Bool, it will return a plain regular  bool
    fmt.Println("field:", rows.FieldDescriptions()[i], "is null?:", !vAsPgBool.Valid, "value:", vAsPgBook.Bool)  
 }
}

[jackc]

In the case of a nullable boolean PostgreSQL column, I would expect you to get true, false, or nil.

If that's not the case, please provide sample code that demonstrates this behavior.

[ecerulm]

Yes, you're right. I created a table in a local postgres to test and I see different behavior there

drop table if exists table1;
create table table1 as select * from (values 
(null::bool, 'entry1'::varchar), 
(false::bool, 'entry2'::varchar),
(true::bool, 'entry3'::varchar)
)
as t (col1, col2);;
ALTER TABLE table1 OWNER TO myuser;
select * from table1;

and the following code

values, err := rows.Values()
if err != nil {
  fmt.Fprintf(os.Stderr, "Values failed: %v\n", err)
  os.Exit(1)
}
for i, v := range values {
	fmt.Println("value", i, v)
}

gives

value 0 <nil>
value 1 entry1

So the behavior I was seeing must be something else.