Question

What is the easiest way in ios app to compare datetime string in sqlite3.
I store the datetime string in following way.

NSDateFormatter* df=[[NSDateFormatter alloc] init];
    [df setDateFormat:@"yyyy-MM-dd HH:mm"];
    NSString* dtString=[df stringFromDate:[NSDate date]];

then I’m inserting dtString into the table. So after i want to retrieve all rows for example only for last two days.

Answer 1

sqlite3 doesn’t contain a DATETIME type so you need to think of ways of encoding it.

If you want to use the date column in a WHERE clause then you could store the time_t returned from gmtime(time(NULL)) (i.e. the time now, since UNIX epoch) and then use some simple clause to get those rows:

... WHERE date >= ?

And binding that ? to gmtime(time(NULL)) - 60**60*24*2

EDIT: If you want to stay completely in Objective-C, then the same date value can be determined from an NSDate object using:

(time_t)[date timeIntervalSince1970]