Compare string (date) in sqLite DB in iOS - iphone

Question

I am storing date(in yyyy-MM-dd format) as a string in database.
And now i would like get all the records from the database wherever the date is greater than todays date.
Also i tried to do it using casting,but still didn't work out for me.
SELECT * FROM TableName WHERE CAST(valiDate AS DATETIME) >= ('2103-09-16').
Let me know in case i'm doing something wrong here.
Any solution is greatly appreciated.

Answer 1

Try this
NSDateFormatter *dateformatter = [[NSDateFormatter alloc] init];
[dateformatter setDateFormat:#"yyyy-MM-dd"];
NSString *s_tody=[dateformatter stringFromDate:[NSDate date]];
[self databaseOpen];
NSArray *temp=[[NSArray alloc]init];
NSString *s=[NSString stringWithFormat:#"select * from Task WHERE date > '%#'",s_tody];

Answer 2

If you want DB queries, you are better off using NSDate. SQLite stores the date as the number of seconds since 1/1/1970, so the comparisons are very efficient. Using strings you have string comparisons which are notoriously expensive.
You can store a date in the database like this:
float dateToStore = [theDate timeIntervalSince1970];
You can retrieve it like this:
NSDate *retrievedDate = [NSDate dateWithTimeIntervalSince1970:numberFromDB];
You can filter your query results like this:
float dateToQuery = [theDate timeIntervalSince1970];
NSString *query = [NSString stringWithFormat:
#"SELECT * FROM t1 WHERE t1.date > %#", dateToQuery];

Answer 3

First you will get the date of your system using below code.....
NSDateFormatter *dateformatter = [[NSDateFormatter alloc] init];
[dateformatter setDateFormat:#"yyyy-MM-dd"];
NSString *currentdate=[dateformatter stringFromDate:[NSDate date]];
now you can compare your current date to your database storedate using below lines.
Code for your database.
databaseName = #"youdatabase.sqlite";
documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
documentsDir = documentPaths[0];
databasePath = [documentsDir stringByAppendingPathComponent:databaseName];
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK)
{
const char *sqlStatement = [NSString stringWithFormat:#"select * from table WHERE date > '%#'",currentdate];;
}

Answer 4

convert utcStr to date
+(NSDate*) dateWithUTCStr :(NSString *)utcDateStr{
double timeInterval = [utcDateStr doubleValue];
timeInterval = timeInterval / 1000;
return [NSDate dateWithTimeIntervalSince1970:timeInterval];
}
convert date to utc
+(NSTimeInterval) UTCWithDate:(NSDate *)date{
return [date timeIntervalSince1970]*1000;
}
enjoy coding...