Question

Why is this

SELECT strftime('%s', timestamp,'localtime') from locationLog WHERE strftime('%s', timestamp,'localtime') > 999999999999999999 ORDER BY _id DESC

return any outputs when all of my rows have a lower value in “timestamp”

in my case the query above returns

1334735588
1334735349
1334734317
1334734178
1334734172
and so on...

it returns my whole table.

if I switch > to < it returns nothing.

I guess I’m trying to compare different type of variables or something like that.

Answer 1

You are comparing a text value with a integer value, so sqlite casts the integer value to text, and does a string comparison:

sqlite> select strftime('%s', '2002-02-02', 'localtime');
1012611600
sqlite> select typeof(strftime('%s', '2002-02-02', 'localtime'));
text
sqlite> select typeof(999999999999999999);
integer
sqlite> select strftime('%s', '2002-02-02', 'localtime') > 999999999999999999;
1
sqlite> select cast(strftime('%s', '2002-02-02', 'localtime') as integer) > 999999999999999999;
0

As shown above, the solution is to cast the returned value of strftime to some numeric type.