SQLite date string comparison. SAME FORMAT not working - string

Question

Please Help! This has been driving me nuts. YES I have looked at dozens of Stack Overflow answers for similar questions, and they all say "Your dates should be in a consistent accepted format".
All of my SQLite dates are stored in the following string format:
'yyyy-MM-dd HH:mm:ss'
I'm trying to do date comparison but NOTHING works. For instance:
SELECT transactiondate
FROM transactions
WHERE transactiondate >= '2010-02-19 00:00:00'
Doesn't work.. I get 0 records returned.
Even though when I run it without the WHERE clause I get returned date strings like:
'2017-02-25 00:00:00'
In fact, simply doing:
SELECT transactiondate
FROM transactions
WHERE '2017-02-25 00:00:00' >= '2010-02-19 00:00:00'
Does work, i.e. it compares the dates successfully in its raw form but not when referring to the table column value.
PLEASE.. WTF am I doing wrong?
Also, I've tried every permutation of datetime(...), date(...) in the SQL to no avail. I have also tried using ... BETWEEN ... AND ..., it doesn't help.
Thanks in advance if anyone can figure this out.

Answer 1

You got the ' in the front and end included in your data. In column transactiondate.
Then you also need to include ' chars in your WHERE filter too. Two ways to do that in SQLite:
select * from transactions where transactiondate >= "'2010-02-19 00:00:00'";
select * from transactions where transactiondate >= '''2010-02-19 00:00:00''';
However, I suggest you clean up your data instead:
update transactions
set transactiondate=substr(transactiondate,2,length(transactiondate)-2)
where transactiondate like "'%'";
Now you can use your original WHERE without the extra ' chars.

Answer 2

OK, This is not an answer. But in SO you can't do this kind of thing in a comment.
I can't replicate the condition you have. The code, in particular the SELECT, works well enough executed from Python.
>>> import sqlite3
>>> conn = sqlite3.connect(':memory:')
>>> cur = conn.cursor()
>>> cur.execute('CREATE TABLE transactions (transactionsdate string)')
<sqlite3.Cursor object at 0x000000000531CCE0>
>>> cur.execute('''INSERT INTO transactions VALUES ('2010-02-10 00:00:00')''')
<sqlite3.Cursor object at 0x000000000531CCE0>
>>> cur.execute('''INSERT INTO transactions VALUES ('2017-02-10 00:00:00')''')
<sqlite3.Cursor object at 0x000000000531CCE0>
>>> list(cur.execute("SELECT * from transactions where transactionsdate >= '2010-02-19 00:00:00'"))
[('2017-02-10 00:00:00',)]
>>> list(cur.execute("SELECT * from transactions"))
[('2010-02-10 00:00:00',), ('2017-02-10 00:00:00',)]
Stab in the dark: Can you dump the contents of the field into a text file and examine it using (say) Notepad++, which would enable to to see non-printing characters that are interfering?