As I said several times:
Provide a test aia.
(Otherwise we'll keep going in circles.)
Thanks to the responses here, It's clear to me now that this is not about the code issue, its about how mysql handles the empty string input. it looks like it considers an empty string a completely nothing, it won't output an empty string or Null value (no value at all).
by AI2, PHP, mysql or csv? I know that an empty string is saved to mysql because I set the column as NULL (i.e. if nothing is saved there, the value is NULL). After GET, CSV to List. When i tried to access the element in the list, no empty string is there and the list is shorter than i expected.
MYSQL has a facility to export the SQL Table creation command for your table, right?
Export it and post it here, so we can take stabs at changing that behavior.
im using online mysql db, cannot export the history of command
You should be very careful if you're planning to take the user input and send it to your database (relevant XKCD). Since it sounds like you are looking to insert/update three columns, you may want to try something like this:
In this case, if the textbox is empty you'll get the value list (as a string):
'a','','c'
which could be used in an UPDATE clause, for example.
Thanks for the suggestion. I tested this with both " (double quotation mark) and ''(two single quotation marks) at "replacement", it returns the same number of elements like before, the empty string is just ignored. Unless there is an ideal solution, I will be using a blank space preset at the box. It looks like the empty string was sent to the database (otherwise the value there shold be Null, but when I looked at the db, the data there was not Null, it's empty). I read somewhere that mysql considers blank string the same as blank, so when retrieving data from there, it's just nothing. or it's also possible that it's lost when converted to csv or when csv is converted to list.