SQLite: Check or search for empty values

Depending on the format of your column, the value of an empty column might be NULL or an empty string.

You can filter for both using the following query ("tab" is your table, "col" the column to be searched in):

SELECT id FROM tab 
WHERE (col IS NULL) OR (col = '')

With "IS NULL" you ask whether the value of the column is NULL, with "=''" you ask whether the value is containing an empty string.

For example, if the column is containing a date, you should check for NULL, if the column is containing a text, you should check for an empty string, but of course, you can also just search for both.
Last update on 2021-07-06 | Created on 2015-04-26