When doing an insert, an empty string is converted to null: insert into test (f) values (''); Now, there is a row with f containing a null. But, when I query the table, I cannot use '': select * ...
In my MySQL DB I have one field called html_contents that contains all the html to be shown in a webpage. Obviously the html could be huge, and certaintly bigger than 64KB, therefore I decided to use ...
I have 3 indexed fields in a query: int, int, and varchar(250). The query performs well when all 3 conditions are specified with real values. The int columns always have values, but there are plenty ...
I understand that questions similar to these pop up often around here. I have searched before posting these but I didn't find any QA threads that completely answer my questions. In a table, I ...
I have a bunch of queries, against a couple different databases, that I use to generate delimited reports. I'm trying to create some new reports against a MSSQL database and I'm having trouble ...
I'm interested mainly in MySQL and PostgreSQL, but you could answer the following in general: Is there a logical scenario in which it would be useful to distinguish an empty string from NULL? What ...