MySql and NULL


OSNN Newbie
13 Jan 2004
When checking the database to see if a value has been inserted into a field marked NULL do you actually check it as NULL or do you check it as an empty string ( "" ) ?
an empty string is not a NULL. if its NULL then it needs to be checked as NULL. If you've inserted it as a blank string the it is not null
NULL and a blank string are basically the same thing in MySQL Khayman, they both mean the field is empty, and both will suffice.

So this:

SELECT * FROM table WHERE string = '';

is the same as

SELECT * FROM table WHERE string = 'NULL';
Does it? thats pretty stupid, that was the whole point of NULL.
Doesn't in any other SQL DBMS.
Khayman said:
Does it? thats pretty stupid, that was the whole point of NULL.
Doesn't in any other SQL DBMS.

I have always used it interchangeably with MySQL, like you said, no other ones do it.
as no others do it, then probably better to use the version with NULL in it as it will make your code more portable should you want to change your RDBMS to something else, also makes learning the syntax or getting used to the syntax of other RDBMS's a slight bit easier

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