It's not possible for a column value to be equal to NULL; hence the SQL
syntax is 'IS NULL'. However, in an UPDATE statement, writing
'columnA=NULL' is valid, as in this context '=' is an assignment, not a
relationship operator.
Regards.
rayB
|---------+---------------------------->
| | Tito Ciuro |
| | <[EMAIL PROTECTED]> |
| | |
| | 28/10/2004 08:55 |
| | AM |
| | Please respond to|
| | sqlite-users |
| | |
|---------+---------------------------->
>------------------------------------------------------------------------------------------------------------------------------|
|
|
| To: Forum SQLite <[EMAIL PROTECTED]>
|
| cc:
|
| Subject: [sqlite] How are NULL values deleted?
|
>------------------------------------------------------------------------------------------------------------------------------|
Hello,
I'd like to remove all rows with a specific column equaling NULL. I've
tried this:
SQLite version 3.0.8
Enter ".help" for instructions
sqlite> select * from address;
Ciurķ|1|Javi||Espaņa
Garaicoechevarria|2|Ana||Espaņa
Ciurķ|3|Tito||Espaņa
Miti|4|Sam||Italy
Schmuck|5|Joe||Germany
sqlite> delete from address where ZIP = NULL;
sqlite> select * from address;
Ciurķ|1|Javi||Espaņa
Garaicoechevarria|2|Ana||Espaņa
Ciurķ|3|Tito||Espaņa
Miti|4|Sam||Italy
Schmuck|5|Joe||Germany
sqlite> delete from address where ZIP = 'NULL';
sqlite> select * from address;
Ciurķ|1|Javi||Espaņa
Garaicoechevarria|2|Ana||Espaņa
Ciurķ|3|Tito||Espaņa
Miti|4|Sam||Italy
Schmuck|5|Joe||Germany
Since all rows have NULL for ZIP, I would expect to remove all rows,
but I cannot figure it out...
Any ideas?
Thanks,
-- Tito
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