Mike Machado wrote:
>
> I did an alter table to add a column called billgroup as an int(10)
>
> This worked ok and it set all the existing rows to have "NULL" in the
> new column. So I figured I would do a mass update to switch it then to
> "1". These are the statements I executed but did not seem to change
> anything:
>
> select billgroup from account limit 10;
>
> +-----------+
> | billgroup |
> +-----------+
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> +-----------+
> 10 rows in set (0.01 sec)
>
> update account set billgroup = "1" where billgroup = "NULL";
> update account set billgroup = "1" where billgroup = NULL;
> update account set billgroup = "1" where billgroup = "";
> update account set billgroup = "1" where billgroup = '';
> update account set billgroup = "1" where billgroup = "0";
>
> select billgroup from account limit 10;
> +-----------+
> | billgroup |
> +-----------+
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> | NULL |
> +-----------+
> 10 rows in set (0.01 sec)
>
> ?
>
> What is the where clause I have to use to match the data in the columns
> after an alter table?
>
> MySQL 3.22.13 - Linux 2.0.36 libc5
>
> --
> Mike Machado
Hi Mike
Please do never ever compare NULL with = or <> or !=.
Always use xxxx IS NULL or xxxx IS NOT NULL!
So you should use:
UPDATE account SET billgroup = 1 WHERE billgroup IS NULL
Tschau
Christian
