Re: [PHP-DB] MySQL Conditional Trigger

Aleksandar Vojnovic wrote:
> You could try with the <> operator.
> !=, <>    Not equal operator

Same issue as using '=':

mysql> select 2 <> null;
+-----------+
| 2 <> null |
+-----------+
|      NULL |
+-----------+
1 row in set (0.00 sec)

Comparing anything with null returns null. (I'm not asking for a 
solution, I'm stating it as fact).

> Or you could try it this way - ISNULL(col_or_data_to_check).
> Example:
> mysql> SELECT ISNULL(1+1);
> +-------------+
> | ISNULL(1+1) |
> +-------------+
> |           0 |
> +-------------+
> 1 row in set (0.02 sec)

You can also use 'coalesce' to set default value for null columns.

http://dev.mysql.com/doc/refman/5.0/en/comparison-operators.html#function_coalesce

http://dev.mysql.com/doc/refman/5.0/en/working-with-null.html

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