Looked in both PHP reference and MySQL reference, and don't see the syntax to use to set a database field to the value of NULL, using the SET field=value form of the SQL syntax.

Have:
$var = ?????;
...
INSERT INTO ... ... SET Fieldname='$var' ...

What do I set ????? to in order to make that field null?

thanks.
don

In MySQL null can have a special meaning, like triggering an auto-incremented field or resetting a timestamp. It doesn't accept a null value for a field unless you specifically tell it to.

Here is a table with the creation of a field that does accept null values:

CREATE TABLE `null_test` (
`null_field` TEXT
);

INSERT INTO `null_test` VALUES(null);

Just inserts an empty row into that table.

UPDATE `null_test` SET `null_field` = null;

Updates `null_field` in all rows in the table to null.

CREATE TABLE `null_test` (
`null_field` TEXT NOT NULL
);

Creates the same table but does not allow null values!
MySQL comes back with the error:
#1048 - Column 'null_field' cannot be null

So having said all that, in answer to your question:
its `field_name` = null

: )
Rich

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Smiling Souls
http://www.smilingsouls.net
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Thanks, Rich. I had tried setting field_name = 'null', but hadn't tried it without the quotes, which makes sense considering that null is a special value, and not just a string that says "null".
-don