Question

Is there a way to set a column to NULL using $wpdb->update();?

When I attempt to, WordPress attempts to typecast that column to a float, which converts NULL to 0.

I’ve checked the core code and inside of $wpdb->update(), the $format parameter is only expecting %s, %f, and %d. I went so far as to set $wpdb->field_types['myCol'] to 'NULL', but both only serve to break $wpdb->update()‘s query (interestingly enough, it shifts the values for each column over after the NULL).

There is a related question here, but that answer only deals with INSERT, not UPDATE.

From a data integrity standpoint, NULL is very important for this column, so I have to be able to set it as such when necessary.

Answer 1

As you yourself note, the $format parameter is only expecting %s, %f, and %d. The whole thing will get passed through prepare which also doesn’t take a null format specifier because it basically accepts the same format specifiers that are accepted by (v)(s)printf but without the argument swapping. You can’t pass NULL through update. You have the same choices as mentioned in the post suggested as a possible duplicate, and in essence it is.

1. Just don’t use the update function. Write your own SQL and use it with $wpdb->query. If you are dealing with your own tables that should be fine.
2. Create your own database class that will do what you want. It is a little know fact that you can replace WordPress’ $wpdb with a drop-in.