Re: BUG #2003: Bug with SQL UPDATE on a NUMERIC

On Thu, 27 Oct 2005, David Pujol wrote:

> Hello, I've noticed a bug when I modify a quantity with an INSERT and a
> minus operator.
> My request is:
> UPDATE products SET pr_stock=pr_stock--1 WHERE pr_code=600;
>
> I haven't SQL error but 'pr_stock' value (numeric(5,1)) is unchanged : no
> increment or decrement.
>
> I've made tests:
> - 'pr_stock=pr_stock +- 1' is OK (substraction -1)
> - 'pr_stock=pr_stock ++ 1' is OK ( +1)
> - 'pr_stock=pr_stock -+ 1' is OK ( -1)
> - 'pr_stock=pr_stock -- 1' is not OK (no change, no error)
>
> Same things with brackets :
> - 'pr_stock=pr_stock +(- 1)' is OK (substraction -1)
> - 'pr_stock=pr_stock +(+ 1)' is OK ( +1)
> - 'pr_stock=pr_stock -(+ 1)' is OK ( -1)
> - 'pr_stock=pr_stock -(- 1)' is not OK (no change, no error)

I cannot reproduce the second case here on 8.0.x + Linux.  I get an
addition of 1.  The first case is user error I think because I believe --
is the comment beginning marker.