Re: informix alter table with syntax error in unix

> > If you add the NULL yourself your problem will be solved: > check ((field_a IS NULL ) OR (field_a IN ('A' ,'B' ,'C' ))) > But remember that using an OR operator may significantly decrease query performance!

Iztok Bofulin wrote: >> If you add the NULL yourself your problem will be solved: >> check ((field_a IS NULL ) OR (field_a IN ('A' ,'B' ,'C' ))) >> > > But remember that using an OR operator may significantly decrease > query performance! Not on a constraint especially in this circumstance. It's just an inline expression that is applied to test the value of a field. There is no touching the tables or performing queries when this expression is executed, so it will run at full CPU speed in a few dozen clock cycles as expected.