Re: NULL value

julie lin wrote: > > On Tue, 20 Oct 1998 18:22:23 +0100, Peter Lancashire > <Peter.Lancashire.PL1@bayer.co.uk> wrote: > > Helmut Leininger wrote: > > > > julie lin wrote: [Lots of interchange SMIPPED] > > >Also, I bet your WHERE clause looks like this: > > >WHERE mycol = ? > > >whereas what you should write is: > > >WHERE mycol IS NULL > > I know " WHERE mycol IS NULL " will work , but for some reason, > it'll be easier for me for using only dynamic SELECT statements (has > replacable parameters "?" in the where condition), I just wonder why I > can insert NULL data by using the following dynamic INSERT statement ? > [SNIP] > EXEC SQL execute ss using descriptor bind; If you are using descriptors you can set the indicator field (sqlind) to -1 and the engine will interpret your replaceable parameter as NULL. This is the correct way to insert a NULL, even into a character column, also. What actually happens when you insert the explicit NULL string is that the engine thinks it is inserting a valid string, it does not parse the string at all to see if it is valid at insert time, but at fetch time the NULL first byte causes the engine to interpret the column as NULL and to set the indicator in the descriptor/sqlda. Art S. Kagel