Joining strings from fields with null values

[stewart palmer via AccessMonster.com]

What is wrong with the following:
UPDATE enq SET enq.DUP = Left$([enq]![n2],3)&Left$([enq]![postcode],3)&Right$([enq]![postcode],3)&Left$([enq]![a1],2)&left$([enq]![email],5);

According to ACCESS 97 Help, using & instead of + should overcome the problem of having null values in some of the fields I am using in the above query to create a unique ID.
In actual fact it behaves no differently, refusing to include the null values and consequently not updating the many records that contain the field with null value.
Stewart

*****************************************
* This message was posted via http://www.accessmonster.com
*
* Report spam or abuse by clicking the following URL:
* http://www.accessmonster.com/Uwe/Abuse.aspx?aid=cbd49c7f79b6424cb1c88a3e3232f86b
*****************************************

[Randy Harris]

You can't take a Left$ (or Right$) of a null. If [enq]![n2] is null,
Left$([enq]![n2],3) will return an error. Left$([enq]![n2] & "", 3) should
work, however, returning "" if the field value is null.
"stewart palmer via AccessMonster.com" <fo***@AccessMonster.com> wrote in
message news:cb******************************@AccessMonste r.com...

What is wrong with the following:
UPDATE enq SET enq.DUP = Left$([enq]![n2],3)&Left$([enq]![postcode],3)&Right$([enq]![postcode],3)&Lef
t$([enq]![a1],2)&left$([enq]![email],5);
According to ACCESS 97 Help, using & instead of + should overcome the problem of having null values in some of the fields I am using in the above
query to create a unique ID. In actual fact it behaves no differently, refusing to include the null values and consequently not updating the many records that contain the field
with null value. Stewart

*****************************************
* This message was posted via http://www.accessmonster.com
*
* Report spam or abuse by clicking the following URL:
* http://www.accessmonster.com/Uwe/Abuse.aspx?aid=cbd49c7f79b6424cb1c88a3e3232f86b *****************************************