The Curious Case of the Vanishing Parameter

Question

G'day
I have this <cfquery>:
<cfquery>
select col1, col2, col3, col4, col5
from myTable
where col1 in (<cfqueryparam value="#var1#"
cfsqltype="cf_sql_varchar"
list="Yes">)
and col2 = <cfqueryparam value="#var2#"
cfsqltype="cf_sql_varchar">
and col3 in (<cfqueryparam value="#var3#"
cfsqltype="cf_sql_varchar"
list="Yes">)
and col4 in (<cfqueryparam value="#var4#"
cfsqltype="cf_sql_varchar"
list="Yes">)
and col5 = <cfqueryparam value="#var5#"
cfsqltype="cf_sql_varchar">
and col6 = <cfqueryparam value="#var6#"
cfsqltype="cf_sql_numeric">
<cfquery>
On one of our servers (sadly, the production one), this is
erroring when
var1 is an empty string (which is a valid situation to
occur). Rather
curiously, the SQL being spat out by the error message is
this:
select col1, col2, col3, col4, col5
from myTable
where col1 in () <---- note this
and col2 = (param 1)
and col3 in ( (param 2) )
and col4 in ( (param 3) )
and col5 = (param 4)
and col6 = (param 5)
Note how the first param is *completely gone*. The SQL should
simply be
passing through the empty string as the parameter, but the
parameter
"anchor" should still be there. Indeed this is exactly what
happens on my
local PC, and on our shared dev environment.
Unfortunately the erroring server is not so easy for me to
access due to a
new "non-invasive" policy the client has, so it's going to be
tricky for me
to experiment by way of trying to work out "WTF?".
Has anyone encountered this sort of thing, and know what I
should be
looking to do to sort it out?
Adam

Answer 1

> happens to me from time to time and always crashes the
query (I think). I
> simply cope with by changing this:
> where col1 in (<cfqueryparam value="#var1#"
cfsqltype="cf_sql_varchar"
> list="Yes">)
> to something like this:
> where col1 in (<cfqueryparam
value="NoSuchValue,#var1#"
> cfsqltype="cf_sql_varchar"
> list="Yes">)
Cheers for the suggestion, but you misunderstand my question.
I'm not
asking for advice how to mask the problem - that's easy
enough - I'm asking
what's *causing* the problem.
Adam