Returns 0 rows but which part of the where clause caused it.

I currently have a piece of SQL that will return a row if the input is
valid for the process. My application is a warehouse system. I need to
verify that the thing that is picked for the order can really be used
for that order. It is the correct product, it is in the correct status,
in the correct warehouse, ... Well up until now used one SQL statement
to achieve this. The row was returned or not. If not then the thing
being picked could not be used. Now my boss wants me to return why.
Essentially i will have to get the data and process this in code. Does
anyone have a SQL solution to this? Any tricks anyone uses to determine
which part(s) of the where clause (or join) caused the exclusion?
danWhat if more than 1 condition is FALSE?
There's lots of ways you could implement this, but sooner or later you'll
have to test each condition individually to find the cause.
You could test them up front and not run the query if an "error" condition
is found, or you could run the query and only test the conditions if
@.@.ROWCOUNT = 0.
You could indicate the reason by using RAISERROR, or maintain a table of
error codes and return them in the query, or you could ...
"Dan Holmes" wrote:

> I currently have a piece of SQL that will return a row if the input is
> valid for the process. My application is a warehouse system. I need to
> verify that the thing that is picked for the order can really be used
> for that order. It is the correct product, it is in the correct status,
> in the correct warehouse, ... Well up until now used one SQL statement
> to achieve this. The row was returned or not. If not then the thing
> being picked could not be used. Now my boss wants me to return why.
> Essentially i will have to get the data and process this in code. Does
> anyone have a SQL solution to this? Any tricks anyone uses to determine
> which part(s) of the where clause (or join) caused the exclusion?
> dan
>