Use of Input Variables in SQL-Queries Sometimes Not Possible

Question

Only in simple SELECT-statements the use of input variables ([%0], [%1], etc.) work without problems.
In more complex queries the use of these variables is not possible (e.g. SELECT-statements with sub-queries, sometimes when UNION is used - but I couldn't find any general rule when the problems will arise; sometimes two different queries with the same query-structure behave in different ways when these variables are used).
In these cases the query is not executed - not even the input-window to enter values into the input variables is displayed. The query stops with some strange error-messages in the status line. These error-messages doesn't have any relation to the actual query - sometimes it refers to field-names never used in the query or refers to syntax error which do not exist.
If the input variables are replaced by constant values there are no problems so there can't be any syntax errors - the only difference is the presence or absence of input variables.
Example:
  provided that the queries have a certain complexity
  SELECT ...
  FROM   ... OINV Tx ...
  WHERE  ... Tx.DocDate >= [%0] ...
  does not work,
  SELECT ...
  FROM   ... OINV Tx ...
  WHERE  ... Tx.DocDate >= '1.1.2007' ...
  works!
Does anybody have run into the same problem and now if it is a bug of SAP-BO or an error on behalf of the user? Does anybody know a way to correct the problem?
Thanks in advance!
Frank
By the way: Are there any rules where exactly input variables can be used in a query?
Only in SELECT-statements? Where there exactly?
In statements outside of SELECT?

Answer 1

Only SAP Partners Can access service.sap.com/notes, but I think it is possible to search in them from the customer portal as well.
Here are summary of the two notes mentioned before this:
730960:
<i>
The following query is an example for how to define variables in long
queries rather than using "Fixed Declares".
You need to use exactly the same template as follows, do not delete
"comments" from this query.
The only changes you need to do :
1. In the first and in the fifth rows you need to select the table to which you would like to relate the variable e.g. in this example, the variable is related to the table VPM1 - 'Payments to Vendors - Rows'.
2. In the fourth and in the eighth rows you need to select the field to which you would like to define the variables e.g. in this example, the variable is the field 'DueDate'.
/SELECT FROM [dbo].[VPM1] T0/
declare  @fromdate as datetime
/* WHERE */
set @fromdate = /* T0.DueDate */ '[%0]'
/SELECT FROM [dbo].[VPM1] T1/
declare  @tilldate as datetime
/* WHERE */
set @tilldate = /* T0.DueDate */ '[%1]'
select  OVPM.docnum, VPM1.dueDate,VPM1.CheckNum, VPM1.Branch,
VPM1.BankCode, VPM1.CheckSum, OVPM.CardName,
case
when OPCH.docnum is null then VPM2.docEntry
else OPCH.docnum
end as 'docnum'
from OVPM INNER join VPM1 on OVPM.docnum = VPM1.docnum
left join  VPM2 LEFT JOIN OPCH ON VPM2.DocEntry = OPCH.DocEntry
on OVPM.docnum = VPM2.docnum
where OVPM.Canceled = 'N' AND VPM1.DueDate >=@fromdate AND
VPM1.DueDate <=@tilldate
</i>
955295:
<i>
Using SAP Business One Survey Variables (parameters) in a 'Set' SQL Statement can give an error in the Query Generator.
For Example:
Declare @Num as numeric(2)
Set @Num = [%0]
Select T0.DocNum
From ORDR T0
Where DocNum = @Num
Other terms
query, SQL, parameter, survey, variable, query generator, set, declare, [%0], table, error, SAP Business One
Reason and Prerequisites
FAQ
Solution
In such cases you need to put in an SQL remark statement a reference field in the DB for the Survey Variable (any field).
For Example: (to make the above query work)
Declare @Num as numeric(2)
Set @Num = /* T0.DocNum */ [%0]
Select T0.DocNum
From ORDR T0
Where docnum = @Num
</i>