jt400 Trunc my where condition as like clause - jt400

Question

I'm using jt400-9.3.jar to connect DB2/AS400.
My table BAND with this records:
+-----|------------------+
| MAT | NAME |
+-----|------------------+
|100 | Paul McCartney |
|101 | John Lennon |
|102 | Ringo Starr |
|103 | George Harrison |
And my table MUSICIAN with:
+------|------------------+
|MAT | NAME |
+------|------------------+
|1001 | Pete Best |
|1002 | Stuart Sutcliffe |
|1003 | Jimmy Nicol |
|1004 | Tommy Moore |
|1005 | Norman Chapman |
When I run this select
SELECT t.mt, t.name
FROM (
SELECT
trim(b.mat) AS mat,
trim(b.name) AS name
FROM band b
WHERE trim(b.mat) = '1001'
UNION
SELECT
trim(m.mat) AS mat,
trim(m.name) AS name
FROM MUSICIAN m
WHERE trim(m.mat) = '1001'
) AS t
FETCH FIRST 1 ROWS ONLY
I retrieve:
+-----|----------------+
|MAT |NAME |
+-----|----------------+
|100 | Paul McCartney |
The first query is working as like clause. The 1001 is matching with 100, but the sentence is = no like.
When I execute the query in dbeaver works, but in java (using PreparedStatement) I got the wrong, there are some configuration to the driver?

Answer 1

John Eberhard answer so fast about the problem for me.
https://sourceforge.net/p/jt400/bugs/121/
Registering your answer.
The problem is that = is being used in the query. Because = is used in
the query, then the database tells the driver that the type is
CHAR(5). The driver then truncates to char 5.
There are two possible solutions.
Add a cast to the parameter marker so that the larger character will fit and miscompare.
i.e. SELECT * FROM MYTABLE WHERE MAT = CAST( ? AS VARCHAR(80))
Use the "query replace truncated parameter" JDBC property. See https://static.javadoc.io/net.sf.jt400/jt400/9.7/com/ibm/as400/access/doc-files/JDBCProperties.html
Here is how that property is defined.
"query replace truncated parameter"
Specifies the value that should be used in place of a truncated
parameter of an SQL query. By default, the parameter is silently
truncated to the length for the parameter. Consider the following
scenario.
Table T1 has a CHAR(3) column with the name of C1, and a row where
C1='ABC'. An application prepares a statement using SELECT * FROM
TABLE_X where C1=? If the parameter is set to 'ABCD', it wil be
silently truncated to 'ABC' and a row will be returned by the query.
This property avoids this problem by allowing the application to set
the string to something that doesn't exist in the application - i.e.
#######. A blank value means that the property will be ignored.