I use OOo2.0.3rc4de.

I want to show the whole record in a list box, but link to the primary key.
Therefore I use a query as datasource, which has the concatenated record in the
first column and the primary key in the second record. I tried this versions
(1) with function CONCAT, parsed SQL
SELECT CONCAT( CONCAT( CONCAT( CONCAT( "ID", ' | ' ), "Lehrer" ), ' | ' ),
"Raum" ) AS "info", "ID" FROM "Klassen" "Klassen"
(2) with + , parsed SQL
SELECT "ID" + ( ' | ' ) + "Lehrer" + ( ' | ' ) + "Raum" AS "info", "ID" FROM
"Klassen" "Klassen"
(3) same as (2), native SQL

Version (2) doesn't show the "info" column in the listbox, although all three
queries show the same table, when you run them as query.
Try the forms in the attached testbase.