I just had to make a triple union (= 3 select statements) which gave me this error message:
Dynamic SQL Error
-SQL error code = -104
-Invalid command
-Data type unknown
Each on its own, the 3 SQL statements worked fine. Also combining the first and second worked.
The 3rd one contained an additional constant string..
The SQL statements are in the box below.. once I added the CAST (expression AS CHAR(128)), it worked.
The puzzling thing is that select statements 1 and 2 already contained those string constants 'P_' and '_A_'... so why would the union of those two work without a cast? Questions over questions, but the triple union below needs the casts - then it works.
select cast (upper('P_' || p.name || '_A_' || a.name) as char(128)) as fname
[..]
union
select cast (upper('P_' || p.name || '_A_' || a.name) as char(128)) as fname
[..]
union
select cast (upper('P_' || p.name || '_A_' || 'World') as char(128)) as fname
[..]