Hi,

Some more info on this error, finally this is does not related to merge tables but to remote tables. 
Steps to reproduce:

In one server:
create table lala(sx float, sxx float, sxy float , sy float, syy float, n int);
insert into lala select 13,85,98,15,113,2;

In another remote server:
CREATE REMOTE TABLE fofo(sx FLOAT, sxx FLOAT, sxy FLOAT, sy FLOAT, syy FLOAT, n INT) on 'mapi:monetdb://88.197.53.136:9999/voc10/sys/lala';

CREATE or replace FUNCTION mudf(sx FLOAT, sxx FLOAT, sxy FLOAT, sy FLOAT, syy FLOAT, n INT) 
RETURNS TABLE(res FLOAT)
LANGUAGE PYTHON {
        return 0.5   
};

After that I am getting the following:
sql>select * from mudf((select * from fofo));
(mapi:monetdb://monetdb@88.197.53.136/voc10) Table: missing ‘)'

If I materialise the remote table into a local table, and then use the udf it runs:

sql>create table localtable as select  * from fofo;
operation successful
sql>select * from mudf((select * from localtable));
+--------------------------+
| res                      |
+==========================+
|                      0.5 |
+--------------------------+
1 tuple
sql>

Best,
Yannis

On 16 Sep 2020, at 3:34 PM, Ioannis Foufoulas <johnfouf@di.uoa.gr> wrote:

Hi, we encounter an error when only one table is added to a merge table definition
During a query like "select * from merge table” we get: 
Table: missing ')'"
Probably merge tables cannot contain just one table but the returned error looks like a syntax error.
Some more info to reproduce: the table that has been added to the merge table is a remote table.

Best,
Yannis