The isConjunated property for a SysML Proxy port is held in the t_xref table as shown below
XrefID,Name,Type,Visibility,Namespace,Requirement,Constraint,Behavior,Partition,Description,Client,Supplier,Link,
{5D9468D5-BCF2-4af7-9C8F-540F9821D148},CustomProperties,element property,Public, , , , ,0,@PROP=@NAME=isConjugated@ENDNAME;@TYPE=Boolean@ENDTYPE;@VALU=-1@ENDVALU;@PRMT=@ENDPRMT;@ENDPROP;,{03F5F125-4CED-4bb1-B65B-29DB688BD257},<none>, ,
#
The field containing the isConjugated value is Description the full value of which is
@PROP=@NAME=isConjugated@ENDNAME;@TYPE=Boolean@ENDTYPE;@VALU=-1@ENDVALU;@PRMT=@ENDPRMT;@ENDPROP;
The link to the t_object table is Client and contains guid of the object
This should give you enough info to contstruct the SQL query most likely joining t_object and t_xref and restricting the search to the value of the description in t_xref
Something like
SELECT t_object.ea_guid, t_object.Name
FROM t_object, t_xref
WHERE t_object.ea_guid = t_xref.Client
AND t_xref.Description = '@PROP=@NAME=isConjugated@ENDNAME;@TYPE=Boolean@ENDTYPE;@VALU=-1@ENDVALU;@PRMT=@ENDPRMT;@ENDPROP;'
Hope this helps
Phil