Solution : https://service.sap.com/sap/support/notes/1257511 (SAP Service marketplace login required)
Key words : 
sap standard environment foreign key-constraints, col1  left outer join table_3, foreign key-constraints, outer joins similar, -ansi outer joins, written abap reports, join table_2, ansi syntax, wrong results, running oracle 10
Related Notes : 
       
| 1165319 | Optimizer merge fix for Oracle 10.2.0.4 |