como formular una consulta omitiendo los resultados repetidos

[leonardo_josue]

Hola SirDuque:

Puedes utilizar la cláusula HAVING y el GROUP BY

Código MySQL:

mysql> create table TuTabla (cliente int, articulo int);
Query OK, 0 rows affected (0.06 sec)
 
mysql> insert into TuTabla values (1, 12),(1, 12),(2, 13),
    -> (3, 15),(4, 16);
Query OK, 5 rows affected (0.02 sec)
Records: 5  Duplicates: 0  Warnings: 0
 
mysql> select * from TuTabla;
+---------+----------+
| cliente | articulo |
+---------+----------+
|       1 |       12 |
|       1 |       12 |
|       2 |       13 |
|       3 |       15 |
|       4 |       16 |
+---------+----------+
5 rows in set (0.00 sec)
 
mysql> select cliente, articulo from TuTabla
    -> GROUP BY cliente, articulo
    -> HAVING count(*) = 1;
+---------+----------+
| cliente | articulo |
+---------+----------+
|       2 |       13 |
|       3 |       15 |
|       4 |       16 |
+---------+----------+
3 rows in set (0.00 sec)
 

Saludos
Leo