Inserting name values into the multisequence table generates separate sequences for each distinct name: : Distinct « Select Clause « SQL / MySQL






  1. SQL / MySQL
  2. Select Clause
  3. Distinct

Inserting name values into the multisequence table generates separate sequences for each distinct name:

       
mysql>
mysql> CREATE TABLE multisequence
    -> (
    ->     name     CHAR(10) NOT NULL,
    ->     name_id  INT UNSIGNED NOT NULL AUTO_INCREMENT,
    ->     PRIMARY KEY (name, name_id)
    -> );
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> INSERT INTO multisequence (name) VALUES('Petr'),('Ilya'),('Ilya'),('Yuri'),('Ilya'),('Petr');
Query OK, 6 rows affected (0.00 sec)
Records: 6  Duplicates: 0  Warnings: 0

mysql>
mysql> SELECT * FROM multisequence ORDER BY name, name_id;
+------+---------+
| name | name_id |
+------+---------+
| Ilya |       1 |
| Ilya |       2 |
| Ilya |       3 |
| Petr |       1 |
| Petr |       2 |
| Yuri |       1 |
+------+---------+
6 rows in set (0.00 sec)

mysql>
mysql> drop table multisequence;
Query OK, 0 rows affected (0.00 sec)








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