Ordinary variables indicated by a prefixed @ sign. : Variable « Select Clause « SQL / MySQL






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

Ordinary variables indicated by a prefixed @ sign.

       
mysql>
They lose their content at the close of the SQL connection.
mysql>
mysql> SET @varname = 3;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT @varname := 3;
+---------------+
| @varname := 3 |
+---------------+
|             3 |
+---------------+
1 row in set (0.00 sec)

SELECT @varname := COUNT(*) FROM table
mysql>
mysql>








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