Mega Code Archive
UPDATE statement moves each bit to the left one position
<![CDATA[
mysql>
mysql> CREATE TABLE Attributes
-> (
-> UserID SMALLINT NOT NULL PRIMARY KEY,
-> Settings TINYINT UNSIGNED NOT NULL
-> );
Query OK, 0 rows affected (0.01 sec)
mysql> INSERT INTO Attributes VALUES
-> (101, 58),
-> (102, 73),
-> (103, 45);
Query OK, 3 rows affected (0.00 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql>
mysql> select * from Attributes;
+--------+----------+
| UserID | Settings |
+--------+----------+
| 101 | 58 |
| 102 | 73 |
| 103 | 45 |
+--------+----------+
3 rows in set (0.00 sec)
mysql>
mysql> UPDATE Attributes
-> SET Settings=Settings << 1;
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0
mysql>
mysql>
mysql> select * from Attributes;
+--------+----------+
| UserID | Settings |
+--------+----------+
| 101 | 116 |
| 102 | 146 |
| 103 | 90 |
+--------+----------+
3 rows in set (0.00 sec)
mysql>
mysql> drop table Attributes;
Query OK, 0 rows affected (0.00 sec)
mysql>
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