MySQL中的运算符

mysql> select 0.1+0.3333, 0.1-0.3333, 0.1*0.3333, 1/2, 1%2;
+------------+------------+------------+--------+------+
| 0.1+0.3333 | 0.1-0.3333 | 0.1*0.3333 | 1/2    | 1%2  |
+------------+------------+------------+--------+------+
|     0.4333 |    -0.2333 |    0.03333 | 0.5000 |    1 |
+------------+------------+------------+--------+------+
1 row in set (0.01 sec)

mysql> select 1=0, 1=1, NULL=NULL;
+-----+-----+-----------+
| 1=0 | 1=1 | NULL=NULL |
+-----+-----+-----------+
|   0 |   1 |      NULL |
+-----+-----+-----------+
1 row in set (0.00 sec)

mysql> select 1<>0, 1<>1, null<>null;
+------+------+------------+
| 1<>0 | 1<>1 | null<>null |
+------+------+------------+
|    1 |    0 |       NULL |
+------+------+------------+
1 row in set (0.00 sec)

mysql> select 1<=>0, 1<=>1, NULL<=>NULL;
+-------+-------+-------------+
| 1<=>0 | 1<=>1 | NULL<=>NULL |
+-------+-------+-------------+
|     0 |     1 |           1 |
+-------+-------+-------------+
1 row in set (0.00 sec)

mysql> select 10 between 10 and 20, 9 between 10 and 20;
+----------------------+---------------------+
| 10 between 10 and 20 | 9 between 10 and 20 |
+----------------------+---------------------+
|                    1 |                   0 |
+----------------------+---------------------+
1 row in set (0.01 sec)

mysql> select 'abcdef' regexp 'ab', 'abcdefg' regexp 'k';
+----------------------+----------------------+
| 'abcdef' regexp 'ab' | 'abcdefg' regexp 'k' |
+----------------------+----------------------+
|                    1 |                    0 |
+----------------------+----------------------+
1 row in set (0.00 sec)

mysql> select not 0, not 1, not null;
+-------+-------+----------+
| not 0 | not 1 | not null |
+-------+-------+----------+
|     1 |     0 |     NULL |
+-------+-------+----------+
1 row in set (0.00 sec)

mysql> select (1 and 1), (0 and 1), (3 and 1), (1 and null);
+-----------+-----------+-----------+--------------+
| (1 and 1) | (0 and 1) | (3 and 1) | (1 and null) |
+-----------+-----------+-----------+--------------+
|         1 |         0 |         1 |         NULL |
+-----------+-----------+-----------+--------------+
1 row in set (0.00 sec)

mysql> select (1 or 0), (0 or 0), (1 or null), (1 or 1), (null or null);
+----------+----------+-------------+----------+----------------+
| (1 or 0) | (0 or 0) | (1 or null) | (1 or 1) | (null or null) |
+----------+----------+-------------+----------+----------------+
|        1 |        0 |           1 |        1 |           NULL |
+----------+----------+-------------+----------+----------------+
1 row in set (0.00 sec)

mysql> select 1 xor 1, 0 xor 0, 1 xor 0, 0 xor 1, null xor 1;
+---------+---------+---------+---------+------------+
| 1 xor 1 | 0 xor 0 | 1 xor 0 | 0 xor 1 | null xor 1 |
+---------+---------+---------+---------+------------+
|       0 |       0 |       1 |       1 |       NULL |
+---------+---------+---------+---------+------------+
1 row in set (0.00 sec)

mysql> select 2&3;
+-----+
| 2&3 |
+-----+
|   2 |
+-----+
1 row in set (0.00 sec)

mysql> select 2|3;
+-----+
| 2|3 |
+-----+
|   3 |
+-----+
1 row in set (0.00 sec)

mysql> select 100>>3;
+--------+
| 100>>3 |
+--------+
|     12 |
+--------+
1 row in set (0.00 sec)