四种mysql注释实例
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2022-05-06 20:44:01
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mysql注释方法一:使用#
mysql>
mysql> SELECT 1+1; # This comment continues to the end of line
+-----+
| 1+1 |
+-----+
| 2 |
+-----+
1 row in set (0.00 sec)
mysql>
mysql注释方法二:使用--
mysql>
mysql> SELECT 1+1; -- This comment continues to the end of line
+-----+
| 1+1 |
+-----+
| 2 |
+-----+
1 row in set (0.00 sec)
mysql注释方法三:使用/* */
mysql>
mysql>
mysql> SELECT 1 /* this is an in-line comment */ + 1;
+---------+
| 1 + 1 |
+---------+
| 2 |
+---------+
1 row in set (0.00 sec)
mysql> SELECT 1+
-> /*
/*> this is a
/*> multiple-line comment
/*> */
-> 1;
+-------+
| 1+
1 |
+-------+
| 2 |
+-------+
1 row in set (0.00 sec)
mysql>
mysql注释方法四:使用/*! */
mysql>
mysql>
mysql> CREATE /*!32302 TEMPORARY */ TABLE t (a INT);
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql> desc t;
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| a | int(11) | YES | | NULL | |
+-------+---------+------+-----+---------+-------+
1 row in set (0.00 sec)
mysql>
mysql>
mysql> drop table t;
Query OK, 0 rows affected (0.00 sec)
mysql>
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