mysql函数中打印信息_mysql信息函数
mysql> SELECT CONNECTION_ID(); #当前连接的ID
+-----------------+
| CONNECTION_ID() |
+-----------------+
| 1 |
+-----------------+
1 row in set (0.00 sec)
mysql> SELECT DATABASE(); #当前打开的数据库
+------------+
| DATABASE() |
+------------+
| test |
+------------+
mysql> SHOW COLUMNS FROM test; #
+----------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+---------------------+------+-----+---------+----------------+
| id | tinyint(3) unsigned | NO | PRI | NULL |auto_increment|
| username | varchar(20) | YES | | NULL | |
+----------+---------------------+------+-----+---------+----------------+
mysql>INSERT test VALUES(NULL,Mary), (NULL, H);
Query OK, 2 rows affected (0.02 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> SELECT * FROM test;
+----+----------+
| id | username |
+----+----------+
| 1 | John |
| 2 | Mary |
| 3 | 1%Lily |
| 4 | Rose |
| 5 | NULL |
| 6 | Mary |
| 7 | Mary |
| 8 | H |
+----+----------+
8 rows in set (0.00 sec)
mysql>SELECT LAST_INSERT_ID(); #最后插入记录的ID号(数据表中必须存在自动编号的字段，字段名不一定为id)
+------------------+
| LAST_INSERT_ID() |
+------------------+
| 7 |
+------------------+
1 row in set (0.00 sec)
mysql> SELECT USER(); #打印当前登录的用户
+----------------+
| USER() |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.01 sec)
mysql>SELECT VERSION(); #打印mysql版本的信息
+-----------+
| VERSION() |
+-----------+
| 5.5.54 |
+-----------+
mysql> SELECT CONNECTION_ID(); #当前连接的ID +-----------------+ | CONNECTION_ID() | +-----------------+ | 1 | +-----------------+ 1 row in set (0.00 sec) mysql> SELECT DATABASE(); #当前打开的数据库 +------------+ | DATABASE() | +------------+ | test | +------------+ mysql> SHOW COLUMNS FROM test; # +----------+---------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+---------------------+------+-----+---------+----------------+ | id | tinyint(3) unsigned | NO | PRI | NULL |auto_increment| | username | varchar(20) | YES | | NULL | | +----------+---------------------+------+-----+---------+----------------+ mysql>INSERT test VALUES(NULL,Mary), (NULL, H); Query OK, 2 rows affected (0.02 sec) Records: 2 Duplicates: 0 Warnings: 0 mysql> SELECT * FROM test; +----+----------+ | id | username | +----+----------+ | 1 | John | | 2 | Mary | | 3 | 1%Lily | | 4 | Rose | | 5 | NULL | | 6 | Mary | | 7 | Mary | | 8 | H | +----+----------+ 8 rows in set (0.00 sec) mysql>SELECT LAST_INSERT_ID(); #最后插入记录的ID号(数据表中必须存在自动编号的字段，字段名不一定为id) +------------------+ | LAST_INSERT_ID() | +------------------+ | 7 | +------------------+ 1 row in set (0.00 sec) mysql> SELECT USER(); #打印当前登录的用户 +----------------+ | USER() | +----------------+ | root@localhost | +----------------+ 1 row in set (0.01 sec) mysql>SELECT VERSION(); #打印mysql版本的信息 +-----------+ | VERSION() | +-----------+ | 5.5.54 | +-----------+