查询mysql版本号
mysql> select version();
+------------+
| version() |
+------------+
| 5.7.23-log |
+------------+
1 row in set (0.12 sec)
mysql> select version();
+------------+
| version() |
+------------+
| 5.7.23-log |
+------------+
1 row in set (0.12 sec)