##### 获得表的字段数量
mysql> select count(1) from information_schema.columns where table_schema = 'mysql' and table_name='user';
+----------+
| count(1) |
+----------+
| 45 |
+----------+
1 row in set (0.00 sec)

mysql>

###########查询服务器是否支持ssl功能
mysql> show variables like 'have_openssl';
+---------------+----------+
| Variable_name | Value |
+---------------+----------+
| have_openssl | DISABLED |
+---------------+----------+
1 row in set, 1 warning (0.01 sec)

mysql>