列出 MySQL 中所有以 have 开头的变量
mysql> show variables like 'have%';
+----------------------+----------+
| Variable_name | Value |
+----------------------+----------+
| have_compress | YES |
| have_crypt | NO |
| have_dynamic_loading | YES |
| have_geometry | YES |
| have_openssl | DISABLED |
| have_profiling | YES |
| have_query_cache | YES |
| have_rtree_keys | YES |
| have_ssl | DISABLED |
| have_symlink | YES |
+----------------------+----------+
10 rows in set (0.04 sec)