MariaDB [toyu]> show databases; +--------------------+ | Database | +--------------------+ | ctetinker | | information_schema | | mysql | | performance_schema | | phpmyadmin | | swim | | test | | toyu | +--------------------+ 8 rows in set (0.002 sec) MariaDB [toyu]> SELECT DISTINCT u.user, u.password -> FROM mysql.user AS u -> WHERE u.host = 'localhost'; +------+-------------------------------------------+ | User | Password | +------+-------------------------------------------+ | demo | *C2D24DCA38E9E862098B85BF0AB35CAA52803797 | | pma | | | root | | | yue | *0BE23F42F79ABCFD46E7AF357A07122B6C495EA8 | +------+-------------------------------------------+ 4 rows in set (0.026 sec) MariaDB [toyu]> SELECT table_name, table_type, row_format, table_rows, avg_row_length -> FROM information_schema.tables -> WHERE table_schema = 'information_schema' -> ORDER BY table_name DESC; +---------------------------------------+-------------+------------+------------+----------------+ | table_name | table_type | row_format | table_rows | avg_row_length | +---------------------------------------+-------------+------------+------------+----------------+ | VIEWS | SYSTEM VIEW | Page | NULL | 0 | | user_variables | SYSTEM VIEW | Fixed | NULL | 6630 | | USER_STATISTICS | SYSTEM VIEW | Fixed | NULL | 567 | | USER_PRIVILEGES | SYSTEM VIEW | Fixed | NULL | 2314 | | TRIGGERS | SYSTEM VIEW | Page | NULL | 0 | | TABLE_STATISTICS | SYSTEM VIEW | Fixed | NULL | 1181 | | TABLE_PRIVILEGES | SYSTEM VIEW | Fixed | NULL | 2700 | | TABLE_CONSTRAINTS | SYSTEM VIEW | Fixed | NULL | 2504 | | TABLESPACES | SYSTEM VIEW | Fixed | NULL | 6951 | | TABLES | SYSTEM VIEW | Fixed | NULL | 14841 | | SYSTEM_VARIABLES | SYSTEM VIEW | Page | NULL | 0 | | STATISTICS | SYSTEM VIEW | Fixed | NULL | 5753 | | SQL_FUNCTIONS | SYSTEM VIEW | Fixed | NULL | 194 | | SPATIAL_REF_SYS | SYSTEM VIEW | Fixed | NULL | 7691 | | SESSION_VARIABLES | SYSTEM VIEW | Fixed | NULL | 6340 | | SESSION_STATUS | SYSTEM VIEW | Fixed | NULL | 6340 | | SCHEMA_PRIVILEGES | SYSTEM VIEW | Fixed | NULL | 2507 | | SCHEMATA | SYSTEM VIEW | Fixed | NULL | 3464 | | ROUTINES | SYSTEM VIEW | Page | NULL | 0 | | REFERENTIAL_CONSTRAINTS | SYSTEM VIEW | Fixed | NULL | 4814 | | PROFILING | SYSTEM VIEW | Fixed | NULL | 308 | | PROCESSLIST | SYSTEM VIEW | Page | NULL | 0 | | PLUGINS | SYSTEM VIEW | Page | NULL | 0 | | PARTITIONS | SYSTEM VIEW | Page | NULL | 0 | | PARAMETERS | SYSTEM VIEW | Page | NULL | 0 | | OPTIMIZER_TRACE | SYSTEM VIEW | Page | NULL | 0 | | KEY_COLUMN_USAGE | SYSTEM VIEW | Fixed | NULL | 4637 | | KEY_CACHES | SYSTEM VIEW | Fixed | NULL | 659 | | KEYWORDS | SYSTEM VIEW | Fixed | NULL | 194 | | INNODB_TRX | SYSTEM VIEW | Fixed | NULL | 4530 | | INNODB_TABLESPACES_SCRUBBING | SYSTEM VIEW | Fixed | NULL | 2020 | | INNODB_TABLESPACES_ENCRYPTION | SYSTEM VIEW | Fixed | NULL | 2012 | | INNODB_SYS_VIRTUAL | SYSTEM VIEW | Fixed | NULL | 17 | | INNODB_SYS_TABLESTATS | SYSTEM VIEW | Fixed | NULL | 1215 | | INNODB_SYS_TABLESPACES | SYSTEM VIEW | Fixed | NULL | 2102 | | INNODB_SYS_TABLES | SYSTEM VIEW | Fixed | NULL | 2060 | | INNODB_SYS_SEMAPHORE_WAITS | SYSTEM VIEW | Fixed | NULL | 60189 | | INNODB_SYS_INDEXES | SYSTEM VIEW | Fixed | NULL | 618 | | INNODB_SYS_FOREIGN_COLS | SYSTEM VIEW | Fixed | NULL | 1748 | | INNODB_SYS_FOREIGN | SYSTEM VIEW | Fixed | NULL | 1752 | | INNODB_SYS_FIELDS | SYSTEM VIEW | Fixed | NULL | 594 | | INNODB_SYS_DATAFILES | SYSTEM VIEW | Fixed | NULL | 12007 | | INNODB_SYS_COLUMNS | SYSTEM VIEW | Fixed | NULL | 610 | | INNODB_MUTEXES | SYSTEM VIEW | Fixed | NULL | 24017 | | INNODB_METRICS | SYSTEM VIEW | Fixed | NULL | 3003 | | INNODB_LOCK_WAITS | SYSTEM VIEW | Fixed | NULL | 599 | | INNODB_LOCKS | SYSTEM VIEW | Fixed | NULL | 31244 | | INNODB_FT_INDEX_TABLE | SYSTEM VIEW | Fixed | NULL | 1054 | | INNODB_FT_INDEX_CACHE | SYSTEM VIEW | Fixed | NULL | 1054 | | INNODB_FT_DELETED | SYSTEM VIEW | Fixed | NULL | 9 | | INNODB_FT_DEFAULT_STOPWORD | SYSTEM VIEW | Fixed | NULL | 56 | | INNODB_FT_CONFIG | SYSTEM VIEW | Fixed | NULL | 1163 | | INNODB_FT_BEING_DELETED | SYSTEM VIEW | Fixed | NULL | 9 | | INNODB_CMP_RESET | SYSTEM VIEW | Fixed | NULL | 25 | | INNODB_CMP_PER_INDEX_RESET | SYSTEM VIEW | Fixed | NULL | 1755 | | INNODB_CMP_PER_INDEX | SYSTEM VIEW | Fixed | NULL | 1755 | | INNODB_CMPMEM_RESET | SYSTEM VIEW | Fixed | NULL | 29 | | INNODB_CMPMEM | SYSTEM VIEW | Fixed | NULL | 29 | | INNODB_CMP | SYSTEM VIEW | Fixed | NULL | 25 | | INNODB_BUFFER_POOL_STATS | SYSTEM VIEW | Fixed | NULL | 257 | | INNODB_BUFFER_PAGE_LRU | SYSTEM VIEW | Fixed | NULL | 6669 | | INNODB_BUFFER_PAGE | SYSTEM VIEW | Fixed | NULL | 6852 | | INDEX_STATISTICS | SYSTEM VIEW | Fixed | NULL | 1743 | | GLOBAL_VARIABLES | SYSTEM VIEW | Fixed | NULL | 6340 | | GLOBAL_STATUS | SYSTEM VIEW | Fixed | NULL | 6340 | | GEOMETRY_COLUMNS | SYSTEM VIEW | Fixed | NULL | 4244 | | FILES | SYSTEM VIEW | Fixed | NULL | 4022 | | EVENTS | SYSTEM VIEW | Page | NULL | 0 | | ENGINES | SYSTEM VIEW | Fixed | NULL | 731 | | ENABLED_ROLES | SYSTEM VIEW | Fixed | NULL | 387 | | COLUMN_PRIVILEGES | SYSTEM VIEW | Fixed | NULL | 2893 | | COLUMNS | SYSTEM VIEW | Page | NULL | 0 | | COLLATION_CHARACTER_SET_APPLICABILITY | SYSTEM VIEW | Fixed | NULL | 195 | | COLLATIONS | SYSTEM VIEW | Fixed | NULL | 231 | | CLIENT_STATISTICS | SYSTEM VIEW | Fixed | NULL | 386 | | CHECK_CONSTRAINTS | SYSTEM VIEW | Page | NULL | 0 | | CHARACTER_SETS | SYSTEM VIEW | Fixed | NULL | 384 | | APPLICABLE_ROLES | SYSTEM VIEW | Fixed | NULL | 979 | | ALL_PLUGINS | SYSTEM VIEW | Page | NULL | 0 | +---------------------------------------+-------------+------------+------------+----------------+ 79 rows in set (0.089 sec) MariaDB [toyu]> MariaDB [toyu]> SELECT table_name, table_type, row_format, table_rows, avg_row_length -> FROM information_schema.tables -> WHERE table_schema = 'toyu' -> ORDER BY table_name ASC; +------------+------------+------------+------------+----------------+ | table_name | table_type | row_format | table_rows | avg_row_length | +------------+------------+------------+------------+----------------+ | class | BASE TABLE | Dynamic | 14 | 1170 | | course | BASE TABLE | Dynamic | 11 | 1489 | | department | BASE TABLE | Dynamic | 7 | 2340 | | enroll | BASE TABLE | Dynamic | 22 | 744 | | faculty | BASE TABLE | Dynamic | 11 | 1489 | | grade | BASE TABLE | Dynamic | 15 | 1092 | | school | BASE TABLE | Dynamic | 4 | 4096 | | student | BASE TABLE | Dynamic | 11 | 1489 | +------------+------------+------------+------------+----------------+ 8 rows in set (0.001 sec) MariaDB [toyu]> MariaDB [toyu]> SELECT COUNT(*) AS `# RC` -> FROM information_schema.Referential_constraints AS is -> WHERE is.constraint_schema = 'toyu'; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'is WHERE is.constraint_schema = 'toyu'' at line 2 MariaDB [toyu]> SELECT COUNT(*) AS `# RC` -> FROM information_schema.Referential_constraints AS IRC -> WHERE IRC.constraint_schema = 'toyu'; +------+ | # RC | +------+ | 11 | +------+ 1 row in set (0.004 sec) MariaDB [toyu]> SELECT t.TABLE_SCHEMA AS `schema`, COUNT(t.TABLE_NAME) AS num_tables -> FROM information_schema.tables AS t -> GROUP BY `schema` -> ORDER BY num_tables DESC; +--------------------+------------+ | schema | num_tables | +--------------------+------------+ | information_schema | 79 | | performance_schema | 52 | | mysql | 31 | | phpmyadmin | 19 | | swim | 13 | | toyu | 8 | +--------------------+------------+ 6 rows in set (0.007 sec) MariaDB [toyu]> notee