In Oracle, you can use a SELECT subquery without specifying an alias. In MariaDB you have to specify aliases for subqueries in SELECT statements.
Oracle:
-- No alias in subquery SELECT * FROM (SELECT * FROM cities); # Ok -- Alias 't' is specified (it is optional) SELECT * FROM (SELECT * FROM cities) t; # Ok
MariaDB:
-- No alias in subquery (error) SELECT * FROM (SELECT * FROM cities); # ERROR 1064 (42000): You have an error in your SQL syntax; # check the manual for the right syntax to use near '' at line 3 -- Alias 't' is specified SELECT * FROM (SELECT * FROM cities) t; # Ok
For more information, see Oracle to MariaDB Migration.