In "personal" table, there are 6 columns named id, name, percentage, age, gender, city. In "personal" table, column name "id" is PRIMARY KEY and column name "city" is FOREIGN KEY. In "courses" table, there are 2 columns named course_id and course_name. In "courses" table, column name "course_id" is PRIMARY KEY. In "city" table, there are 2 columns named cid and cityname. In "city" table, column name "cid" is PRIMARY KEY. In "lecturers" table, there are 6 columns named id, name, percentage, age, gender, id_of_personal. In "lecturers" table, column name "id" is PRIMARY KEY and column name "id_of_personal" is FOREIGN KEY. UNION and UNION ALL Syntax : SELECT column1, column2 FROM table1 UNION/UNION ALL SELECT column1, column2 FROM table2; RULES : 1) Each SELECT statement within UNION must have the same number of columns. 2) The columns must also have ...
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