Database schema:
CREATE TABLE Students (
  Student_ID NUMBER PRIMARY KEY,
  First_Name TEXT,
  Middle_Name TEXT,
  Last_Name TEXT,
  Gender_MFU TEXT,
  Student_Address TEXT,
  Email_Adress TEXT,
  Cell_Mobile_Phone TEXT,
  Home_Phone TEXT
);
CREATE TABLE Questions (
  Question_ID NUMBER PRIMARY KEY,
  Type_of_Question_Code TEXT,
  Question_Text TEXT
);
CREATE TABLE Exams (
  Exam_ID NUMBER PRIMARY KEY,
  Subject_Code TEXT,
  Exam_Date TIME,
  Exam_Name TEXT
);
CREATE TABLE Questions_in_Exams (
  Exam_ID NUMBER PRIMARY KEY,
  Question_ID NUMBER,
  FOREIGN KEY (Exam_ID) REFERENCES Exams(Exam_ID),
  FOREIGN KEY (Question_ID) REFERENCES Questions(Question_ID)
);
CREATE TABLE Valid_Answers (
  Valid_Answer_ID NUMBER PRIMARY KEY,
  Question_ID NUMBER,
  Valid_Answer_Text TEXT,
  FOREIGN KEY (Question_ID) REFERENCES Questions(Question_ID)
);
CREATE TABLE Student_Answers (
  Student_Answer_ID NUMBER PRIMARY KEY,
  Exam_ID NUMBER,
  Question_ID NUMBER,
  Student_ID NUMBER,
  Date_of_Answer TIME,
  Comments TEXT,
  Satisfactory_YN TEXT,
  Student_Answer_Text TEXT,
  FOREIGN KEY (Exam_ID) REFERENCES Questions_in_Exams(Exam_ID),
  FOREIGN KEY (Question_ID) REFERENCES Questions_in_Exams(Question_ID),
  FOREIGN KEY (Student_ID) REFERENCES Students(Student_ID)
);
CREATE TABLE Student_Assessments (
  Student_Answer_ID TEXT PRIMARY KEY,
  Valid_Answer_ID NUMBER,
  Student_Answer_Text TEXT,
  Satisfactory_YN TEXT,
  Assessment TEXT,
  FOREIGN KEY (Valid_Answer_ID) REFERENCES Valid_Answers(Valid_Answer_ID)
);

Question: Find the exams whose subject code is not "Database". What are the exam dates and exam names?
SQL: SELECT Exam_Date ,  Exam_Name FROM Exams WHERE Subject_Code != 'Database'

Question: What are the names and dates of the exams with subject code that is not "Database"?
SQL: SELECT Exam_Date ,  Exam_Name FROM Exams WHERE Subject_Code != 'Database'

Question: What is the most common valid answer text?
SQL: SELECT Valid_Answer_Text FROM Valid_Answers GROUP BY Valid_Answer_Text ORDER BY COUNT(*) DESC LIMIT 1

Question: Please show the email addresses of students and the dates of their answers in descending order of dates.
SQL: SELECT T2.Email_Adress ,  T1.Date_of_Answer FROM Student_Answers AS T1 JOIN Students AS T2 ON T1.Student_ID  =  T2.Student_ID ORDER BY T1.Date_of_Answer DESC

Question: Which student answer texts were given both "Normal" and "Absent" as comments?
SQL: SELECT Student_Answer_Text FROM Student_Answers WHERE Comments  =  "Normal" INTERSECT SELECT Student_Answer_Text FROM Student_Answers WHERE Comments  =  "Absent"

Question: Please show the first names of students and the dates of their answers.
SQL: SELECT T2.First_Name ,  T1.Date_of_Answer FROM Student_Answers AS T1 JOIN Students AS T2 ON T1.Student_ID  =  T2.Student_ID

Question: List the dates of the exams with subject code containing the word "data", in descending order of dates.
SQL: SELECT Exam_Date FROM Exams WHERE Subject_Code LIKE '%data%' ORDER BY Exam_Date DESC

Question: Please show the least common assessment for students.
SQL: SELECT Assessment FROM Student_Assessments GROUP BY Assessment ORDER BY COUNT(*) ASC LIMIT 1

Question: What are the distinct student answer texts that received comments "Normal"?
SQL: SELECT DISTINCT Student_Answer_Text FROM Student_Answers WHERE Comments  =  "Normal"

Question: Count the number of different comments for student answers.
SQL: SELECT count(DISTINCT Comments) FROM Student_Answers

Question: What are the last names of the students with gender other than "M"?
SQL: SELECT Last_Name FROM Students WHERE Gender_MFU != "M"

Question: What is al the available information of each student?
SQL: SELECT * FROM Students

Question: List the distinct subject code of exams in ascending alphabetical order .
SQL: select distinct subject_code from exams order by subject_code asc

Question: List the last names of the students whose gender is not "M".
SQL: SELECT Last_Name FROM Students WHERE Gender_MFU != "M"

Question: Which students have 2 or more answer records? Give me their first names.
SQL: SELECT T2.First_Name FROM Student_Answers AS T1 JOIN Students AS T2 ON T1.Student_ID  =  T2.Student_ID GROUP BY T1.Student_ID HAVING COUNT(*)  >=  2

Question: Show the types of questions that have at least three questions.
SQL: SELECT Type_of_Question_Code FROM Questions GROUP BY Type_of_Question_Code HAVING count(*)  >=  3

Question: For each gender, return the gender code and the number of students who identify as that gender.
SQL: SELECT Gender_MFU ,  COUNT(*) FROM Students GROUP BY Gender_MFU

Question: For each question type, return its type code and its count of occurrence.
SQL: SELECT Type_of_Question_Code ,  COUNT(*) FROM Questions GROUP BY Type_of_Question_Code

Question: List the first names of the students who do not have any answers.
SQL: SELECT First_Name FROM Students WHERE Student_ID NOT IN (SELECT Student_ID FROM Student_Answers)

Question: For each student answer, find the email address of the student and the date of the answer. Sort them in descending order of dates.
SQL: SELECT T2.Email_Adress ,  T1.Date_of_Answer FROM Student_Answers AS T1 JOIN Students AS T2 ON T1.Student_ID  =  T2.Student_ID ORDER BY T1.Date_of_Answer DESC

Question: For each student answer, find the first name of the student and the date of the answer.
SQL: SELECT T2.First_Name ,  T1.Date_of_Answer FROM Student_Answers AS T1 JOIN Students AS T2 ON T1.Student_ID  =  T2.Student_ID

Question: Count the number of exams.
SQL: SELECT count(*) FROM Exams

Question: List all the student answer texts in descending order of count.
SQL: SELECT Student_Answer_Text FROM Student_Answers GROUP BY Student_Answer_Text ORDER BY COUNT(*) DESC

Question: Show the student answer texts that received both "Normal" and "Absent" as comments.
SQL: SELECT Student_Answer_Text FROM Student_Answers WHERE Comments  =  "Normal" INTERSECT SELECT Student_Answer_Text FROM Student_Answers WHERE Comments  =  "Absent"

Question: List the last names of the students whose gender is "F" or "M".
SQL: SELECT Last_Name FROM Students WHERE Gender_MFU  =  "F" OR Gender_MFU  =  "M"

Question: How many different comments are there for student answers?
SQL: SELECT count(DISTINCT Comments) FROM Student_Answers

Question: Which students identify their gender as "F" or "M"? Give me their last names.
SQL: SELECT Last_Name FROM Students WHERE Gender_MFU  =  "F" OR Gender_MFU  =  "M"