Chapter Eight Data Manipulation Language (DML) Objectives Oracle DBMS Understanding the DML General format of SQL Capability of SELECT statement Use of Operators String Processing Concept of NULL Conditional Statement

2 SQL Structured Query Language Developed by IBM Used in most Commercial DBMS Statements are not case sensitive. Statements can be on one or more lines. Reserved words cannot be abbreviated or split over lines. Terminated with a semicolon. Statements are entered at SQL prompt. The subsequent lines are numbered (SQL buffer) Only one statement can be current at any time in the buffer.

3 Example: Student(Name, ID, GPA, Major, B_Date) Course(C_Num, Dept, Title, Cr) Student_Course(ID, C_Num, Dept, Grade) Faculty(ID, Name, Dept, Salary, Area) Faculty_Course(ID, C_Num, Dept, Semester) Department(Name, Num_Faculty) Tables

4 General Format SELECT fieldnames FROM relation [ WHERE condition] [ GROUP BY group_field ] [ HAVING condition] [ ORDER BY fieldname] ;

5 Select Attributes: Example: Show the name and GPA of the students (ALL). SELECT name, GPA FROMstudent;

6 Select Attributes: Example: List all the columns in course SELECT* FROMcourse;

7 General Format Table display: Default justification: -Date and charactersLEFT -NumberRIGHT Default display: -Uppercase

8 General Format NAMEGPA MARY 3.1

9 Duplicated Rows Example: List of the course credits offered at FSU. SELECT Cr FROMCourse;

10 Use of Distinct: Example: Type of the course credits offered at FSU. SELECT DISTinct Cr FROMCourse;

11 Use of Aliases: Example: List of the faculty ’ s name and their salary per month. SELECT name, salary / 12 FROM faculty;

12 Use of Aliases: Rename column heading Example: List of the faculty salary for next year with 5% increase. SELECT name, salary Pay, salary+salary*0.05 AS New_Salary FROM faculty;

13 Use of Arithmetic Operations: () -, *, / +, - Operation of some priority is evaluated from left to right 5* (2+1)

14 Use of Arithmetic Operations: Example: List the course numbers and credits in a quarter system SELECTC_Num, Cr * 0.75 FROMCourse;

15 Use of Concatenation: Example: List of faculty and department as a unit SELECTname || dept “ Name: ” FROM faculty; Name: CHITSAZCOSC

16 Use of Literal: Example: List of faculty and department SELECTname || ‘ ‘ || ‘ is in ’ || dept “ Department Name: ” FROM faculty; Department Name: CHITSAZ is in COSC

17 Condition statements: SELECTname, GPA FROMstudent WHEREGPA > 2;

18 Condition Operators: =, >, >=, != ^= IN BETWEEN..... AND..... LIKE IS NULL AND, OR, NOT

19 String & Date Comparison Example: List the students who born on March 2, 99 SELECTname FROMstudent WHEREB_Date = ’ 02-MAR-99 ’ ; Date Format ‘ DD-MON-YY ’

20 Use of Boolean Operations: Example: List of Student names that have a GPA > 3 and majoring in COSC SELECTname FROMstudent WHEREGPA > 3 AND major = 'COSC'; Character string is case sensitive & should be in a single quotation mark

21 Precedence Rule: >, >=, <>, <=, =, NOT AND OR

22 Null vs. No Value Null value is: Unavailable Unassigned Unknown Inapplicable Examples: Null is not the same as zero or blank

23 Null vs. No Value SELECTname, Major FROMStudent; SELECTname, Num_Faculty FROMDepartment;

24 Null Values in Expressions Result of an arithmetic expression with a null value is null. SELECTname, GPA*0.75 FROMStudent;

25 Null vs. No Value List of students with no major SELECTname FROMStudent WHEREmajor IS NULL; SELECTname FROMStudent WHEREmajor IS NOT NULL;

26 Null vs. No Value NVL Null Value substitution: We can substitute a value for a NULL value record by using NVL. List of students and their major: SELECTname, NVL(major, ‘unknown’) FROMStudent; SELECT name, NVL(GPA, 0.0) FROM Student; *COALESCE

27 Null vs. No Value List of students and their GPA base 20 points: SELECT name, NVL(GPA, 0.0)*5 FROM Student; NVL2 (Exp1, Exp2, Exp3)

28 Use of Between BETWEEN: Test against a list of values: (Check the data in a range) List description of courses with the course number between 200 AND 299 SELECTTitle FROMCourse WHEREC_Num BETWEEN 200 AND 299;

29 Use of Between SELECTTitle FROMCourse WHERE C_Num NOT (BETWEEN 200 AND 299); SELECTTitle FROMCourse WHERE (C_Num >= 200) AND (C_Num <= 299);

30 Use of Between List of Faculty’s name from D to E SELECTname FROMfaculty WHERE name BETWEEN ‘D’ AND ‘E’;

31 Use of IN IN: Tests against a list of values: (Set of values used for comparison) List of students with ID = 1111, ID = 2111 or ID = 3111 SELECTname FROMStudent WHERE ID IN (1111, 2111, 3111);

32 Use of IN SELECTname FROMStudent WHERE major IN (‘COSC’, ‘MATH’); SELECT name FROM Student WHERE major NOT IN (‘COSC’, ‘MATH’);

33 Example of IN page IN (2, 3,4, 5, 6) page NOT IN (2, 3,4, 5, 6) page BETWEEN 2 AND 6 section IN (‘A’, ‘B’, ‘C’, ‘D’, ‘E’) section NOT IN (‘A’, ‘B’, ‘C’, ‘D’, ‘E’) section BETWEEN ‘A’ AND ‘E’

34 Use of LIKE LIKE: Determines the presence of a sub string (_) a single unknown character (%) any number of unknown characters

35 Use of LIKE List all the student’s records so that the student’s name starts with a ‘K’ SELECT* FROMStudent WHERE name LIKE ‘K%’;

36 Use of LIKE List of students records with the second character to be ‘K’ SELECT* FROMStudent WHERE name LIKE ‘_K’;