1. Database Programming Sections 1 & 2 – Case and Character Manipulations, number functions, date functions, conversion functions, general functions, conditional expressions, Null functions

2. Marge Hohly2 DUAL function  The DUAL table has one row called "X" and one column called "DUMMY.“  The DUAL table is used to create SELECT statements and execute commands not directly related to a specific database table.

3. Marge Hohly3 Single Row Functions  Single row functions are very powerful pre- defined code that accepts arguments and returns a value. An argument can be defined as a column name, an expression, or a constant.  There are five single row functions groups: Character Date General Number Conversion

4. Case/Character Manipulation Marge Hohly4

5. 5 Single Row Functions  Single-row character functions are divided into two categories: functions that convert the case of character strings functions that can join, extract, show, find, pad, and trim character strings.  Single-row functions can be used in the SELECT, WHERE, and ORDER BY clauses.

6. Marge Hohly6 Single Row Functions  Character Functions (Case manipulation) LOWER converts character strings to all lower case. SELECT last_name FROM employees WHERE last_name = ‘king’ WHERE LOWER(last_name) = ‘king’ (should be this way) UPPER converts character strings to all upper case. INITCAP converts the first letter of each word to upper case and the remaining letters to lower case.

7. Case Manipulation  LOWER(column|expression) converts alpha characters to lower-case.  UPPER(column|expression) converts alpha character to upper case  INITCAP(column|expression) converts alpha character values to uppercase for the first letter of each word. (Title Case) Marge Hohly7

8. 8 Character Functions  Character Functions (Case manipulation) FunctionResult LOWER (‘I Love SQL’)i love sql UPPER (‘I love SQL’)I LOVE SQL INITCAP(‘I Love SQL’)I Love Sql

9. Marge Hohly9 DUAL examples  SELECT LOWER('Marge') FROM dual;  SELECT UPPER(‘Hello’) FROM dual;  SELECT SYSDATE FROM dual;

10. Marge Hohly10 LOWER examples  Create a query that outputs the CD titles in the DJ on Demand database in all lowercase letters. SELECT LOWER(title) FROM d_cds;  Create a query that selects the first names of the DJ on Demand clients who have an "a" somewhere in their name. Output the results set in all uppercase letters. Ask students why UPPER was put in the SELECT statement and not in the WHERE clause. SELECT UPPER(first_name) FROM d_clients WHERE first_name LIKE '%a%';

11. Marge Hohly11 Using LOWER, UPPER & INITCAP  Use LOWER, UPPER, & INITCAP in SELECT statement to affect the output of the data  Use in WHERE & ORDER BY to determine how data is chosen not displayed  SELECT last_name,job_id FROM employees WHERE LOWER(job_id) = ‘it_prog‘;  SELECT UPPER(last_name),job_id FROM employees;

12. Marge Hohly12 Character Functions  Character Functions (Character manipulation) CONCAT joins two values together. SUBSTR extracts a string of characters from a value. LENGTH shows the length of a string as a numeric value. LPAD/RPAD pads specified character to the left or right. TRIM trims leading, trailing, or both characters from a string. REPLACE replaces a string of characters.

13. Marge Hohly13 Single Row Functions  Character Functions (Character manipulation) FunctionResult CONCAT(‘ABC’, ‘DEF’)ABCDEF SUBSTR(‘ABCDEF’,2,3)BCD LENGTH(‘ABCDEF’)6 INSTR(‘ABCDEF’,’C’)3

14. Marge Hohly14 Try these  SELECT SUBSTR(hire_date, 2, 4) FROM employees;  SELECT LENGTH(last_name), last_name FROM employees;  SELECT LPAD(‘123-56-8901’,15,’*’) FROM dual;

15. Marge Hohly15 Single Row Functions  Character Functions (Character manipulation) FunctionResult LPAD (salary,9,’*’)****15000 RPAD (salary,9,’*’)15000**** TRIM (leading ‘A’ from ‘ABCA’) trailing or both BC REPLACE(‘ABC’,’B’,’*’)A*C

16. Marge Hohly16 Try These  SELECT LPAD(salary, 9, '*') FROM employees;  SELECT TRIM(trailing 'a’ from 'abbba') FROM dual;  SELECT TRIM(both 'a’ from 'abbba') FROM dual;  SELECT REPLACE('ABC', 'B','*') FROM dual;

17. Terminology Review  DUAL- Dummy table used to view results from functions and calculations  Format-The arrangement of data for storage or display.  INITCAP-Converts alpha character values to uppercase for the first letter of each word, all other letters in lowercase. Marge Hohly17

18. Terminology cont.  Character functions-Functions that accept character data as input and can return both character and numeric values.  TRIM-Removes all specified characters from either the beginning or the ending of a string.  Expression -A symbol that represents a quantity or a relationship between quantities Marge Hohly18

19. Terminology cont.  Single- row functions-Functions that operate on single rows only and return one result per row  UPPER-Converts alpha characters to upper case  Input-Raw data entered into the computer  CONCAT-Concatenates the first character value to the second character value; equivalent to concatenation operator (||). Marge Hohly19

20. Terminology cont.  Output-Data that is processed into information  LOWER-Converts alpha character values to lowercase.  LPAD-Pads the left side of a character, resulting in a right-justified value  SUBSTR-Returns specific characters from character value starting at a specific character position and going specified character positions long Marge Hohly20

21. Use Alias in Functions  Aliases can be used in commands to replace column name etc.  SELECT LOWER(SUBSTR(first_name,1,1)) ||LOWER(last_name) AS “User Name” FROM f_staffs; Marge Hohly21

22. Terminology cont.  REPLACE-Replaces a sequence of characters in a string with another set of characters.  INSTR-Returns the numeric position of a named string.  LENGTH-Returns the number of characters in the expression  RPAD-Pads the right-hand side of a character, resulting in a left- justified value. Marge Hohly22

23. Marge Hohly23 Single Row Functions  Number Functions ROUND rounds a value to specified position. TRUNC truncates a value to a specified position. MOD returns the remainder of a divide operation.

24. Single Row Functions  Number Functions ROUND rounds a value to specified position. ROUND(column|expression, decimal places) Default is 0 decimals  SELECT ROUND(45.927, 2), ROUND(45.927, 0), ROUND(45.927), ROUND(45.927, -1) FROM dual; Marge Hohly24

25. Single Row Functions  TRUNC truncates a value to a specified position. TRUNC(column|expression, decimal places) SELECT TRUNC(45.927, 2),TRUNC(45.927, 0),TRUNC(45.927),TRUNC(45.927, -1) FROM dual; TRUNC(45.927, 2) = 45.92 TRUNC(45.927, 0) = 45 TRUNC(45.927) = 45 TRUNC(45.927, -1) = 40 Marge Hohly25

26. Mod demo  MOD returns the remainder of a divide operation.  MOD(1 st value, 2 nd value) The 1 st value is divided by the 2 nd value SELECT MOD(600, 500) FROM dual;  SELECT last_name, salary, MOD(salary, 2) AS “Mod Demo” FROM f_staffs WHERE staff_type IN(‘Order Taker’, ‘Cook’, ‘Manager’); Marge Hohly26

27. Marge Hohly27 Single Row Functions  Working with Dates the default display and input format for any date is DD-MON-RR. For example: 12-OCT-05 (more on RR later) SYSDATE is a date function that returns the current database server date and time. the Oracle database stores dates in an internal numeric format. Which means arithmetic operations can be performed on dates. default date DD-MON-RR. Oracle dates are between 1/1/4712 B.C. and 12/31/9999 A.D. Stores year as a 4 digit value, 2 digit century, 2 digit year

28. Date Functions Example Marge Hohly28

29. Marge Hohly29 Examples  SELECT SYSDATE FROM DUAL;  SELECT (SYSDATE - hire_date)/7 AS "No. of Weeks“ FROM employees;  SELECT MONTHS_BETWEEN(SYSDATE, '01- Jan-87') AS "no. of months“ FROM dual;  SELECT ROUND(MONTHS_BETWEEN(SYSDATE, '01-Jan-87'),2) AS "no. of months“ FROM dual;  SELECT NEXT_DAY('01-Sep-95','Friday') FROM dual;

30. Marge Hohly30 Date Functions FunctionsDescription months_between# of months between 2 dates add_monthsAdd calendar months to date next_dayNext day of the date specified (like Friday) last_dateLast day of month (date) ROUNDRound date TRUNCTruncate date

31. Marge Hohly31 Single Row Functions  Working with Dates (a few examples) SELECT last_name, hire_date + 60 AS "Review Date“ FROM employees; SELECT last_name, (SYSDATE-hire_date)/7 FROM employees; SELECT order_no,amt_due,purch_date + 30 AS "Due Date“ FROM transactions;

32. Marge Hohly32 Single Row Functions  Date Functions MONTHS_BETWEEN returns the number of months between two dates. ADD_MONTHS adds a number of months to a date. NEXT_DAY returns the date of the next specified day of the week. LAST_DAY returns the date of the last day of the specified month. ROUND returns the date rounded to the unit specified. TRUNC returns the date truncated to the unit specified.

33. Marge Hohly33 Single Row Functions  Date Functions (a few examples) FunctionsResult MONTHS_BETWEEN(’01- SEP-92’,’01-JUN-91’) 15 ADD_MONTHS (’11-JAN- 94’,6) ’11-JUL-94’ NEXT_DAY(’01-SEP- 95’,’FRIDAY’) ‘08-SEP-95’ LAST_DAY(’01-FEB-95’)’28-FEB-95’

34. Marge Hohly34 Single Row Functions  Date Functions (a few more examples) Assume SYSDATE = ’25-JUL-95’ FunctionResult ROUND(SYSDATE,’MONTH’)’01-AUG-95’ ROUND(SYSDATE,’YEAR’)’01-JAN-96’ TRUNC(SYSDATE,’MONTH’)’01-JUL-95’ TRUNC(SYSDATE,’YEAR’)’01-JAN-95’

35. Marge Hohly35 Date Types Data Type conversion Implicit data type conversion Explicit data type conversion

36. Data Types  VARCHAR2: Used for character data of variable length, including numbers, special characters, and dashes.  CHAR: Used for text and character data of fixed length, including numbers, dashes, and special characters.  NUMBER: Used to store variable-length numeric data. No dashes, text, or other nonnumeric data are allowed. Currency is stored as a number data type.  DATE: Used for date and time values. Internally, Oracle stores dates as numbers and by default DATE information is displayed as DD-MON-YY (for example, 16-OCT-07). Marge Hohly36

37. Marge Hohly37 Implicit Data Type Conversion  For assignments, the Oracle serve can automatically convert the following: FromTo VARCHAR2 or CHARNUMBER VARCHAR2 or CHARDATE NUMBERVARCHAR2 DATEVARCHAR2

38. Marge Hohly38 Explicit Type Conversion TO_NUMBER TO_DATE CHARACTERNUMBERDATE TO_CHAR

39. Marge Hohly39 Using the TO_CHAR Function with Dates  The format model: TO_CHAR(date column name, ‘format model you specify’) Must be enclosed in single quotation marks and is case sensitive Can include any valid date format element Has an fm element to remove padded blanks or suppress leading zeros Is separated from the date value by a comma

40. Using the TO_CHAR Function with Dates  Use sp to spell out a number  Use th to have the number appear as an ordinal  Use double quotation marks to add character strings to format models Marge Hohly40

41. Marge Hohly41 Elements of the Date Format Model  YYYY  YEAR  MM  MONTH  MON  DY  DAY  DD  Full year in numbers  Year spelled out  Two-digit value for month  Full name of the month  Three-letter abbreviation of the month  Three-letter abbreviation of the day of the week  Full name of the day of the week  Numeric day of the month

42. Marge Hohly42 Examples of Date formatting  Date conversion to character data June 19th, 2004 TO_CHAR(hire_date, 'Month ddth, YYYY') January 1, 2000 TO_CHAR(hire_date, 'fmMonth dd, YYYY') MAR 5, 2001 TO_CHAR(hire_date, 'fmMON dd, YYYY') June 17th Wednesday Nineteen Eighty- Seven TO_CHAR(hire_date, 'Month ddth Day YYYYSP')

43. Marge Hohly43 Examples  Using the current SYSDATE display it in the following format August 6th, 2004 August 06, 2004 AUG 6, 2004 August 6th, Friday, Two Thousand Four

44. Marge Hohly44 Using Date Format  SELECT employee_id, TO_CHAR(hire_date,'MM/YY') Month_Hired FROM employees WHERE last_name = 'Higgins'; EMPLOYEE_IDMONTH_HIRED 20506/94

45. Marge Hohly45 Elements of the Date Format Model  Time elements format the time portion of the date.  Add character strings by enclosing them in double quotation marks.  Number suffixes spell out numbers. HH24:MI:SS AM15:45:32 PM Ddspthfourteenth DD “of” MONTH12 of OCTOBER

46. Marge Hohly46 Using the TO_CHAR Function with Dates SELECT last_name, TO_CHAR(hire_date, 'fmDD Month YYYY') AS HIREDATE FROM employees; LAST_NAMEHIREDATE King17 June 1987 Kochhar21 September 1989 De Haan13 January 1993 Whalen17 September 1987 Higgins7 June 1994 Gietz7 June 1994

47. Marge Hohly47 Using the TO_CHAR Function with Numbers  TO_CHAR (number, ‘format_model’) These are some of the format elements you can use with the TO_CHAR function to display a number value as a character: 9Represents a number 0Forces a zero to be displayed $Places a floating dollar sign LUses the floating local currency symbol.Prints a decimal point,Prints a thousand indicator BDisplay zero values as blanks not 0

48. Marge Hohly48 Number conversions to Character (VARCHAR2)  Can you identify the format models used to produce the following output? $3000.00 4,500 9,000.00 0004422

49. Marge Hohly49 Using the TO_CHAR Function with Numbers  SELECT TO_CHAR(salary, '$99,999.00') SALARY FROM employees WHERE last_name = 'Ernst‘; SALARY $6,000.00

50. Marge Hohly50 Using the TO_NUMBER and TO_DATE Functions  Convert a character string to a number format using the TO_NUMBER function: TO_NUMBER(char[, ‘format_model’])  Convert a character string to a date format using the TO_DATE function: TO_DATE(char[, ‘format_model’])  These functions have a fx modifier. This modifier specifies the exact matching for the character argument and date format model of a TO_DATE function

51. Marge Hohly51 Using fx modifier  Use the fx modifier to format dates exactly as follows June19 2004 July312004  Format your birth date use DUAL Example June 19, 1990

52. Marge Hohly52 RR Date Format-dates over 2 centuries Current DateSpecified DateRR FormatYY Format 199527-OCT-951995 27-OCT-1720171917 200827-OCT-172017 200827-OCT-9519952095 If the specified two-digit year is: 0-4950-99 If two digits of the current year are: 0-49 The return date is in the current century The return date is in the century before the current one 50-99 The return date is in the century after the current one The return date is in the current century

53. Marge Hohly53 Example of RR Date Format  To find employees hired prior to 1990, use the RR format, which produces the same results whether the commands is run in 1999 or now:  SELECT last_name, TO_CHAR(hire_date, 'DD-Mon-YYYY') FROM employees WHERE hire_date < TO_DATE('01-Jan-90', 'DD-Mon-RR'); LAST_NAMETO_CHAR(HIRE_DATE,'DD-MON-YYYY') King17-Jun-87 Kochhar21-Sep-89 Whalen17-Sep-87

54. Marge Hohly54 Try this  SELECT last_name, hire_date, TO_CHAR(hire_date, 'DD-Mon-RRRR') FROM employees WHERE TO_DATE(hire_date, 'dd- mon-RR') < '01 Jan 1999‘

55. Marge Hohly55 YY and RR  SELECT TO_CHAR(TO_DATE(hire_date, 'DD- Mon-RR'),'DD Mon YYYY') AS "RR Example“ FROM employees;  SELECT TO_CHAR(TO_DATE(hire_date, 'DD-Mon- YY'),'DD Mon YYYY') AS "YY Example“ FROM employees YY Example 17 Jun 2087 21 Sep 2089 13 Jan 2093 RR Example 17 Jun 1987 21 Sep 1989 13 Jan 1993

56. Marge Hohly56 Examples 2. Convert January 3, 2004, to the default date format 03-JAN-04. 4. Convert today's date to a format such as: "Today is the Twentieth of March, Two Thousand Four“ 8. Create one query that will convert 25-DEC-04 into each of the following (you will have to convert 25- DEC-04 to a date and then to character data): December 25th, 2004 DECEMBER 25TH, 2004 december 25th, 2004

57. Marge Hohly57 Nested Functions  Nesting is allowed to any depth  Evaluate from the inside out

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59. Marge Hohly59 Null Functions  Null is unavailiable, unassigned, unknown, or inapplicable. NVL NVL2 NULLIF COALESCE

60. Marge Hohly60 NVL FUNCTION  NVL function converts a null value to a date, a character, or a number.  The data types of the null value column and the new value must be the same.  NVL (value that may contain a null, value to replace the null)  can be used to convert column values containing nulls to a number before doing calculations.  When arithmetic calculation is performed with null, the result is null.

61. Marge Hohly61 NVL FUNCTION examples  SELECT NVL(auth_expense_amt,0) FROM d_partners;  SELECT NVL(hire_date,'01-JAN-97') FROM employees;  SELECT NVL(specialty,'None Yet') FROM d_partners;  SELECT first_name, last_name,NVL(auth_expense_amt, 0) * 1.05 AS Expenses FROM D_Partners;

62. Marge Hohly62 NVL2 FUNCTION  NVL2 (expression 1 value that may contain a null, expression 2 value to return if expression 1 is not null, expression 3 value to replace if expression 1 is null)  SELECT last_name, salary, NVL2(commission_pct, salary + (salary * commission_pct), salary) income FROM employees;

63. Marge Hohly63 NULLIF FUNCTION  NULLIF function compares two functions.  If they are equal, the function returns null.  If they are not equal, the function returns the first expression.  The NULLIF function is: NULLIF(expression 1, expression 2)  SELECT first_name, LENGTH(first_name) "Expression 1",last_name, LENGTH(last_name) "Expression 2", NULLIF(LENGTH(first_name), LENGTH(last_name)) AS "Compare Them“ FROM D_PARTNERS;

64. Marge Hohly64 COALESCE FUNCTION  The COALESCE function is an extension of the NVL function, except COALESCE can take multiple values.  If the first expression is null, the function continues down the line until a not null expression is found.  If the first expression has a value, the function returns the first expression and the function stops.

65. Marge Hohly65 Examples Section 2 Lesson 2 2.Not all Global Fast Foods staff members receive overtime pay. Instead of displaying a null value for these employees, replace null with zero. Include the employee's last name and overtime rate in the output. Label the overtime rate as "Overtime Status." 4.Not all Global Fast Foods staff members have a manager. Create a query that displays the employee last name and 9999 in the manager ID column for these employees.

66. Marge Hohly66 Conditional Expressions  Provide the use of IF-THEN-ELSE logic within a SQL statement  Use two methods: CASE expressions DECODE function

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68. Marge Hohly68 CASE Function – when – then - else  Facilitates conditional inquiries by doing the work of an IF-THEN-ELSE statement: SELECT last_name, job_id, salary, CASE job_id WHEN 'IT_PROG' THEN 1.10*salary WHEN 'ST_CLERK' THEN 1.15*salary WHEN 'SA_REP' THEN 1.20*salary ELSE salary END "REVISED_SALARY“ FROM employees;

69. Marge Hohly69 DECODE Function  Facilitates conditional inquires by doing the work of a CASE or IF_THEN_ELSE statement: SELECT last_name, job_id, salary, DECODE(job_id, 'IT_PROG',1.10*salary, 'ST_CLERK',1.15*salary, 'SA_REP',1.20*salary, salary) "REVISED_SALARY“ FROM employees;

70. Marge Hohly70 DECODE Example SELECT last_name, salary, DECODE (TRUNC(salary/2000, 0), 0,0.00, 1,0.09, 2,0.20, 3,0.30, 4,0.40, 5,0.42, 6,0.44, 0.45) TAX_RATE FROM employees WHERE department_id = 80; Monthly Salary Range Rate $0.00 – 1999.99 00% $2,000.00 – 3,999.99 09% $4,000.00 – 5,999.99 20% $6,000.00 – 7,999.99 30% $8,000.00 – 9,999.99 40% $10,000.00 – 11,999.99 42% $12,200.00 – 13,999.99 44% $14,000.00 or greater 45%

71. Marge Hohly71 Practice 1. For each Global Fast Foods promotional menu, display the event name, and calculate the number of months between today and the ending date of the promotion. Round the months to a whole number. Label the column "Past Promos." 2. Use the Oracle database to write a query that returns the salary for employee 174 as: Ellen Abel earns $11000.00 monthly but wants $14000.00