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Chapter Six Data Manipulation Language (DML) Functions

Chapter Six Data Manipulation Language (DML) Functions. Objectives Single Row functions Character functions Number functions Date functions. Functions. Introduction Types of functions Single row Multiple rows. Single Row Functions:. FACTS: Act on each row

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Chapter Six Data Manipulation Language (DML) Functions

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  1. Chapter SixData Manipulation Language (DML)Functions Objectives Single Row functions Character functions Number functions Date functions

  2. Functions • Introduction • Types of functions • Single row • Multiple rows

  3. Single Row Functions: FACTS: Act on each row Return one result per row May modify the data type returned type Can be nested

  4. Single Row Functions • Character • Number • Date • Conversion • General

  5. Character Manipulation: • LOWER(Col | Exp) LOWER(‘Database course’) • UPPER (Col | Exp) UPPER (‘Database course’) • INITCAP (Col | Exp) INITCAP (‘Database course’)

  6. Practice: • Display last name and first name of customers. Last name in upper case. First character of each first name in upper case, the rest in lower case. • Example: SMITH Lori

  7. Character Manipulation • CONCAT (Col1 | Exp1, Col2 | Exp2) CONCAT(‘This ‘,’that’) • SUBSTR(Col | Exp,n,[m]) SUBSTR(‘This is it’,2,5) • LPAD(Col | Exp,n,’string’) LPAD(name,9,’.’)

  8. Character Manipulation • LENGTH(Col | Exp) LENGTH(‘this is it’) • CHR(integer) CHR(97) • INSTR(‘Computer’,’m’)

  9. List(Characters): • Example: • SELECT LOWER(name), UPPER(major), LENGTH(name) FROM student; • SELECT CONCAT(Name , Address) , GPA FROM Student; • SELECT Name || ‘--->‘ || Address , GPA FROM Student;

  10. List(Characters): • SELECTRPAD (Name, 40, ‘.’), GPA FROM Student; JOHN............... 3.1 MARY ............. 3.2 • SELECTRPAD (Name, 20), GPA FROM Student; MARY 3.2 MOHAMMAD 3.3 • SELECTLPAD (Name, 20), GPA FROM Student; MARY 3.2 MOHAMMAD 3.3

  11. Practice: • Display the last name and address of each customer together. In the next column display customer phone number. • SMITH 11 MAIN ST FROSTBURG MD……..301 689 1111

  12. List(Characters): • RTRIM(Col) RTRIM (Name) RTRIM (Name, ‘.’) LTRIM (Name, ‘ABC’) LTRIM ( RTRIM( Name, ‘.’ ), ‘a’) From Student;

  13. Practice: • Customer phone number is stored as: -301-689-1111: Part 1- We would like to delete the first dash and the last colon from the phone numbers: -301-689-1111: Part 2- Remove all dashes and colon

  14. List(Characters): • SELECT Name FROM Student WHERE LENGTH(Address)<20; • SELECT Name, SUBSTR (SSN, 5 ,2) FROM Student; • SELECT Name, SUBSTR (SSN,5) FROM Student;

  15. List(Characters): • SELECT RPAD (INITCAP(LOWER(Name)),70,’.’), SUBSTR (SSN,5) FROM Student; • SELECT Name FROM Student WHERE SUBSTR (SSN,5,2)=’80’; • SELECT Name, SUBSTR (SSN,-4) FROM Student;

  16. Practice: • Display the 10 characters from OrderPart description starting at location 6. • Example: Door Replacement Handle

  17. List(Characters): • SELECT Name, INSTR (Name,’r’) FROM Student;   ------------------------------------------------ MARY 3 JOHN 0 ROBIN 1 • SELECT Name, INSTR (Name,’r’,1,2) FROM Student; • SELECT Name, INSTR(Address,’Frostburg’) FROM Student;

  18. Practice: • We would like to switch the position of last name with the first name. Assume the attribute name consists of both first and last names with a blank character in between.

  19. LIST(Numbers) • ROUND (value, precision) ROUND(234.1161,2) • TRUNC(value, precision) TRUNC(234.1161,2) • POWER(value,exponent) POWER(3,2)  • MOD(value1, value2) MOD(900,400)

  20. LIST(Numbers) • SELECT ROUND(Salary,1) FROM Faculty; • SELECT TRUNC(234.111,2), FROM DUAL; TRUNC(234.567); TRUNC(234.5678,-2);

  21. DATE: • Date is stored in an internal numeric format: century, year, month, day, hours, minutes, second • Default date is DD-MON-YY • SYSDATE

  22. DATE: • Example: List the ages of students • SELECT name, SYSDATE - B_Date FROM student;

  23. Practice: • Display today’s date.

  24. Date • Date + number • Date – number • Date – date • Date + number/24

  25. DATE: • MONTHS_BETWEEN(day1,day2) • SELECT name, MONTHS_BETWEEN(SYSDATE , B_Date) age_in_month FROM Student;

  26. DATE: • ADD_MONTHS (date,n) SELECT name, ADD_MONTHS(B_Date,5) age FROM Student;

  27. DATE: • ROUND(date [,fmt]) • SELECT name, ROUND (B_Date,’MONTH’) FROM Student; • SELECT name, ROUND(B_Date,’YEAR’) FROM Student;

  28. Conversion Function: Implicit conversion (Automatic): • CHAR or VARCHAR2 to NUMBER • CHAR or VARCHAR2 to DATE • NUMBER to VARCHAR2 • DATE to VARCHAR2

  29. Conversion Function: Explicit datatype conversion: • TO_CHAR (NUMBER [,‘fmt’] ) • TO_CHAR (DATE [,‘fmt’] ) • TO_DATE (CHAR [,‘fmt’] ) • TO_NUMBER (CHAR [,‘fmt’] )

  30. Conversion Function: SELECT TO_CHAR(b_date,’MM/YY’) FROM student; Format: • YYYY • YEAR • MM • MONTH • DY • DAY

  31. Conversion Function: • SELECT SUBSTR(TO_CHAR(111223333),1,3) ||‘-’ || SUBSTR (TO_CHAR(111223333),4,2) || ‘-’ || SUBSTR(TO_CHAR(111223333),6) FROM Student;

  32. Conversion Function: • SELECT SUBSTR(ssn,1,3) || ‘-’ || SUBSTR(ssn,4,2) || ‘-’ || SUBSTR(ssn,6) FROM Student;

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