# Chapter Six Data Manipulation Language (DML) Functions Objectives Single Row functions Character functions Number functions Date functions.

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Chapter Six Data Manipulation Language (DML) Functions Objectives Single Row functions Character functions Number functions Date functions

2 Functions Introduction Types of functions Single row Multiple rows

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: SMITHLori

7 Character Manipulation CONCAT (Col 1 | Exp 1, Col 2 | Exp 2 ) 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: SELECTLOWER(name), UPPER(major), LENGTH(name) FROMstudent; SELECT CONCAT(Name, Address), GPA FROMStudent; SELECT Name || ‘--->‘ || Address, GPA FROMStudent;

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): SELECTName FROMStudent WHERELENGTH(Address)<20; SELECTName, SUBSTR (SSN, 5,2) FROMStudent; SELECTName, SUBSTR (SSN,5) FROMStudent;

15 List(Characters): SELECTRPAD (INITCAP(LOWER(Name)),70,’.’), SUBSTR (SSN,5) FROM Student ; SELECTName FROMStudent WHERESUBSTR (SSN,5,2)=’80’; SELECTName, SUBSTR (SSN,-4) FROMStudent;

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

17 List(Characters): SELECTName, INSTR (Name,’r’) FROMStudent; ------------------------------------------------ MARY3 JOHN0 ROBIN1 SELECT Name, INSTR (Name,’r’,1,2) FROMStudent; SELECTName, INSTR(Address,’Frostburg’) FROMStudent;

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) SELECTROUND(Salary,1) FROMFaculty; SELECTTRUNC(234.111,2), FROMDUAL; 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 SELECTname, SYSDATE - B_Date FROMstudent;

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 FROMStudent;

27 DATE: ROUND(date [,fmt]) SELECT name, ROUND (B_Date,’MONTH’) FROMStudent; SELECT name, ROUND(B_Date,’YEAR’) FROMStudent;

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) FROMStudent;

32 Conversion Function: SELECTSUBSTR(ssn,1,3) || ‘-’ || SUBSTR(ssn,4,2) || ‘-’ || SUBSTR(ssn,6) FROMStudent;

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