Chapter 5Selected Single-Row

Functions

Chapter 5Selected Single-Row

Functions

TerminologyTerminology

Function – predefined block of code that accepts arguments– Single-row Function – returns one row of

results for each record processed– Multiple-row Function – returns one result

per group of data processed

Function – predefined block of code that accepts arguments– Single-row Function – returns one row of

results for each record processed– Multiple-row Function – returns one result

per group of data processed

Types of FunctionsTypes of Functions

Case Conversion FunctionsCase Conversion Functions

Alter the case of data stored in a column or character stringAlter the case of data stored in a column or character string

LOWER FunctionLOWER Function

Used to convert characters to lower-case lettersUsed to convert characters to lower-case letters

UPPER FunctionUPPER Function

Used to convert characters to upper-case lettersUsed to convert characters to upper-case letters

INITCAP FunctionINITCAP Function

Used to convert characters to mixed-caseUsed to convert characters to mixed-case

Character Manipulation FunctionsCharacter Manipulation Functions

Manipulates data by extracting substrings, counting number of characters, replacing strings, etc.

Manipulates data by extracting substrings, counting number of characters, replacing strings, etc.

SUBSTR FunctionSUBSTR Function

Used to return a substring, or portion of a stringUsed to return a substring, or portion of a string

LENGTH FunctionLENGTH Function

Used to determine the number of characters in a stringUsed to determine the number of characters in a string

LTRIM and RTRIM FunctionsLTRIM and RTRIM Functions

Used to remove a specific string of charactersUsed to remove a specific string of characters

REPLACE FunctionREPLACE Function

Substitutes a string with another specified stringSubstitutes a string with another specified string

CONCAT FunctionCONCAT Function

Used to concatenate two character stringsUsed to concatenate two character strings

ROUND FunctionROUND Function

Used to round numeric columns to a stated precision

Used to round numeric columns to a stated precision

MONTHS_BETWEEN FunctionMONTHS_BETWEEN Function

Determines the number of months between two datesDetermines the number of months between two dates

ADD_MONTHS FunctionADD_MONTHS Function

Adds a specified number of months to a dateAdds a specified number of months to a date

NEXT_DAY FunctionNEXT_DAY Function

Determines the next occurrence of a specified day of the week after a given date

Determines the next occurrence of a specified day of the week after a given date

DECODE FunctionDECODE Function

Determines action based upon values in a listDetermines action based upon values in a list

Nesting FunctionsNesting Functions

One function is used as an argument inside another function

Must include all arguments for each function Inner function is resolved first, then outer

function

One function is used as an argument inside another function

Must include all arguments for each function Inner function is resolved first, then outer

function