Monday, September 21, 2009

Single-Row Functions

Single-row functions:
  • Manipulate data items
  • Accept arguments and return one value
  • Act on each row that is returned
  • Return one result per row
  • May modify the data type
  • Can be nested
  • Accept arguments that can be a column or an expression

Sunday, September 20, 2009

SQL functions

Functions are a very powerful feature of SQL

They can be used to do the following:
  • Calculations on data
  • Modify individual data items
  • Manipulate output for groups of rows
  • Format dates and numbers for display
  • Convert column data types
  • SQL functions sometimes take arguments and always return a value
Two Types of SQL Functions :



  • Single-Row Functions
    – These functions operate on single rows only and return one result per row. There are different types of single-row functions.
  • future posts covers the following ones:
    • Character
    • Number
    • Date
    • Conversion
    • General
  • Multiple-Row Functions
    – Functions can manipulate groups of rows to give one result per group of rows. These functions are also known as group functions

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