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In data processing, a pivot table is a data summarization tool found in data visualization programs such as spreadsheets or business intelligence software. Among other functions, a pivot table can automatically sort, count total or give the average of the data stored in one table or spreadsheet, displaying the results in a second table showing the summarized data. Pivot tables are also useful for quickly creating unweighted cross tabulations. The user sets up and changes the summary's structure by dragging and dropping fields graphically. This "rotation" or pivoting of the summary table gives the concept its name. The term ''pivot table'' is a generic phrase used by multiple vendors. In the United States, Microsoft Corporation has trademarked the specific compound word form, ''PivotTable''.〔(【引用サイトリンク】 title = United States Trademark Serial Number 74472929 ) 〕 Pivot tables can be seen as a simplification of the more complete and complex online analytical processing concepts (OLAP). ==History== In their book ''Pivot Table Data Crunching'',〔 〕 Bill Jelen and Mike Alexander refer to Pito Salas as the "father of pivot tables". While working on a concept for a new program that would eventually become Lotus Improv, Salas noted that spreadsheets have patterns of data. A tool that could help the user recognize these patterns would help to build advanced data models quickly. With Improv, users could define and store sets of categories, then change views by dragging category names with the mouse. This core functionality would provide the model for pivot tables. Lotus Development released Improv in 1991 on the NeXT platform. A few months after the release of Improv, Brio Technology published a standalone Macintosh implementation, called DataPivot (with technology eventually patented in 1999〔 〕). Borland purchased the DataPivot technology in 1992 and implemented it in their own spreadsheet application, Quattro Pro. In 1993 the Microsoft Windows version of Improv appeared. Early in 1994 Microsoft Excel 5 〔 〕 brought a new functionality called a "PivotTable" to market. Microsoft further improved this feature in later versions of Excel: * Excel 97 included a new and improved PivotTable Wizard, the ability to create calculated fields, and new pivot cache objects that allow developers to write Visual Basic for Applications macros to create and modify pivot tables * Excel 2000 introduced "Pivot Charts" to represent pivot-table data graphically In 2007 Oracle Corporation made PIVOT and UNPIVOT operators available in Oracle Database 11g.〔〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pivot table」の詳細全文を読む スポンサード リンク
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