Prior to the introduction of AutoCAD, most commercial CAD programs ran on mainframe computers or minicomputers, with each CAD operator (user) working at a separate graphics terminal. AutoCAD is used across a wide range of industries, by architects, project managers, engineers, graphic designers, and other professionals. It is supported by 750 training centers worldwide as of 1994.
Aggregate Functions (Transact-SQL) Aggregate functions perform a calculation on a set of values and return a single value. Except for COUNT, aggregate functions ignore null values. Aggregate functions are frequently used with the GROUP BY clause of the SELECT statement. All aggregate functions are deterministic.
returns the total number of values in a given column. COUNT(*) returns the number of rows in a table. Aggregate functions are used to compute against a returned column of numeric data from your SELECT statement. They basically summarize the results of a particular column of selected data. We are covering these here since they are required by the next topic, GROUP BY.