Microsoft Access Tutorial B - Cengage Learning

MinVarStDevThe minimum of some field’s valuesThe variance of some field’s valuesThe standard deviation of some field’s valuesAT THE KEYBOARDSuppose that you want to know how many employees are represented in a database. The firststep is to bring the EMPLOYEE table into the QBE screen. Do that now. The query willCount the number of SSNs, which is a Sigma query operation. Thus, you must bring downthe SSN field.To tell Access you want a Sigma query, click the little “Sigma” icon in the menu, asshown in Figure B-19.Tutorial BFigure B-19Sigma iconThis opens up a new row in the lower part of the QBE screen, called the Total row. Atthis point, the screen would resemble that shown in Figure B-20.Figure B-20Sigma query set-upNote that the Total cell contains the words “Group By.” Until you specify a statisticaloperation, Access just assumes that a field will be used for grouping (stratifying) data.To count the number of SSNs, click next to Group By, revealing a little arrow. Click thearrow to reveal a drop-down menu, as shown in Figure B-21.Microsoft Access Tutorial 23