27 Formulas and Variables

Transcription

1 27 Formulas and Variables Formulas and variables enable you to add custom calculations within reports. One advantage of variables is they are given a name and are re-usable across the whole document, whereas formulas need to be copied and pasted if you need to use them in multiple places. Another advantage of variables is that if you make the change to the variable definition then the new definition will automatically be applied across the whole document, whereas with formulas you would need to modify each occurrence individually. This session introduces custom calculations using functions and variables Viewing Formulas The Formula Bar is located immediately above the report canvas area: View and Edit formulas in this text box. Formula Bar Buttons: To initiate the Formula Editor To take the current formula and Create Variable from the formula definition Formula Bar can be activated from the Properties Toolbar. To Cancel the formula To Validate the formula Formulas may be entered directly into the formula text box on the Formula Bar, but for long and/or complicated formulas, proper syntax can be best achieved using the Formula Editor. Select a cell (within a block or free standing) and the Formula Bar will display the formula associated to the selected cell. 441

2 IMPORTANT POINTS ON FORMULAS AND VARIABLES: 1. Formulas and variables always begin with an = sign, e.g. =[Year]. 2. Following the = sign, you may use objects, other variables, functions or appropriate operators in the syntax of your formula. 3. All object and variable names should be enclosed within square brackets, e.g. [Year] Creating Formulas using the Formula Bar We will now take a look at how to create formulas using the Formula Bar. 1. Create the following query using the efashion universe and run it. Create the vertical table shown opposite using a break on [Year]. 442

3 2. We would like to add in an extra column to the right of [Margin] to show [Margin] as a percentage of [Sales revenue]. To add in an extra column click in any cell of the [Margin] column and then use right-click menu Insert Insert column on right. 3. After adding the new column, make sure the Formula Bar is showing. Click in any body cell of the column and then click in the text box of the Formula Bar. The formula we require to calculate [Margin] as a percentage of [Sales revenue] is: 1. The formula starts with an = sign 2. Both object names are enclosed in square brackets, e.g. [Margin] 3. Spaces (and parentheses) can be used to break formulas up for readability, e.g. =[Margin]/[Sales revenue] or we can use spaces = [Margin] / [Sales revenue] 443

4 4. Click on Validate or press <Enter> and Web Intelligence will perform the calculation if there are no errors. If there is an error then a message will be displayed indicating where the possible error is within the formula. Web Intelligence has performed the calculation [Margin] / [Sales revenue] in the right hand column. 5. Change the Number Format of the body cells in the last column to show the cell contents as percentages. 6. Click in the column header cell and then type in the formula: Margin % Validate the formula and this will become the label for the column header. NOTE For literal text/labels you can use following syntax: Or simply = Margin % Margin % 444

5 27.3 Creating Formulas using the Formula Editor We will recreate the previous formula using the Formula Editor to show its ease of use. 1. Delete the formula we have previously created in the body cell of the Margin % column. Simply select the formula, press the <Del> key (or the <Delete> key), then press <Enter> or click on Validate. 2. With a body cell selected in the Margin % column, click on the Formula Editor button that is within the Formula Bar. This will activate the Formula Editor. Formula definitions are created here. Available objects for including in formulas. When an object is selected from the Available objects pane, or a Function from the Functions pane, or an Operator from the Operators pane then an associated Description is displayed here. 445