Summarizing Data
The purpose of grouping data is to make the report easier to read by creating categories that the detail records fit into. Within these categories you perform various summary functions on fields so that the user can get an overview of the information within the group without having to read all the data. Crystal Reports has a large variety of summary functions to display for a group. Examples of these summary functions are sub-totals, averages, and maximum values. Table 4-1 shows a complete list of the summary functions available.
Table 4-1. Summary functions for groups.
| Function | Description |
|---|---|
| Average | Calculate the average value. (2) |
| Correlation | Calculate the correlation of two fields. (1) (2) |
| Count | Count the number of detail records. Fields with NULL values are not included in the calculation. (3) |
| Covariance | Calculate the measure of the linear relation between paired variables. (1) |
| DisctinctCount | Calculate the number of unique values for that field. |
| Maximimum | Find the maximum value of all the fields. |
| Median | Return the middle value if all the fields where sorted. (1) |
| Minimum | Find the minimum value of all the fields. |
| Mode | Returns the value with the most duplicates. |
| NthLargest | Finds the largest value of all the fields with a ranking of N. For example, if N were 6, it would return the sixth largest value. |
| NthMostFrequent | Finds the Nth ranking field with the most duplicate values. For example, if N were 6, it would return the value with the 6th most duplicates. |
| NthSmallest | Finds the smallest value of all the fields with a ranking of N. For example, if N were 6, it would return the sixth smallest value. |
| Percentage | Return a percentage of the grand-total for the selected field. (2) |
| Percentile | Returns the value for the specified percentile of the field. (2) |
| PopStandard | Deviation |
| Calculates how much a field deviates from the mean value. (1) (2) | SampleStanadard |
| Deviation | Return the sample standard deviation for the field. (1) (2) |
| SampleVariance | Return the sample variance for the field. (1) (2) |
| Sum | Return the total of all the detail fields.(2) |
| WeightedAverage | Return the weighted average of all the detail fields. (2) |
Chart Notes:
See a statistics book for more information.
Can only be used for numeric data.
NULL values can be included if you set them to return their default values. To do this, right-click on the report and select Report | Report Options. Then check the box for converting NULL field values to their default.
