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An expression is a combination of one or more values, operators and SQL functions that evaluate to a value. You can also use them to query the database for a specific set of data. Expressions can be used on forms with Query control and in scripting with $Database methods.
Remarks
Expressions can consist of multiple SQL functions. The following functions are available;
| Value | Description |
|---|---|
| Count | Count of row values. |
| CountDistinct | Count of distinct values in rows. |
| Sum | Sum of row values. Valid for numeric type columns. |
| SumDistinct | Sum of distinct values in rows. Valid for numeric type columns. |
| Avg | Average of row values. Valid for numeric type columns. |
| AvgDistinct | Average of distinct values in rows. Valid for numeric type columns. |
| Min | Minimum value in rows. |
| Max | Maximum value in row values. |
| StdDev | Standard deviation of row values. |
| DateDiff | Difference between two date values. Valid for date and datetime type columns. |
| DatePart | Crops out the specified part of date values and gives the kept part as number value. Valid for date and datetime type columns. |
| DateTrunc | Truncates date values except the specified date part and gives a date value. Valid for date and datetime type columns. |