Background

A complete reference to every function available in the Elda Reporting Expression Editor. 

An expression is a small formula you type into the Report Designer's Expression Editor. The report evaluates it while the document is generated and uses the result.

What is an Expression?

Expressions are built from four ingredients: references to your data, literal values you type in, operators, and the functions.

 

Expression Groups

Frequently Used - Most reporting expressions come down to two things: naming a point in time, and moving a date backwards or forwards from it.

• Most reporting expressions come down to two things: naming a point in time, and moving a date backwards or forwards from it.

Aggregate Functions - Calculate a single value from a collection of related records.

• Aggregate functions run against a collection — typically a related detail table. You can filter the collection first by placing a condition in a second set of square brackets, then aggregate what remains.

Logical Functions - Branch on a condition, and deal with missing values.

• These are the workhorses of conditional formatting and conditional text. Iif chooses between values; the IsNull family keeps empty data from breaking a calculation or leaving a blank on the page.

Date & Time Functions - Test, build, shift and pull apart dates and times.

• This is the largest group in the expression language. It is easiest to navigate by what you are trying to do: test whether a date falls in a period, take a date apart, shift it, measure the gap between two dates, or build a new one from separate values.

Math Functions - Rounding, arithmetic, powers, logarithms and trigonometry.

String Functions - Combine, trim, search and reshape text.

Report-Specific Functions - Colours, parameter display text, and reading neighbouring rows.

• These functions exist only inside a report. They give an expression access to things that are not in the data source — the colour system, a parameter's display text, and the rows either side of the current one.

Summary Functions - Totals, counts and statistics across a group, a page or the whole report.

• These functions are offered by the Summary Expression Editor, which you open from a summary field rather than from an ordinary control. Each one is calculated across a summary region — a group, a page, or the report — which you choose separately from the expression itself. Functions beginning sumD count each distinct value once.

Expression Bindings & Calculated Fields - The extra functions available when you build a binding or a calculated field.

• The following functions are used to construct expression bindings and calculated fields.

Stored Procedure Functions - Passing multi-value parameters into a stored procedure.

• The following functions are used to bind a report to a stored procedure. Both deal with the same problem: a report parameter that holds several values, and a query parameter that expects one thing.