Dynamic Filtering Patterns in OutSystems Aggregates

Open your Aggregate → click the Filters tab (second tab, after Sources). Click 'Add filter' (the + icon). The Expression editor opens. For a static filter — always filtering to active employees: `Employee.IsActive = True` Click OK. The filter appears in the Filters list with a checkbox (enabled by default). For a static date filter: `Employee.HireDate >= #2020-01-01#` Date literals in OutSystems use #yyyy-MM-dd# format. DateTime literals: #2020-01-01 00:00:00#. Multiple filters in the list are AND'd: the query returns rows matching ALL conditions simultaneously.

Dynamic filters read their values from screen variables at runtime. In Service Studio, open your screen → right-click the screen name in the Interface tab → Add Local Variable. Name it 'SearchName' with Data Type = Text, Default Value = "". Add more variables as needed: - 'FilterDepartmentId' (Department Identifier, Default = NullIdentifier()) - 'FilterIsActive' (Boolean, Default = True) - 'FilterHireDateFrom' (Date, Default = NullDate()) - 'FilterHireDateTo' (Date, Default = NullDate()) These variables are what your Input widgets will bind to, and what your Aggregate filters will read from.

In the Aggregate's Filters tab, click Add filter. Write this expression: `SearchName = "" or Index(ToLower(Employee.FirstName + " " + Employee.LastName), ToLower(SearchName), 0) >= 0` This is the optional filter pattern: - When SearchName = "" (empty): the first condition is true, so ALL rows pass through - When SearchName has a value: Index() searches for the string within the full name (case-insensitive) The Index() function returns the position of the search string (-1 if not found, >= 0 if found). Alternative using Contains-style pattern: `SearchName = "" or Employee.LastName like "%" + SearchName + "%"` Note: the 'like' operator is available in OutSystems expressions for Aggregate filters. Index() is preferred for case-insensitive search.

1/* Dynamic text search — optional filter pattern */
2
3/* Search by full name (case-insensitive) */
4SearchName = "" or Index(ToLower(Employee.FirstName + " " + Employee.LastName), ToLower(SearchName), 0) >= 0
5
6/* Search by last name only */
7SearchName = "" or Index(ToLower(Employee.LastName), ToLower(SearchName), 0) >= 0
8
9/* Email contains search (partial match) */
10SearchEmail = "" or Index(ToLower(Employee.Email), ToLower(SearchEmail), 0) >= 0
11
12/* Exact match (faster — uses index) */
13SearchName = "" or Employee.LastName = SearchName

Add a second filter for Department: `FilterDepartmentId = NullIdentifier() or Employee.DepartmentId = FilterDepartmentId` When FilterDepartmentId = NullIdentifier() (default), all departments pass. When a specific department is selected, only that department's employees appear. Add date range filters (two separate filter conditions): `FilterHireDateFrom = NullDate() or Employee.HireDate >= FilterHireDateFrom` `FilterHireDateTo = NullDate() or Employee.HireDate <= FilterHireDateTo` All three filters work together: the Aggregate returns employees matching ALL active filter conditions (text search AND department AND date range). In the screen, bind Input widgets: - Text Input → Variable: SearchName → OnChange: Client Action to Refresh Data - Dropdown → Variable: FilterDepartmentId → OnChange: Refresh Aggregate - DatePicker → Variable: FilterHireDateFrom → OnChange: Refresh Aggregate

1/* Multiple optional filter conditions in Filters tab */
2/* All conditions are AND'd automatically */
3
4/* Condition 1: Text search */
5SearchName = "" or Index(ToLower(Employee.FirstName + " " + Employee.LastName), ToLower(SearchName), 0) >= 0
6
7/* Condition 2: Department dropdown */
8FilterDepartmentId = NullIdentifier() or Employee.DepartmentId = FilterDepartmentId
9
10/* Condition 3: Hire date from */
11FilterHireDateFrom = NullDate() or Employee.HireDate >= FilterHireDateFrom
12
13/* Condition 4: Hire date to */
14FilterHireDateTo = NullDate() or Employee.HireDate <= FilterHireDateTo
15
16/* Condition 5: Active status (always applied — not optional) */
17Employee.IsActive = FilterIsActive

Filters in the Aggregate read variable values at the time the Aggregate runs. Changing a variable does NOT automatically re-run the Aggregate — you must trigger a refresh. For a search-as-you-type pattern: 1. Select the Search Input widget on screen 2. In Properties → Events → OnChange → click the lightning bolt → New Client Action 3. Name it 'OnSearchChange' 4. In the action flow: Start → Refresh Data (drag from Toolbox, select GetEmployees) → End For a 'Search' button click: 1. Button → OnClick → New Client Action 2. Action flow: Start → Assign StartIndex = 0 (reset pagination) → Refresh Data: GetEmployees → End For multiple filters triggering at once, one Refresh Data node is sufficient — OutSystems re-runs the entire Aggregate with all current variable values.

1/* Client Action: OnSearchChange */
2/* Start
3   → Refresh Data: GetEmployees
4   → End */
5
6/* Client Action: OnFilterApply (button click) */
7/* Start
8   → Assign: StartIndex = 0          (reset to page 1)
9   → Refresh Data: GetEmployees
10   → End */
11
12/* Client Action: OnClearFilters */
13/* Start
14   → Assign: SearchName = ""         (clear text)
15   → Assign: FilterDepartmentId = NullIdentifier()
16   → Assign: FilterHireDateFrom = NullDate()
17   → Assign: FilterHireDateTo = NullDate()
18   → Refresh Data: GetEmployees
19   → End */

To search across multiple fields simultaneously (e.g., name OR email), combine conditions within a single filter expression using the `or` keyword: `SearchName = "" or Index(ToLower(Employee.FirstName + " " + Employee.LastName), ToLower(SearchName), 0) >= 0 or Index(ToLower(Employee.Email), ToLower(SearchName), 0) >= 0` This is a single filter condition (one entry in the Filters tab) using multiple `or` sub-conditions — NOT three separate filter entries (which would AND them). For complex OR logic spanning multiple entities (e.g., search employee name OR department name), keep it as one expression: `SearchName = "" or Index(ToLower(Employee.LastName), ToLower(SearchName), 0) >= 0 or Index(ToLower(Department.Name), ToLower(SearchName), 0) >= 0`

1/* Single filter expression with OR conditions */
2/* Multi-field search: matches name OR email OR department */
3
4SearchName = ""
5or Index(ToLower(Employee.FirstName + " " + Employee.LastName), ToLower(SearchName), 0) >= 0
6or Index(ToLower(Employee.Email), ToLower(SearchName), 0) >= 0
7or Index(ToLower(Department.Name), ToLower(SearchName), 0) >= 0
8
9/* Key rule:
10   Multiple filter ENTRIES in the Filters tab = AND logic
11   Multiple conditions in ONE filter entry = you control AND/OR with operators */