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Filter DataTable

Filters rows in a DataTable based on a filter expression. Only rows that match the filter criteria are included in the output table. This node is essential for data selection and conditional processing.

Common Properties​

  • Name - The custom name of the node.
  • Color - The custom color of the node.
  • Delay Before (sec) - Waits in seconds before executing the node.
  • Delay After (sec) - Waits in seconds after executing node.
  • Continue On Error - Automation will continue regardless of any error. The default value is false.
info

If the ContinueOnError property is true, no error is caught when the project is executed, even if a Catch node is used.

Input​

  • Table - DataTable to filter
  • Filter - Filter expression to apply (uses DataView RowFilter syntax)

Output​

  • Table - Filtered DataTable containing only rows that match the filter criteria

Filter Expression Syntax​

The filter uses .NET DataView RowFilter syntax. Here are common patterns:

Comparison Operators​

  • = - Equal to
  • <> - Not equal to
  • > - Greater than
  • >= - Greater than or equal to
  • < - Less than
  • <= - Less than or equal to

Logical Operators​

  • AND - Both conditions must be true
  • OR - At least one condition must be true
  • NOT - Negates a condition

String Operations​

  • String values must be enclosed in single quotes: 'value'
  • LIKE - Pattern matching with wildcards (% for multiple chars, _ for single char)

Wildcards​

  • % - Matches any sequence of characters
  • * - Can also be used in some contexts
  • _ - Matches any single character

Example Usage​

Simple Equality Filter​

// Filter by exact match
var filter = "Status = 'Active'";

// Result: Only rows where Status column equals 'Active'

Numeric Comparisons​

// Filter by age range
var filter = "Age > 18 AND Age < 65";

// Filter by minimum value
var filter = "Salary >= 50000";

// Filter by price range
var filter = "Price > 10.00 AND Price <= 100.00";

String Pattern Matching​

// Find all emails from gmail
var filter = "Email LIKE '%@gmail.com'";

// Find names starting with 'A'
var filter = "Name LIKE 'A%'";

// Find names containing 'son'
var filter = "Name LIKE '%son%'";

// Find exact length patterns
var filter = "Code LIKE 'AB____'";  // Matches AB followed by 4 chars

Multiple Conditions​

// Combine multiple conditions with AND
var filter = "Department = 'Sales' AND Salary > 60000";

// Use OR for alternative conditions
var filter = "Status = 'Active' OR Status = 'Pending'";

// Complex combinations
var filter = "(Age > 25 AND Age < 40) AND (City = 'New York' OR City = 'Boston')";

NOT Operator​

// Exclude specific values
var filter = "NOT Status = 'Deleted'";

// Exclude pattern
var filter = "NOT Email LIKE '%@spam.com'";

Filtering with Dynamic Values​

// Build filter from variables
var minAge = 21;
var department = "Engineering";
var filter = "Age >= " + minAge + " AND Department = '" + department + "'";

// Filter: "Age >= 21 AND Department = 'Engineering'"

Date Filtering​

// Filter by date (format as per your data)
var filter = "OrderDate >= '2024-01-01' AND OrderDate <= '2024-12-31'";

// Recent records
var filter = "CreatedDate > '2024-06-01'";

Tips​

  • Always enclose string values in single quotes ('value')
  • Use parentheses to group complex conditions
  • Column names with spaces should be enclosed in square brackets: [Column Name] = 'value'
  • Test your filter expressions with sample data first
  • The filter is case-sensitive for string comparisons
  • Empty or null values can be checked with special syntax: ColumnName IS NULL
  • For "not null": ColumnName IS NOT NULL
  • Original table is not modified; a new filtered table is returned

Common Errors​

Empty Table Error​

Error: Table cannot be empty. Please provide a valid DataTable.

Solution: Ensure you're passing a valid DataTable object.

// Wrong - table is null
var table = null;

// Correct
var table = /* Valid DataTable */;

Empty Filter Error​

Error: Filter cannot be empty. Please provide a valid filter expression (e.g., age > 30).

Solution: Provide a valid filter expression string.

// Wrong
var filter = "";

// Correct
var filter = "Age > 30";

Invalid Filter Syntax​

Error: Various syntax errors from the DataView engine

Common causes and solutions:

// Wrong - missing quotes around string
var filter = "Name = John";  // Error!

// Correct
var filter = "Name = 'John'";

// Wrong - using double quotes
var filter = 'Name = "John"';  // May cause error

// Correct - use single quotes
var filter = "Name = 'John'";

// Wrong - invalid operator
var filter = "Age == 30";  // Use = not ==

// Correct
var filter = "Age = 30";

Column Name Not Found​

If you reference a column that doesn't exist in the table, you'll get an error.

// Table has columns: ["Name", "Age", "Email"]

// Wrong - column doesn't exist
var filter = "Status = 'Active'";  // Error: Status column not found

// Correct
var filter = "Name = 'John'";

Advanced Examples​

Multiple Value Matching​

// Match any of several values (using OR)
var filter = "Country = 'USA' OR Country = 'Canada' OR Country = 'Mexico'";

// Using IN operator (if supported)
var filter = "Country IN ('USA', 'Canada', 'Mexico')";

Null Checks​

// Find rows with null values
var filter = "PhoneNumber IS NULL";

// Find rows with non-null values
var filter = "PhoneNumber IS NOT NULL";

// Combine with other conditions
var filter = "Email IS NOT NULL AND Status = 'Active'";

See Also​