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Filter Operations

Filtering is where OData starts to feel powerful: you describe the rows you want, and Portway translates that into SQL for you. This reference covers every supported filter operation, with examples you can adapt and a few practices that keep queries fast.

Filter Syntax ​

Basic filter structure:

txt
$filter=expression

Comparison Operators ​

Equality Operators ​

Operator Description Example
eq Equal to $filter=Status eq 'Active'
ne Not equal to $filter=Status ne 'Closed'

Examples ​

http
# String equality
GET /api/500/Products?$filter=ItemCode eq 'PROD001'

# Numeric equality
GET /api/500/Products?$filter=Price eq 99.99

# Boolean equality
GET /api/500/Products?$filter=IsActive eq true

# Date equality
GET /api/500/Orders?$filter=OrderDate eq 2024-01-15

Relational Operators ​

Operator Description Example
gt Greater than $filter=Price gt 100
ge Greater than or equal to $filter=Price ge 100
lt Less than $filter=Price lt 100
le Less than or equal to $filter=Price le 100

Examples ​

http
# Numeric comparison
GET /api/500/Products?$filter=Price gt 50.00

# Date comparison
GET /api/500/Orders?$filter=OrderDate gt 2024-01-01

# String comparison (alphabetical)
GET /api/500/Customers?$filter=Name gt 'M'

Logical Operators ​

Combining Conditions ​

Operator Description Example
and Logical AND $filter=Price gt 100 and Status eq 'Active'
or Logical OR $filter=Status eq 'New' or Status eq 'Pending'
not Logical NOT $filter=not contains(Description,'test')

Examples ​

http
# AND condition
GET /api/500/Products?$filter=Price gt 100 and Category eq 'Electronics'

# OR condition
GET /api/500/Orders?$filter=Status eq 'Pending' or Status eq 'Processing'

# NOT condition
GET /api/500/Products?$filter=not IsDeleted

# Complex combination
GET /api/500/Products?$filter=(Price gt 100 and Price lt 500) or Category eq 'Special'

Grouping with Parentheses ​

Use parentheses to control operator precedence:

http
# Without parentheses (AND has precedence over OR)
GET /api/500/Products?$filter=Price gt 100 and Category eq 'A' or Category eq 'B'
# Evaluates as: (Price gt 100 AND Category eq 'A') OR Category eq 'B'

# With parentheses
GET /api/500/Products?$filter=Price gt 100 and (Category eq 'A' or Category eq 'B')
# Evaluates as: Price gt 100 AND (Category eq 'A' OR Category eq 'B')

String Functions ​

Text Search Functions ​

Function Description Example
contains(field,value) Contains substring $filter=contains(Description,'widget')
startswith(field,value) Starts with string $filter=startswith(Name,'A')
endswith(field,value) Ends with string $filter=endswith(Email,'.com')

Examples ​

http
# Contains search (case-sensitive)
GET /api/500/Products?$filter=contains(Description,'book')

# Starts with
GET /api/500/Customers?$filter=startswith(Name,'John')

# Ends with
GET /api/500/Documents?$filter=endswith(FileName,'.pdf')

# Combining string functions
GET /api/500/Products?$filter=contains(Description,'premium') and startswith(ItemCode,'P')

All string comparisons are case-sensitive. startswith is typically faster than contains because it can use index range scans. There is no wildcard syntax, use contains, startswith, or endswith instead.

Working with Data Types ​

String Values ​

Strings are enclosed in single quotes:

http
# Correct
$filter=Name eq 'John Smith'

# Escape single quotes with another single quote
$filter=Description eq 'It''s a product'

# Multiple words
$filter=Category eq 'Home & Garden'

Numeric Values ​

Numbers don't require quotes:

http
# Integer
$filter=Quantity eq 10

# Decimal
$filter=Price eq 99.99

# Negative numbers
$filter=Balance gt -100.50

# Scientific notation
$filter=Value lt 1.5e6

Date and DateTime Values ​

Use ISO 8601 format:

http
# Date only
$filter=OrderDate eq 2024-01-15

# DateTime
$filter=CreatedAt gt 2024-01-15T14:30:00Z

# Date range
$filter=OrderDate ge 2024-01-01 and OrderDate lt 2024-02-01

Boolean Values ​

Use lowercase true or false:

http
# Boolean true
$filter=IsActive eq true

# Boolean false
$filter=IsDeleted eq false

# Negation
$filter=not IsActive

Null Values ​

Use null keyword:

http
# Check for null
$filter=AssignedTo eq null

# Check for not null
$filter=CompletedDate ne null

# Combine with other conditions
$filter=Status eq 'Open' and AssignedTo eq null

Advanced Filter Patterns ​

Range Queries ​

http
# Numeric range
GET /api/500/Products?$filter=Price ge 100 and Price le 500

# Date range
GET /api/500/Orders?$filter=OrderDate ge 2024-01-01 and OrderDate lt 2024-02-01

# Excluding boundaries
GET /api/500/Products?$filter=Price gt 100 and Price lt 500

Multiple Value Matching ​

http
# Using OR for multiple values
GET /api/500/Orders?$filter=Status eq 'New' or Status eq 'Pending' or Status eq 'Processing'

# Alternative approach with grouping
GET /api/500/Products?$filter=(Category eq 'A' or Category eq 'B' or Category eq 'C') and Price gt 50

Complex Text Searches ​

http
# Multiple text conditions
GET /api/500/Products?$filter=contains(Description,'premium') and not contains(Description,'refurbished')

# Search in multiple fields
GET /api/500/Products?$filter=contains(Name,'widget') or contains(Description,'widget')

Nested Conditions ​

http
# Complex nested logic
GET /api/500/Orders?$filter=(Status eq 'Open' and Priority eq 1) or (Status eq 'Pending' and DueDate lt 2024-02-01)

# Multiple grouping levels
GET /api/500/Products?$filter=((Price gt 100 and Price lt 500) or Category eq 'Special') and IsActive eq true

Filter Performance Tips ​

1. Use Indexed Fields ​

Always filter on indexed fields when possible:

http
# Good - filtering on primary key
GET /api/500/Products?$filter=ItemCode eq 'PROD001'

# Less efficient - filtering on non-indexed field
GET /api/500/Products?$filter=contains(Description,'long text search')

2. Avoid Complex String Operations ​

http
# Efficient - exact match
GET /api/500/Products?$filter=Category eq 'Electronics'

# Less efficient - contains operation
GET /api/500/Products?$filter=contains(Category,'Elec')

# Most efficient for prefix search
GET /api/500/Products?$filter=startswith(ItemCode,'PROD')

3. Limit Result Sets Early ​

http
# Good - filter reduces dataset before sorting
GET /api/500/Orders?$filter=Status eq 'Open'&$orderby=OrderDate desc&$top=10

# Less efficient - sorting entire dataset
GET /api/500/Orders?$orderby=OrderDate desc&$top=10

4. Use Specific Conditions ​

http
# Specific date
GET /api/500/Orders?$filter=OrderDate eq 2024-01-15

# Date range (less specific)
GET /api/500/Orders?$filter=OrderDate ge 2024-01-01 and OrderDate lt 2024-02-01

# Very broad (avoid)
GET /api/500/Orders?$filter=OrderDate ne null

Common Filter Patterns ​

Active Records ​

http
# Active items
GET /api/500/Products?$filter=IsActive eq true and IsDeleted eq false

# Non-deleted items
GET /api/500/Customers?$filter=DeletedDate eq null

Date-Based Filters ​

http
# Today's records
GET /api/500/Orders?$filter=OrderDate eq 2024-01-15

# This month's records
GET /api/500/Orders?$filter=OrderDate ge 2024-01-01 and OrderDate lt 2024-02-01

# Last 30 days
GET /api/500/Orders?$filter=OrderDate gt 2023-12-16

Status Filters ​

http
# Single status
GET /api/500/Tasks?$filter=Status eq 'Open'

# Multiple statuses
GET /api/500/Tasks?$filter=Status eq 'Open' or Status eq 'InProgress'

# Exclude status
GET /api/500/Tasks?$filter=Status ne 'Closed'

Search Patterns ​

http
# Partial match
GET /api/500/Products?$filter=contains(Name,'widget')

# Prefix search
GET /api/500/Customers?$filter=startswith(LastName,'Sm')

# Multiple field search
GET /api/500/Products?$filter=contains(Name,'phone') or contains(Description,'phone')

Error Handling ​

Common Filter Errors ​

  1. Invalid Field Name
json
{
  "error": "Invalid field name",
  "details": "Field 'InvalidField' is not allowed",
  "success": false
}
  1. Syntax Error
json
{
  "error": "Invalid filter syntax",
  "details": "Expected operator at position 15",
  "success": false
}
  1. Type Mismatch
json
{
  "error": "Type mismatch",
  "details": "Cannot compare string field with numeric value",
  "success": false
}
  1. Invalid Date Format
json
{
  "error": "Invalid date format",
  "details": "Date must be in ISO 8601 format",
  "success": false
}

Filter Limitations ​

Limitation Description Workaround
Query length Maximum 2048 characters Split into multiple queries
Filter complexity Maximum 10 conditions Simplify or split filters
String functions Case-sensitive only Handle case in application
No regex support No pattern matching Use contains/startswith
No arithmetic No calculations in filters Pre-calculate values
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Last updated: 2026-07-23

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