Function Expressions

Querity supports SQL-like functions in filters, sorting, and projections. Use prop() for property references and lit() for literal values.

Using functions in filters

import static io.github.queritylib.querity.api.Querity.*;

// Filter by uppercase lastName
Query query = Querity.query()
    .filter(filterBy(upper(prop("lastName")), EQUALS, "SKYWALKER"))
    .build();

// Filter by string length
Query query = Querity.query()
    .filter(filterBy(length(prop("firstName")), GREATER_THAN, 5))
    .build();

// Filter by a computed value (quantity * unitPrice)
Query query = Querity.query()
    .filter(filterBy(multiply(prop("quantity"), prop("unitPrice")), GREATER_THAN, 1000))
    .build();

Using functions in sorting

// Sort by string length
Query query = Querity.query()
    .sort(sortBy(length(prop("lastName")), DESC))
    .build();

// Sort by uppercase value
Query query = Querity.query()
    .sort(sortBy(upper(prop("firstName"))))
    .build();

Using functions in projections

// Select with function expressions
AdvancedQuery query = Querity.advancedQuery()
    .select(selectBy(
        prop("id"),
        upper(prop("lastName")).as("upperLastName"),
        concat(prop("firstName"), lit(" "), prop("lastName")).as("fullName"),
        length(prop("email")).as("emailLength")
    ))
    .build();

Available functions

Category	Functions
Arithmetic	abs(), sqrt(), mod(), add(), subtract(), multiply(), divide(), negate()
String	concat(), substring(), trim(), ltrim(), rtrim(), lower(), upper(), length(), locate()
Date/Time	currentDate(), currentTime(), currentTimestamp()
Conditional	coalesce(), nullif()
Aggregate	count(), sum(), avg(), min(), max()

Function arguments

Function arguments must be either property references or literals:

• prop("fieldName") - reference to an entity property (alias for property())
• lit(value) - literal value (String, Number, or Boolean)

// Combine functions
coalesce(prop("nickname"), lit("Anonymous"))
mod(prop("quantity"), lit(10))
concat(prop("firstName"), lit(" - "), prop("lastName"))

// Arithmetic functions
add(prop("basePrice"), prop("shippingCost"))          // variadic: 2+ arguments
multiply(prop("quantity"), prop("unitPrice"))         // variadic: 2+ arguments
subtract(prop("price"), lit(10))                      // binary: exactly 2 arguments
divide(prop("total"), prop("count"))                  // binary: exactly 2 arguments
negate(prop("balance"))                               // unary: exactly 1 argument

// SUBTRACT and DIVIDE are strictly binary; express chains by nesting
subtract(subtract(prop("total"), prop("discount")), prop("tax"))  // (total - discount) - tax

// Nested functions
upper(trim(prop("name")))  // UPPER(TRIM(name))
length(lower(prop("email")))  // LENGTH(LOWER(email))

// Nested properties (e.g., address.city)
upper(prop("address.city"))
coalesce(prop("contact.email"), prop("contact.phone"), lit("N/A"))

Note: with integer operands, divide() follows the backend’s integer-division semantics (e.g. divide(lit(7), lit(2)) may yield 3).

Backend support for functions

• JPA: Full support for all functions in filters, sorting, and projections
• MongoDB: Functions supported in filters only (via $expr). Using functions in sort or select throws UnsupportedOperationException
• Elasticsearch: Functions are not supported. Using functions throws UnsupportedOperationException

Function support by implementation:

Function	JPA	MongoDB	Elasticsearch
abs(), sqrt(), mod()	✓ Filters, Sort, Select	✓ Filters only	✗
add(), subtract(), multiply(), divide(), negate()	✓ Filters, Sort, Select	✓ Filters only	✗
concat(), substring(), trim(), ltrim(), rtrim()	✓ Filters, Sort, Select	✓ Filters only	✗
lower(), upper(), length(), locate()	✓ Filters, Sort, Select	✓ Filters only	✗
currentDate(), currentTime(), currentTimestamp()	✓ Filters, Sort, Select	✓ Filters only	✗
coalesce(), nullif()	✓ Filters, Sort, Select	✓ Filters only	✗
count(), sum(), avg(), min(), max()	✓ Filters, Sort, Select	✓ Filters only	✗