HealthQL

A SQL-like query language for Apple HealthKit. Query your health data using familiar SQL syntax or a type-safe Swift DSL.

SELECT avg(value), min(value), max(value)
FROM heart_rate
WHERE date > today() - 7d
GROUP BY day

Features

• SQL-like Syntax - Query HealthKit with familiar SELECT, FROM, WHERE, GROUP BY, ORDER BY, LIMIT
• Type-safe Swift DSL - Fluent API for building queries programmatically
• 18 Quantity Types - Heart rate, steps, calories, distance, weight, and more
• 5 Category Types - Sleep analysis, headache, fatigue, appetite, menstrual flow
• Workouts & Sleep Sessions - Query exercise data and aggregated sleep metrics
• Date Functions - today(), start_of_week(), start_of_month(), start_of_year()
• Aggregations - SUM, AVG, MIN, MAX, COUNT with GROUP BY support
• Full Predicate Support - All comparison operators, AND, IS NULL, IS NOT NULL

Installation

Swift Package Manager

Add HealthQL to your Package.swift:

dependencies: [
    .package(url: "https://github.com/glisom/HealthQL.git", from: "1.0.0")
]

Then add the products you need:

.target(
    name: "YourApp",
    dependencies: [
        "HealthQL",        // Core types and execution
        "HealthQLParser",  // SQL string parsing
    ]
)

Quick Start

SQL String Queries

import HealthQL
import HealthQLParser

// Parse and execute a query
let result = try await HQL.query("""
    SELECT sum(value) FROM steps
    WHERE date > today() - 7d
    GROUP BY day
""")

for row in result.rows {
    print("\(row["date"]!): \(row["sum_value"]!) steps")
}

Swift DSL

import HealthQL

let result = try await Health.select(.steps, aggregate: .sum)
    .where(.date, .greaterThan, .date(.daysAgo(7)))
    .groupBy(.day)
    .execute()

Supported Health Types

Quantity Types

Type	SQL Name	Unit
Heart Rate	heart_rate	bpm
Steps	steps	count
Active Calories	active_calories	kcal
Resting Calories	resting_calories	kcal
Distance	distance	m
Flights Climbed	flights_climbed	count
Stand Time	stand_time	min
Exercise Minutes	exercise_minutes	min
Body Mass	body_mass	kg
Height	height	m
Body Fat %	body_fat_percentage	%
HRV	heart_rate_variability	ms
Blood Oxygen	oxygen_saturation	%
Respiratory Rate	respiratory_rate	/min
Body Temperature	body_temperature	°C
Blood Pressure (Sys)	blood_pressure_systolic	mmHg
Blood Pressure (Dia)	blood_pressure_diastolic	mmHg
Blood Glucose	blood_glucose	mg/dL

Category Types

Type	SQL Name
Sleep Analysis	sleep_analysis
Appetite Changes	appetite_changes
Headache	headache
Fatigue	fatigue
Menstrual Flow	menstrual_flow

Special Types

Type	SQL Name	Description
Workouts	workouts	Exercise sessions with duration, calories, type
Sleep Sessions	sleep	Aggregated nightly sleep with stage breakdown

Query Examples

Basic Queries

-- All heart rate readings from today
SELECT * FROM heart_rate WHERE date > today()

-- Latest 10 weight measurements
SELECT value, date FROM body_mass ORDER BY date DESC LIMIT 10

-- Steps with source device info
SELECT value, date, source, device FROM steps WHERE date > today() - 7d

Aggregations

-- Daily step totals for the past month
SELECT sum(value) FROM steps WHERE date > today() - 30d GROUP BY day

-- Weekly average heart rate
SELECT avg(value), min(value), max(value) FROM heart_rate
WHERE date > start_of_month() GROUP BY week

-- Monthly calorie burn
SELECT sum(value) FROM active_calories WHERE date > start_of_year() GROUP BY month

Workouts

-- Recent workouts with details
SELECT duration, total_calories, activity_type FROM workouts
ORDER BY date DESC LIMIT 20

-- Weekly workout summary
SELECT sum(duration), sum(total_calories) FROM workouts
WHERE date > today() - 30d GROUP BY week

Sleep

-- Sleep sessions for the past week
SELECT * FROM sleep WHERE date > today() - 7d ORDER BY date DESC

-- Raw sleep analysis data
SELECT * FROM sleep_analysis WHERE date > today() - 7d

Filtering

-- High heart rate readings
SELECT * FROM heart_rate WHERE value > 100

-- Heart rate in normal range
SELECT * FROM heart_rate WHERE value > 60 AND value < 100

-- Readings with device info
SELECT * FROM heart_rate WHERE device IS NOT NULL

Date Functions

Function	Description
today()	Start of current day
start_of_week()	Start of current week
start_of_month()	Start of current month
start_of_year()	Start of current year

Duration Syntax

Unit	Syntax	Example
Days	d	7d
Weeks	w	4w
Months	mo	3mo
Years	y	1y

-- Last 7 days
WHERE date > today() - 7d

-- Last 4 weeks
WHERE date > today() - 4w

-- Last 3 months
WHERE date > today() - 3mo

Architecture

HealthQL uses a multi-stage architecture:

SQL String → Lexer → Parser → AST → Compiler → HealthQuery IR → Executor → Results
                                                      ↑
Swift DSL → QueryBuilder ──────────────────────────────┘

Modules

Module	Purpose
HealthQL	Core types, IR, DSL, HealthKit execution
HealthQLParser	SQL lexer, parser, compiler
HealthQLPlayground	REPL engine, formatting, autocomplete

Requirements

• iOS 15.0+ / macOS 13.0+
• Swift 6.0+
• HealthKit entitlement

HealthKit Setup

1. Add HealthKit capability to your app
2. Add usage descriptions to Info.plist:

<key>NSHealthShareUsageDescription</key>
<string>Read health data to display query results</string>

3. Request authorization (HealthQL requests automatically on first query, or manually):

let store = HKHealthStore()
try await store.requestAuthorization(toShare: [], read: [
    HKQuantityType(.heartRate),
    HKQuantityType(.stepCount),
    // ... other types
])

Example App

The HealthQLApp directory contains a sample iOS app demonstrating:

• Query input with syntax highlighting
• Demo query buttons for common queries
• Result display with formatting
• HealthKit authorization flow

License

MIT License - see LICENSE file for details.

Contributing

Contributions welcome! Please read the contributing guidelines before submitting PRs.

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Built with Swift and HealthKit.