Tools And Features Hogql Agent Skill

by PostHog

HogQL queries for PostHog analytics

19k tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/PostHog/skills --skill tools-and-features-hogql

What comes with it

71 752 bytes besides the instruction

references/aggregations.md

references/clickhouse-functions.md

references/data-access.md

references/expressions.md

references/posthog.md

references/sessions.md

references/useful-functions.md

references/variables.md

The instruction itself

8 sections, as written by the author

HogQL queries for PostHog

This skill helps you write HogQL queries for PostHog analytics. HogQL is PostHog's SQL dialect, a wrapper around ClickHouse SQL with simplified property access and PostHog-specific functions.

Reference files

references/expressions.md - Sql expressions - docs
references/aggregations.md - Supported aggregations - docs
references/clickhouse-functions.md - Supported clickhouse functions - docs
references/data-access.md - Accessing data using sql - docs
references/variables.md - Sql variables - docs
references/useful-functions.md - Useful sql functions - docs
references/posthog.md - PostHog table schemas (events, persons, groups, sessions)
references/sessions.md - Sessions - docs

Consult the documentation for SQL syntax, available functions, and query patterns.

Key principles

Property access: Use properties.$property_name for event properties and person.properties.$property_name for person properties
Null handling: HogQL has simplified null handling compared to raw ClickHouse SQL
Filters placeholder: Use {filters} in queries to allow UI-based filtering in PostHog dashboards
Aggregations: Prefer ClickHouse aggregation functions like count(), uniq(), avg(), sum()

Common patterns

Event queries

SELECT event, count()
FROM events
WHERE {filters}
GROUP BY event
ORDER BY count() DESC

Property breakdowns

SELECT properties.$browser AS browser, count()
FROM events
WHERE event = '$pageview' AND {filters}
GROUP BY browser

Person properties

SELECT person.properties.email, count()
FROM events
WHERE {filters}
GROUP BY person.properties.email

Framework guidelines

Use properties.$name syntax for event properties, person.properties.$name for person properties
Use bracket notation for special characters like properties['$feature/cool-flag']
For cohorts, filter with person_id IN COHORT 'cohort-name'
For actions, use matchesAction('action-name') in WHERE clauses
Include {filters} placeholder in WHERE clauses to enable UI-based filtering in dashboards
Use {variables.name} for reusable SQL variables across dashboards
Access dashboard date range with {filters.dateRange.from} and {filters.dateRange.to}
ALWAYS include a time range filter - shorter is faster (e.g., timestamp >= now() - INTERVAL 7 DAY)
Prefer uniq() over count(distinct) for counting unique values - it's more efficient
Don't scan the same table multiple times - use materialized views for reusable subsets
Use timestamp-based pagination instead of OFFSET for large datasets
Name queries descriptively for easier debugging in query_log
Use dateTrunc() for time-based grouping (e.g., dateTrunc('day', timestamp))
For funnel queries, use windowFunnel() or sequenceMatch() functions
Test queries in the PostHog SQL editor before using them in insights or the API

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How to use it

Copy the folder

Take posthog/tools-and-features-hogql from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

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