ClickHouse Functions

ClickHouse function reference for TypeScript developers

A curated set of common ClickHouse functions for analytics, with SQL and hypequery examples for date bucketing, aggregation, string manipulation, conditionals, and numeric bucketing.

Quick start ClickHouse TypeScript guide

Functions covered

Clusters

Date · Aggregate · String · Conditional · Math

Each page includes

SQL + query-builder examples

Date Functions

Date and time functions for bucketing, truncating, and formatting timestamps — the foundation of every ClickHouse analytics query.

toStartOfDay()

Truncate a DateTime to midnight — the foundation of daily analytics bucketing.

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toStartOfWeek()

Round a DateTime to the start of the week — weekly cohort and trend analysis.

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toStartOfMonth()

Truncate a DateTime to the first day of the month for MoM reporting.

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toStartOfQuarter()

Round a DateTime to the first day of the quarter for QoQ reporting.

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toStartOfInterval()

Bucket by any arbitrary interval — 5-minute, hourly, bi-weekly, or custom.

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now()

Return the current server DateTime — the anchor for relative time filters.

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toDate()

Convert a string or DateTime to a ClickHouse Date value.

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formatDateTime()

Format a DateTime as a string using strftime-style patterns.

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Aggregate Functions

Aggregate functions for counting, summing, averaging, and estimating cardinality across millions of rows.

count()

Count rows or non-NULL values — ClickHouse's fastest aggregate.

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uniq()

Approximate distinct count — fast cardinality estimation for DAU and unique visitors.

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sum()

Sum numeric values — revenue totals, event counts, and metric roll-ups.

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avg()

Calculate the arithmetic mean — average order value, session duration, latency.

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quantile()

Percentile estimates — p50, p95, p99 for latency and performance metrics.

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groupArray()

Collect values into an array — session stitching, event sequences, and path analysis.

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String Functions

String manipulation functions for formatting display values, parsing, and building composite keys.

toString()

Cast any ClickHouse value to a String — the universal type conversion function.

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concat()

Concatenate strings — build labels, composite keys, and display values.

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Conditional Functions

Conditional expressions for inline branching, NULL handling, and multi-way value selection.

if()

Inline conditional — the ternary operator of ClickHouse SQL.

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multiIf()

Multi-branch conditional — clean CASE WHEN replacement for status mapping.

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Math Functions

Math functions for rounding, integer arithmetic, and numeric bucketing.

round()

Round a number to N decimal places — clean display values and bucketing.

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intDiv()

Integer division — bucket IDs, page numbers, and fixed-width range grouping.

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Get started

Use common ClickHouse functions in typed TypeScript queries

hypequery generates a TypeScript schema from your live ClickHouse database. These examples show how to combine ClickHouse functions with the query builder, while using raw SQL expressions when the function is not wrapped by a dedicated helper.

Quick start TypeScript guide