Scalar Functions — DateTime

KQL has a rich set of datetime functions for bucketing, truncating, formatting, and converting timestamps. Most functions work across all four dialects. SQLite has the most gaps, particularly for datetime_diff(), datetime_part(), and make_datetime(), which have no equivalent SQLite expression.

Legend: ✅ Supported · ⚠️ Approximated · ❌ Not Supported · 🔄 Rewritten

Function	SQLite	MySQL	ClickHouse	PostgreSQL	Notes
`now()`	✅	✅	✅	✅	SQLite: `datetime('now')`
`ago(duration)`	✅	✅	✅	✅	All units supported; sub-second normalized to seconds
`datetime(val)`	✅	✅	✅	✅
`todatetime()`	✅	✅	✅	✅	CAST to timestamp
`make_datetime()`	❌	✅	✅	✅	SQLite: unsupported
`datetime_diff()`	❌	✅	✅	✅	SQLite: unsupported
`datetime_add()`	⚠️	✅	✅	✅	SQLite: literal values only
`datetime_part()`	❌	✅	✅	✅	SQLite: unsupported
`format_datetime()`	✅	✅	✅	✅	Format tokens translated per dialect
`startofday()`	✅	✅	✅	✅
`startofmonth()`	✅	✅	✅	✅
`startofweek()`	✅	✅	✅	✅
`startofyear()`	✅	✅	✅	✅
`endofday()`	✅	✅	✅	✅
`endofmonth()`	✅	✅	✅	✅	SQLite: datetime modifier chain
`endofweek()`	✅	✅	✅	✅
`endofyear()`	✅	✅	✅	✅	SQLite: datetime modifier chain; MySQL: `TIMESTAMP(CONCAT(YEAR(ts),'-12-31 23:59:59'))`; Postgres: `date_trunc + interval`; ClickHouse: `endOfYear`
`dayofmonth()`	✅	✅	✅	✅
`dayofweek()`	✅	✅	✅	✅
`dayofyear()`	✅	✅	✅	✅
`hourofday()`	✅	✅	✅	✅
`monthofyear()`	✅	✅	✅	✅
`getyear()`	✅	✅	✅	✅
`weekofyear()`	✅	✅	✅	✅
`bin(col, interval)`	❌	✅	✅	⚠️	ClickHouse: `toStartOfInterval`; MySQL: `from_unixtime`; Postgres: TODO warning
`totimespan()`	⚠️	⚠️	✅	✅	SQLite/MySQL: approximated as raw seconds with warning
`format_timespan()`	⚠️	⚠️	✅	✅	ClickHouse: `formatReadableTimeDelta`; others: CAST to TEXT with warning
`unixtime_seconds_todatetime()`	✅	✅	✅	✅
`unixtime_milliseconds_todatetime()`	✅	✅	✅	✅	Divides by 1000
`unixtime_microseconds_todatetime()`	✅	✅	✅	✅	Divides by 1,000,000
`unixtime_nanoseconds_todatetime()`	✅	✅	✅	✅	Divides by 1,000,000,000