# ago

This section contains reference documentation for the ago function.

Return time as epoch millis before the given period (in ISO-8601 duration format).

Examples:

"PT20.345S" -- parses as "20.345 seconds"

"PT15M" -- parses as "15 minutes" (where a minute is 60 seconds)

"PT10H" -- parses as "10 hours" (where an hour is 3600 seconds)

"P2D" -- parses as "2 days" (where a day is 24 hours or 86400 seconds)

"P2DT3H4M" -- parses as "2 days, 3 hours and 4 minutes"

"P-6H3M" -- parses as "-6 hours and +3 minutes"

"-P6H3M" -- parses as "-6 hours and -3 minutes"

"-P-6H+3M" -- parses as "+6 hours and -3 minutes"

Signature

ago()

Usage Examples

```
select ago("P1D") AS oneDayAgo
FROM ignoreMe
```

This function is typically used in predicate to filter on timestamp for recent data. e.g. filter data on recent 1 day.

```
SELECT *
FROM tableName
WHERE tsInMillis > ago("P1D")
```