Add m as an alias to minute time duration

[costin]

Description

The minute timespan can be declared using minute, min and minutes. m should be added to the list.

FROM employees | WHERE @timestamp > NOW() - 1m

In addition, the docs should be updated to indicate that the space is not required between the digit and time unit - e.g. 1 d and 1d are the same.

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[jingwen-zjw]

Our team will take this issue and start working on it.

[Zachary-hub]

Credit: initial conflict observation by @Wentao14614.

Summary
Adding m as an alias for minute would be ambiguous with the existing month aliasing.

Findings

month already accepts m/mm, while minute accepts min/mi/n.
(see screenshot 1 – x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/scalar/date/DateDiff.java)

Matching is case-insensitive (toLowerCase(Locale.ROOT)), so M vs m cannot disambiguate.
(see screenshot 2 – x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/scalar/date/DateTimeField.java)

Whitespace between number and unit is optional (1m equals 1 m), so 1m would be ambiguous (month vs minute).

Conclusion
We should not add m -> minute.

Proposal (from our team; credit to @Wentao14614)
Keep the current convention (month: m/mm; minute: min/mi/n; millisecond: ms) and open a docs-only PR to:

list the existing aliases explicitly,

state case-insensitive matching,

reiterate that whitespace is optional,

show unambiguous minute examples (1mi, 1n) and 1ms for milliseconds.

Examples
FROM t | WHERE date_col > NOW() - 1m -- month (1m == 1 m)
FROM t | WHERE ts > NOW() - 1mi -- minute
FROM t | WHERE ts > NOW() - 1n -- minute
FROM t | WHERE ts > NOW() - 500ms -- millisecond

[Zachary-hub]

Opened a docs-only PR to clarify duration aliases and matching rules: #136426

[felixbarny]

I've tried the following queries and they all don't work:

FROM logs-* | WHERE @timestamp > now() - 1m
FROM logs-* | WHERE @timestamp > now() - 1n
FROM logs-* | WHERE @timestamp > now() - 1mi

I think you were looking at the wrong class for duration literals.

I've created a PR to add support for m as an alias for minutes here: #136448

[leemthompo]

@jingwen-zjw who is your team exactly?

[jingwen-zjw]

Our team consists of @Zachary-hub, @Wentao14614, @Shiqin723, and @XinyuYU0416. We’re all students from the Australian National University, and selecting and completing an issue in an open-source project is part of one of our course assignments. Hope this clarifies!