Need operator for "substring" on value or array of values

[JozefAerts]

Standard

CDISC SEND

Reference Rule ID(s)

SEND-406

Conformance Rule ID(s) (if published in CORE)

No response

JIRA Ticket

https://jira.cdisc.org/projects/CORERULES/issues/CORERULES-

Proposed Rule YAML

N/A see SEND406 in old rule-editor

Attach any sample test data file(s)

for SEND406, we need to take all the values of SJSTDTC for each subject, which usually is a datetime, but not always, and only take the date part, and of these, take the lowest value. I did not find an operator representing "substring" though. I tried with "min_date" but it throws an error when there is a mixture of dates and datetimes.

SENDIG_406_positive.xlsx

Expected output

date part (substring($x,1,10) of a datetime when > 10 character, original value when 10 characters.

Any Additional Information

No response