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- current-date(): a build-in function returning the current date value in ISO date string format.
- current-date-time(): a build-in function returning the current date time value in ISO date/time string format.
- max: a build-in function returning the max value out of an expression.
Further discussions
Ocean products have been using AQL to search and retrieve openEHR-conformed EHR data for couple of years. The major usages of AQL are:
- Retrieving candidate compositions with given criteria on EHR identifier and composition meta data, such as composition type (i.e. archetype id), healthcare facility, event start time, composer and so on.
- Retrieving EHR data from a single EHR for dedicated purposes, such as risk factor calculations
- Reporting, in which AQL is used to retrieve EHR data that are cross multiple EHRs, i.e. population AQL query.
- AQL might also be used for other purposes which are out of my knowledge. This list needs to be updated with new usages.