APIv4 - Support pseudoconstant suffixes in orderBy clause

[colemanw]

Overview

Allows results from API get to be ordered by a suffix e.g. activity_type_id:label. Works for DAO entities as well as basic entities. Exposed to the API explorer.

Before

Could only order by field value, which would appear out of order when viewing the label.

After

Can order by label, name, color, etc.

Technical Details

Pseudoconstant substitution happens through the magic of MySql FIELD() function.

[civibot]

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