Merge pull request 'docs(filter): the applied clause carries SAS temporal literals' (#20) from docs/filter-date-literals into main

Reviewed-on: #20

docs/filter.md

@@ -9,6 +9,8 @@ og_image:  https://docs.datacontroller.io/img/filter_dynamic_on.png
 
 Data Controller for SAS® enables you to create complex table filters. The "dynamic" setting enables the dropdown values to be pre-filtered by previous filter clauses.  Filtered views are shareable!  They are also used when [embedded in VA.](/embed-va)
 
+The clause shown above the grid is the resolved WHERE clause that was applied, so it uses SAS syntax - a date, datetime or time filter reads as a SAS literal, eg `SOME_DATE = '20APR2042'd`, rather than the internal day or second count.
+
 ## Shared Filters
 
 When filters are submitted, the query is stored, and a unique URL is generated.  This means you can share the link to a filtered view of a table!  This can be used for VIEW, for EDIT and also for downloading data.

docs/tables/mpe_filtersource.md

@@ -17,5 +17,5 @@ The `MPE_FILTERSOURCE` table stores the individual query lines of each filter cr
  - `SUBGROUP_ID num`: Identifier of the subgroup to which this line belongs
  - `VARIABLE_NM char(32)`: The variable being filtered
  - `OPERATOR_NM char(12)`: The filter operator (e.g. `=`, `>`, `IN`)
- - `RAW_VALUE char(4000)`: The filter value
+ - `RAW_VALUE char(4000)`: The filter value. A date, datetime or time is stored as a SAS literal (for example `'20APR2042'd`, `'01JAN1960:00:00:42'dt`, `'00:00:42't`), so the clause shown above the grid reads as a date rather than the internal day or second count.
  - `PROCESSED_DTTM num`: Datetime the filter line was created