docs: Explain combining measure and dimension filters

Author: igorlukanin

docs/pages/guides/dbt.mdx

@@ -299,7 +299,7 @@ cubes:
         type: count
 
       - name: statuses
-        sql: "STRING_AGG({status})"
+        sql: "STRING_AGG({status}, ',')"
         type: string
 
     # Model-specific joins

docs/pages/product/apis-integrations/rest-api/query-format.mdx

@@ -520,8 +520,11 @@ only one of the following properties:
 }
 ```
 
-> **Note:** You can not put dimensions and measures filters in the same logical
-> operator.
+**You can not put dimensions and measures filters in the same logical operator.**
+When Cube generates a SQL query to the data source, dimension and measure filters
+are translated to expressions in `WHERE` and `HAVING` clauses, respectively.  
+In other words, dimension filters apply to raw (unaggregated) data and measure filters
+apply to aggregated data, so it's not possible to express such filters in SQL semantics.
 
 ## Time Dimensions Format