docs: misc docs and tests (MINOR) (#4375)

docs-md/developer-guide/syntax-reference.md

@@ -312,6 +312,20 @@ Mathematical operations between `DOUBLE` and `DECIMAL` cause the decimal to be
 converted to a double value automatically. Converting from the decimal data type
 to any floating point type (`DOUBLE`) may cause loss of precision.
 
+### Constants
+
+- **String constants** are enclosed in single quotation marks and may include any unicode
+character (e.g. `'hello'`, `'1.2'`).
+- **Integer constants** are represented by numbers that are not enclosed in quotation marks
+and do not contain decimal points (e.g. `1`, `2`).
+- **Decimal constants** are represented by a string of numbers that are no enclosed in quotation
+marks and contain a decimal point (e.g. `1.2`, `87.`, `.94`). The type of the decimal constant
+will be `DECIMAL(p, s)` where `p` is the total number of numeric characters in the string and
+`s` is the total number of numeric characters that appear to the right of the decimal point.
+- **Double constants** are numeric strings represented in scientific notation (e.g. `1E0`, `.42E-3`).
+- **Boolean constants** are the unquoted strings that are exactly (case-insensitive) `TRUE`
+or `FALSE`.
+
 SQL statements
 --------------
 

ksql-functional-tests/src/test/resources/query-validation-tests/quoted-identifiers.json

@@ -74,6 +74,19 @@
         ]
       }
     },
+    {
+      "name": "partition by quoted field",
+      "statements": [
+        "CREATE STREAM TEST (`some.key` VARCHAR) WITH (kafka_topic='test_topic', value_format='JSON');",
+        "CREATE STREAM OUTPUT AS SELECT * FROM TEST PARTITION BY `some.key`;"
+      ],
+      "inputs": [
+        {"topic": "test_topic", "value": {"some.key": "key"}}
+      ],
+      "outputs": [
+        {"topic": "OUTPUT", "key": "key", "value": {"some.key": "key"}}
+      ]
+    },
     {
       "name": "joins using fields that require quotes",
       "statements": [