Serverless SQL Database: Update known-differences.mdx (#3762)

* Update known-differences.mdx

Fix and align wording on PostgreSQL commands which cannot be performed.
Add a workaround snippet regarding SET/RESET features inside a transaction.

* Apply suggestions from code review

Co-authored-by: Jessica <[email protected]>

---------

Co-authored-by: SamyOubouaziz <[email protected]>
Co-authored-by: Jessica <[email protected]>

Author: 3 people

serverless/sql-databases/reference-content/known-differences.mdx

@@ -33,7 +33,7 @@ If you require strict compatibility with all PostgreSQL features, you can use [M
     NOTIFY channel, 'message';
     ```
 
-- Creating temporary tables or views is not supported.
+- It is not possible to create temporary tables or views.
 
     ```sql
     CREATE TEMPORARY TABLE table as {query};
@@ -50,7 +50,7 @@ If you require strict compatibility with all PostgreSQL features, you can use [M
     You can still refresh materialized views without the `CONCURRENTLY` option.
     </Message>
 
-- Declaring a cursor in transactions with `WITH HOLD` is not supported.
+- You can declare a cursor in transactions with `WITH HOLD`, but accurate cursor handling is not guaranteed, particularly when using multiple connections.
 
     ```sql
     BEGIN;
@@ -64,7 +64,7 @@ If you require strict compatibility with all PostgreSQL features, you can use [M
     CREATE SUBSCRIPTION subscription CONNECTION 'connection' PUBLICATION publication;
     ```
 
-- Preparing transactions is not supported.
+- It is not possible to prepare transactions.
 
     ```sql
     PREPARE TRANSACTION 'transactionid';
@@ -117,6 +117,14 @@ If you require strict compatibility with all PostgreSQL features, you can use [M
     SET TIME ZONE 'Europe/Paris';
     RESET timezone;
     ```
+    If you require these features to work consistently for a given SQL query, we suggest you set them in transactions:
+    ```sql
+    BEGIN;
+      SET TIME ZONE 'Europe/Paris';
+      SHOW timezone;
+    COMMIT;
+    ```
+    In this example, `SHOW timezone` will always display `Europe/Paris` without any impact from any other connection despite connection pooling.
 
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