Add functionality to support custom sql query using with select format

- Add functionality to support custom sql query using `with select` format
- Add unit test
- Fixes GH-2753

src/DocumentDbTests/Reading/query_by_sql.cs

@@ -379,4 +379,23 @@ public async Task get_count_asynchronously()
         var sum = sumResults.Single();
         sum.ShouldBe(4);
     }
+
+    [Fact]
+    public async Task can_query_using_with_select()
+    {
+        await using var session = theStore.LightweightSession();
+        var time = DateTimeOffset.UtcNow;
+        var u = new User { FirstName = "Jeremy", LastName = "Miller", ModifiedAt = time, Age = 28 };
+        session.Store(u);
+        await session.SaveChangesAsync();
+
+        var users =
+            await
+                session.QueryAsync<User>(
+                    "with my_with_query as (select data from mt_doc_user where data ->> 'FirstName' = 'Jeremy') select data from my_with_query");
+        var user = users.Single();
+
+        user.LastName.ShouldBe("Miller");
+        user.Id.ShouldBe(u.Id);
+    }
 }

src/Marten/Linq/QueryHandlers/UserSuppliedQueryHandler.cs

@@ -26,7 +26,8 @@ public UserSuppliedQueryHandler(IMartenSession session, string sql, object[] par
     {
         _sql = sql.TrimStart();
         _parameters = parameters;
-        SqlContainsCustomSelect = _sql.StartsWith("select", StringComparison.OrdinalIgnoreCase);
+        SqlContainsCustomSelect = _sql.StartsWith("select", StringComparison.OrdinalIgnoreCase)
+                                  || IsWithFollowedBySelect(_sql);
 
         _selectClause = GetSelectClause(session);
         _selector = (ISelector<T>)_selectClause.BuildSelector(session);
@@ -136,4 +137,39 @@ private ISelectClause GetSelectClause(IMartenSession session)
 
         return session.StorageFor(typeof(T));
     }
+
+    private static bool IsWithFollowedBySelect(string sql)
+    {
+        var parenthesesLevel = 0;
+        var isWithBlockDetected = false;
+
+         for (var i = 0; i < sql.Length; i++)
+         {
+             var c = sql[i];
+
+            // Check for parentheses to handle nested structures
+            if (c == '(')
+            {
+                parenthesesLevel++;
+            }
+            else if (c == ')')
+            {
+                parenthesesLevel--;
+            }
+
+            // Detect the beginning of the WITH block
+            if (!isWithBlockDetected && i < sql.Length - 4 && sql.Substring(i, 4).Equals("with", StringComparison.OrdinalIgnoreCase))
+            {
+                isWithBlockDetected = true;
+            }
+
+            // Detect the beginning of the SELECT block only if WITH block is detected and at top-level
+            if (isWithBlockDetected && i < sql.Length - 6 && sql.Substring(i, 6).Equals("select", StringComparison.OrdinalIgnoreCase) && parenthesesLevel == 0)
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
 }