Add available bookings scripts and results

sql/table_is_free.sql

@@ -0,0 +1,17 @@
+-- available bookings - task 2
+-- changes:
+--   changed BookingDate (Reserved) data type from date to datetime, because I assumed that Little Lemon
+--   allows wants bookings per day and table - a table is considered blocked for 2 hours
+-- noqa: disable=CP03,LT02,RF03
+create function TableIsFree(Reserved datetime, TableNumber int)
+returns boolean
+deterministic
+begin
+    return (select not exists (
+        select BookingID
+        from Bookings as B
+        where
+            abs(timestampdiff(second, B.Reserved, Reserved)) < 2 * 60 * 60
+            and B.TableNumber = TableNumber
+    ));
+end