Add temporal validation challenge

src/data/courses/sql/chapters/data-definition-language/lessons/temporal-validation.md

@@ -0,0 +1,33 @@
+---
+title: Temporal Validation
+description: Create a table for event scheduling with temporal constraints
+order: 330
+type: challenge
+initSteps: []
+expectedResults:
+  - columns: [message]
+    values:
+      - ['Table created successfully']
+---
+
+You need to create a table named `events` for events hosted at the bookstore. The table should track event information using appropriate data types and constraints listed below.
+
+| Column     | Data Type      | Constraints                                                            |
+| ---------- | -------------- | ---------------------------------------------------------------------- |
+| id         | `INTEGER`      | Primary Key                                                            |
+| title      | `VARCHAR(100)` | Null values not allowed                                                |
+| start_time | `TIMESTAMP`    | Null values not allowed. Also ensure `start_time` is always in future. |
+| end_time   | `TIMESTAMP`    | Null values not allowed. Also ensure `end_time` is after `start_time`  |
+| created_at | `TIMESTAMP`    | Not null and default `CURRENT_TIMESTAMP`                               |
+
+Please note that you are being tested for your ability to work with temporal data. Make sure to add the following `CHECK` constraints apart from the other constraints mentioned in the table:
+
+- `start_time` must be in the future
+- `end_time` must be after `start_time`
+- `created_at` must default to `CURRENT_TIMESTAMP`
+
+> Also, please note that we are using PostgreSQL for our editor, so make sure to use the appropriate statements.
+
+## Expected Output
+
+After executing your query, the table should be created successfully with all specified columns and constraints.