This image presents a SQL interview question: **Question**: "Given two tables, find out the records which are not common in both?" **Tables:** | Table1 | Table2 | |--------|--------| | 10 | 10 | | 20 | 30 | | 30 | 50 | | 40 | | | 50 | | **Output required:** ``` ID 20 40 ``` (IDs present in Table1 but *not* in Table2.) **Approach:** The solution uses a **LEFT JOIN** to find records in Table1 that do not exist in Table2: ```sql SELECT a.id FROM table1 a LEFT JOIN table2 b ON a.id = b.id WHERE b.id IS NULL; ``` **Explanation:** - The `LEFT JOIN` returns all rows from Table1 and the matched rows from Table2. - If there is no match, the result is NULL from Table2. - `WHERE b.id IS NULL` filters out only those rows where there was no match, i.e., the IDs not present in Table2. **Diagram on the right:** It visually shows how the join works, producing NULLs where there is no match, which are then filtered in the output. **Summary:** This SQL technique helps in finding records present in one table but not the other, commonly referred to as "anti-join".