Sql Questions

1. Group by /having
2. Union and union all
3. Query order
	Getting Data (FROM/JOIN)
	Row Filter (WHERE)
	Grouping (GROUP BY)
	Group Filter (HAVING)
	Return Expression (SELECT)
	Order & Paging (ORDER BY & LIMIT/OFFSET)
4. cte


5.How to find the last id in a table?
6.How to find the values in a text column of a table that start with a certain letter? LIKE 'A%';
7.What is normalization in SQL, and why use it?

8.How to find a duplicate record?

9.Given a table TBL with a field Nmbr that has rows with the following values:

	1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1

	Write a query to add 2 where Nmbr is 0 and add 3 where Nmbr is 1.

10.
	test_a
  (10),
  (20),
  (30),
  (40),
  (50);

	test_b
  (10),
  (30),
  (50);

	Output
	20
	40

11.

	Given the following tables:

sql> SELECT * FROM runners;
+----+--------------+
| id | name         |
+----+--------------+
|  1 | John Doe     |
|  2 | Jane Doe     |
|  3 | Alice Jones  |
|  4 | Bobby Louis  |
|  5 | Lisa Romero  |
+----+--------------+

sql> SELECT * FROM races;
+----+----------------+-----------+
| id | event          | winner_id |
+----+----------------+-----------+
|  1 | 100 meter dash |  2        |
|  2 | 500 meter dash |  3        |
|  3 | cross-country  |  2        |
|  4 | triathalon     |  NULL     |
+----+----------------+-----------+
What will be the result of the query below?

SELECT * FROM runners WHERE id NOT IN (SELECT winner_id FROM races)