Task: NL2SQL (source dataset: Spider)

Natural language to SQL, also known as NL2SQL, is the problem of generating a SQL query that can be executed on a input table, for a given natural language question.

You will be given an input table called "table" in the markdown format, as well as a question. Your task is to generate an SQL query that can be executed on the input table to answer the question.

Please ensure that the generated SQL only return relevant columns being specifically asked in the question (e.g., in SQL please don't return more than one columns in SELECT if only one column is needed to answer the given question, and similarly please refrain from using SELECT * unless the entire row is needed to answer the question).
 
When generating SQL code, please use the SQLite syntax to ensure that your SQL is executable on SQLite3. Use only columns that are present in the table, always use quotes around your column and table names (some column names have punctuation or special characters), and refer to the columns using the column-names exactly as they appear in the table, do not add or remove punctuation (underscore, slash, etc.)

No explanation, return the code only with the following markdown codeblock format : ```sql<SQL CODE>```. For example, ```sql
SELECT * FROM "table"
``` is a valid format.

Database:
book_1

Tables:

Table: Client
|   IdClient | Name           | Address            |            NumCC |
|-----------:|:---------------|:-------------------|-----------------:|
|          1 | James Smith    | Picadilly 2        | 1234567890123456 |
|          2 | Laura Jones    | Holland Park 13    | 1234567756953456 |
|          3 | Peter Doe      | High Street 42     | 1237596390123456 |
|          4 | Rose Johnson   | Notting Hill 46    | 4896357890123456 |
|          5 | Joseph Clinton | Leicester Square 1 | 1224569890123456 |
|          6 | Betty Fraser   | Whitehall 32       | 2444889890123456 |


Table: Orders
| IdOrder   |   IdClient | DateOrder   | DateExped   |
|:----------|-----------:|:------------|:------------|
| 0000001P  |          1 |             |             |
| 0000002P  |          1 |             |             |
| 0000003P  |          2 |             |             |
| 0000004P  |          4 |             |             |
| 0000005P  |          5 |             |             |
| 0000006P  |          3 |             |             |


Table: Author
|   idAuthor | Name                   |
|-----------:|:-----------------------|
|          1 | Jane Austin            |
|          2 | George Orwell          |
|          3 | J.R.R Tolkien          |
|          4 | Antoine de Saint-Exupy |
|          5 | Bram Stoker            |
|          6 | Plato                  |
|          7 | Vladimir Nabokov       |


Table: Book
|          ISBN | Title               |   Author |   PurchasePrice |   SalePrice |
|--------------:|:--------------------|---------:|----------------:|------------:|
| 8233771378567 | Pride and Prejudice |     2008 |            9.45 |       13.45 |
| 1235271378662 | 1984                |     2009 |           12.5  |       19.25 |
| 4554672899910 | The Hobbit          |     2002 |           19    |       33.15 |
| 5463467723747 | The Little Prince   |     2000 |           49    |       73.45 |
|  853477468299 | Dracula             |     2011 |            9.45 |       13.45 |
| 1243415243666 | The Republic        |     1997 |           10.45 |       15.75 |
|  482174555366 | Lolita              |     1998 |            4    |        9.45 |


Table: Author_Book
|        ISBN |   Author |
|------------:|---------:|
| 8.23377e+12 |        1 |
| 1.23527e+12 |        2 |
| 4.55467e+12 |        3 |
| 5.46347e+12 |        4 |
| 8.53477e+11 |        5 |
| 1.24342e+12 |        6 |
| 4.82175e+11 |        7 |


Table: Books_Order
|          ISBN | IdOrder   |   amount |
|--------------:|:----------|---------:|
| 8233771378567 | 0000001P  |        1 |
| 5463467723747 | 0000001P  |        2 |
|  482174555366 | 0000002P  |        1 |
| 4554672899910 | 0000003P  |        1 |
| 8233771378567 | 0000003P  |        1 |
| 1243415243666 | 0000003P  |        1 |
| 8233771378567 | 0000004P  |        1 |
| 4554672899910 | 0000005P  |        1 |
| 1243415243666 | 0000005P  |        1 |
| 5463467723747 | 0000005P  |        3 |


Question: What is the average sale price of books written by George Orwell?

db_id: book_1
tables: name: Client
data: Client.csv
name: Orders
data: Orders.csv
name: Author
data: Author.csv
name: Book
data: Book.csv
name: Author_Book
data: Author_Book.csv
name: Books_Order
data: Books_Order.csv
label: SELECT avg(saleprice) FROM Book AS T1 JOIN Author_book AS T2 ON T1.isbn  =  T2.isbn JOIN Author AS T3 ON T2.Author  =  T3.idAuthor WHERE T3.name  =  "George Orwell"
sqlite_path: $MMTU_HOME/data_sqlite/spider/spider_data/test_database/book_1/book_1.sqlite