In this task you are expected to fix an SQL query based on feedback. You will be given an SQL statement and an English description with what is wrong about that SQL statement. You must correct the SQL statement based off of the feedback. An SQL query works by selecting data from a table where certain conditions apply. A table contains columns where every row in that table must have a value for each column. Every table has a primary key that uniquely identifies each row, usually an id. To choose which columns are returned you specify that after the "SELECT" statement. Next, you use a "FROM" statement to specify what tables you want to select the data from. When you specify a table you can rename it with the "AS" statement. You can reference that table by whatever name follows the "AS" statement. If you want to select data from multiple tables you need to use the "JOIN" statement. This will join the tables together by pairing a row in one table with every row in the other table (Cartesian Product). To limit the number of rows returned you should use the "ON" statement. This will only return rows where the condition specified after the statement is true, this is usually an equals operator with primary keys. You can also use the "WHERE" statement to specify that only rows with column values statisfying a certain condition, should be returned. The "GROUP BY" statement will group rows together that have equal column values for whatever columns follows the statement. The "HAVING" statement will return groups that statisfy whatever condition follows the statement. Any column(s) being returned from grouped rows must either be an aggregate function, (AVG, MAX, COUNT, SUM, ...) of a column, or the column(s) that the data was grouped by. To sort the returned data you can use the "ORDER BY" command which will order the data by whatever aggregate function or column follows the statement. The "DESC" statement will sort in descending order and the "ASC" statement will sort in ascending order. Finally, you can use the "LIMIT" statement to return a certain number of rows. When "*" is used in an SQL statement every column is returned. For example, SELECT * FROM table WHERE attribute = 1, will select every column from rows with the attribute column equal to 1. 

SQL: SELECT Customer_Name FROM Clients EXCEPT SELECT Customer_Name FROM Clients
Feedback: In step 2 , make sure customers have bookings .
SELECT Customer_Name FROM Clients EXCEPT SELECT T2.Customer_Name FROM Bookings AS T1 JOIN Clients AS T2 ON T1.Customer_ID  =  T2.Client_ID

SQL: SELECT T2.Name FROM museum AS T1 JOIN visitor AS T2 JOIN visit AS T3 ON T1.Museum_ID = T3.Museum_ID AND T3.visitor_ID = T2.ID WHERE T1.Open_Year > 2009 INTERSECT SELECT T2.Name FROM museum AS T1 JOIN visitor AS T2 JOIN visit AS T3 ON T1.Museum_ID = T3.Museum_ID AND T3.visitor_ID = T2.ID WHERE T1.Open_Year < 2011
Feedback: Ensure that open year less than 2009 in step 2 , Make sure open year greater than 2011 in step 3.
SELECT t1.name FROM visitor AS t1 JOIN visit AS t2 ON t1.id  =  t2.visitor_id JOIN museum AS t3 ON t3.Museum_ID  =  t2.Museum_ID WHERE t3.open_year  <  2009 INTERSECT SELECT t1.name FROM visitor AS t1 JOIN visit AS t2 ON t1.id  =  t2.visitor_id JOIN museum AS t3 ON t3.Museum_ID  =  t2.Museum_ID WHERE t3.open_year  >  2011

SQL: SELECT dimensions FROM product GROUP BY dimensions HAVING Count ( * ) > 3
Feedback: Replace dimensions with product in step 1.

SELECT max_page_size FROM product GROUP BY max_page_size HAVING count(*)  >  3