Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Customers_Policies ( Customer_ID INTEGER, Policy_ID INTEGER, Date_Opened DATE, Date_Closed DATE )
TABLE: CREATE TABLE Settlements ( Settlement_ID INTEGER, Claim_ID INTEGER, Effective_Date DATE, Settlement_Amount REAL )
TABLE: CREATE TABLE Customers ( Customer_ID INTEGER, Customer_name VARCHAR(40) )
TABLE: CREATE TABLE First_Notification_of_Loss ( FNOL_ID INTEGER, Customer_ID INTEGER, Policy_ID INTEGER, Service_ID INTEGER )
TABLE: CREATE TABLE Claims ( Claim_ID INTEGER, FNOL_ID INTEGER, Effective_Date DATE )
TABLE: CREATE TABLE Services ( Service_ID INTEGER, Service_name VARCHAR(40) )
TABLE: CREATE TABLE Available_Policies ( Policy_ID INTEGER, policy_type_code CHAR(15), Customer_Phone VARCHAR(255) )

### Question ###
Retrieve the open dates of all the policies associated with the customer whose name contains 'Diana', bin the open dates into the day of week interval and count them for a bar chart.

### Accurate SQL ###

SELECT Date_Opened, COUNT(Date_Opened) FROM Customers AS t1 JOIN Customers_Policies AS t2 ON t1.Customer_ID = t2.Customer_ID WHERE t1.Customer_name LIKE "%Diana%"