SQL Query Using AND OR - sql

Question

I have two tables: Customers and Orders.
I need to know which Customers have ordered "Bread" AND (Milk or Ice Cream) in a given month.
How should I write the SQL query?
Thanks.

Answer 1

As others have said in the comments, you should really try to improve your question so that people are more inclined to answer and help you.
Setting up some test data (making assumptions about your schema):
CREATE TABLE Customers (
CustomerID INT,
CustomerName VARCHAR(50)
)
CREATE TABLE Orders (
OrderId INT,
OrderDate DATETIME,
CustomerID INT,
Product VARCHAR(50)
)
INSERT INTO Customers
SELECT 1, 'John Smith'
UNION
SELECT 2, 'Jane Doe'
UNION
SELECT 3, 'Rachel Booth'
UNION
SELECT 4, 'Steve Barnes'
UNION
SELECT 5, 'Nancy Green'
UNION
SELECT 6, 'Phil Jones'
INSERT INTO Orders
SELECT 1, '2016-09-01', 1, 'Bread'
UNION
SELECT 2, '2016-09-10', 3, 'Milk'
UNION
SELECT 3, '2016-09-19', 1, 'Milk'
UNION
SELECT 4, '2016-10-07', 4, 'Bread'
UNION
SELECT 5, '2016-10-13', 2, 'Milk'
UNION
SELECT 6, '2016-10-15', 4, 'Milk'
UNION
SELECT 7, '2016-10-19', 6, 'Milk'
UNION
SELECT 8, '2016-10-21', 6, 'Ice Cream'
UNION
SELECT 9, '2016-10-27', 1, 'Milk'
UNION
SELECT 10, '2016-10-28', 4, 'Milk'
UNION
SELECT 11, '2016-11-06', 5, 'Ice Cream'
UNION
SELECT 12, '2016-11-09', 5, 'Bread'
And setting the desired month to check:
DECLARE #Month DATETIME
SET #Month = '2016-09-01'
I would get a list of Customers fitting your logic like this:
SELECT DISTINCT c.CustomerName
FROM Customers c
JOIN Orders ob ON ob.CustomerID = c.CustomerID
JOIN Orders omi ON omi.CustomerID = c.CustomerID
WHERE ob.Product = 'Bread'
AND omi.Product IN ('Milk','Ice Cream')
AND DATEADD(month, DATEDIFF(month, 0, ob.OrderDate), 0) = DATEADD(month, DATEDIFF(month, 0, omi.OrderDate), 0)
AND DATEADD(month, DATEDIFF(month, 0, ob.OrderDate), 0) = #Month