I am trying to make an INNER JOIN statement that will join two tables, the Orders table and the Customer table, these both share the value/key of CustomerID. The Customer table has the information for which state a customer lives in. The Orders table has the information for which customer, according to their customer ID, bought which product. I need to find which products are the top 3 most popular in certain states. Please find the table descriptions images below, so you can understand what I mean.
Orders table:
Customer table:
How can I make this INNER JOIN statement and include the logical operators (and/or) to make this happen?
Thanks!
Try this,
SELECT column_name(s)
FROM Customer
INNER JOIN Order
ON Customer.CustomerID= Order.Customer_ID AND <conditions>;
Inner Join is just only 1 way of joining 2 tables. You can also join these two tables using WHERE closure as follows,
SELECT column_name(s)
FROM Customer c, Order o
WHERE c.CustomerID = o.Customer_ID AND <condition>
Related
I believe I have formed this question title correctly because I wasn't sure how to form it. As an example, I have summarized my query below.
I have an order table which saves order details like customer id, address and product ids and quantity ordered for each order in a row. So multiple inventory/product ids are saved in a single row.
so my query looks like: this is a summarized query for an easier explanation I have omitted various other fields.
SELECT customer.name,customer.address,tbl_order.order_date,tbl_order.product1_id,tbl_order.product2_id,inventory.product1_name,inventory.product2_name
FROM tbl_order
INNER JOIN customer ON tbl_order.customer_id = customer.id
INNER JOIN inventory on tbl_order.product1_id = inventory.id
INNER JOIN inventory on tbl_order.product2_id = inventory.id
where YEAR(tbl_order.order_date)='$year'
So my question is how to get the inventory details from the inventory table based on each product id from tbl_order. I am running a while loop to show all data for a year
while($row=mysqli_fetch_assoc($sql1))
I can divide this query into 2 and run the inventory query individually but then how to combine the while loop, as sometimes there could also be empty query when some products are not in order table (depending on order to order, not all products are ordered) so this doesn't work
while($row=mysqli_fetch_assoc($sql1)) and ($row1=mysqli_fetch_assoc($inv1)) and ($row2=mysqli_fetch_assoc($inv2))
and so one for 10 products
First, of all you have bad DB design and I kindly advice to normalize your DB.
Second, if you can not re-design the DB you can use multiple joins with aliases like:
SELECT
customer.name, customer.address, tbl_order.order_date,
tbl_order.product1_id, inv1.product1_name,
tbl_order.product2_id, inv2.product2_name
FROM tbl_order
INNER JOIN customer ON tbl_order.customer_id = customer.id
INNER JOIN inventory AS inv1 ON tbl_order.product1_id = inv1.id
INNER JOIN inventory AS inv2 ON tbl_order.product2_id = inv2.id
WHERE YEAR(tbl_order.order_date)='$year'
My database has 3 tables. One is called Customer, one is called Orders, and one is called RMA. The RMA table has the info regarding returns. I'll include a screen shot of all 3 so you can see the appropriate attributes. This is the code of the query I'm working on:
SELECT State, SKU, count(*)
from Orders INNER JOIN Customer ON Orders.Customer_ID = Customer.CustomerID
INNER JOIN RMA ON Orders.Order_ID = RMA.Reason
Group by SKU
Order by SKU
LIMIT 10;
I'm trying to get how much of each product(SKU) is returned in each state(State). Any help would really be appreciated. I'm not sure why, but anytime I include a JOIN statement, my query takes anywhere from 5 minutes to 20 minutes to process.
[ Customer table]
!2[ RMA table]
!3
Your query should look like this:
SELECT c.State, o.SKU, COUNT(*)
FROM Orders o INNER JOIN
Customer c
ON o.Customer_ID = c.CustomerID JOIN
RMA
ON o.Order_ID = RMA.Order_Id
GROUP BY c.State, o.SKU
ORDER BY SKU;
Your issue is probably the incorrect JOIN condition between Orders and RMA.
If you have primary keys properly declared on the tables, then this query should have good-enough performance.
Given you are joining with an Orders table I'm going to assume this table contains all the orders that the company has ever done. This can be quite large and would likely cause the slowness you are seeing.
You can likely improve this query if you place some constraint on the Orders you are selecting, restricting what date range you use is common way to do this. If you provide more information about what the query is for and how large the dataset is everyone will be able to provide better guidance as to what filters would work best.
Consider the following query i tried, there two tables, Orders and Customers, each have column name CustomerID, when i try to display both CustomerID's only one column is displaying, i can't understand why is it so, or am i understanding the basics wrong.
SELECT Customers.CustomerID,Orders.CustomerID
FROM customers
inner JOIN orders
on customers.customerid=orders.customerid;
When i try to display only one column it is displaying well and good
SELECT Customers.CustomerID
FROM customers
inner JOIN orders
on customers.customerid=orders.customerid;
and
SELECT Customers.CustomerID
FROM customers
inner JOIN orders
on customers.customerid=orders.customerid;
So my problem is why I cant display the both.
use alias
SELECT Customers.CustomerID as customerid,Orders.CustomerID as ocustomerid
FROM customers
inner JOIN orders
on customers.customerid=orders.customerid;
You need to define an alias for each column:
SELECT Customers.CustomerID as customer_id, Orders.CustomerID as order_id
FROM customers
inner JOIN orders
on customers.customerid=orders.customerid;
This is a peculiarity of some query interfaces. Your first query (which I would write like this) is:
SELECT c.CustomerID, o.CustomerID
FROM customers c INNER JOIN
orders o
ON c.customerid = o.customerid;
This returns two columns, both named CustomerId. Some query interfaces insist that the resulting columns be unique in the result set. Hence, the results ignore "subsequent" columns with the same name.
You can get a flavor of this by using the query as a subquery:
SELECT x.*
FROM (SELECT c.CustomerID, o.CustomerID
FROM customers c INNER JOIN
orders o
ON c.customerid = o.customerid
) x;
This should return an error, because CustomerId is ill-defined.
Three points to remember:
Most databases and query interfaces allow result sets with multiple columns with the same name.
No database allows multiple columns with the same name in a subquery.
You know how to fix this by assigning a column alias, which is a best-practice anyway.
It's been so long since I did any Mysql queries I forgot how to do basic joins. I have two tables:
Orders_ and
Members
I need to create one view which displays all the orders with the associated Email and Member_Id.
http://i.imgur.com/7ttXtrk.png <-- Tables
The query, based on your image, should look like so:
SELECT Orders.*, Members.*
FROM Orders
INNER JOIN Members ON Orders.coordinateList_Id = Members.Members_Member`
I would refer to the MySQL reference
SELECT *
FROM Orders
INNER JOIN Members
ON Orders.coordinateList_Id = Members.Members_Member
I have to get data from two SQL tables but I am unsure of what join to use and the same tables have the same customers_id table would I use an inner join?
table - customers
customers_id
customers_firstname
customers_lastname
customers_email_address
table - orders
customers_id
customers_street_address
customers_suburb
customers_city
customers_postcode
customers_state
customers_country
It depends on what results you want. If you want every record in Customers regardless of whether there is a matching record in orders the you would use an LEFT OUTER JOIN. If not you would use an INNER JOIN. This is the article I typically refer people to for a basic explanation of joins.
An INNER JOIN would look like this:
SELECT c.customers_id,
c.customers_firstname,
c.customers_lastname,
o.customers_street_address,
o.customers_city,
o.customers_postcode,
o.customers_state
FROM customers as c
INNER JOIN orders as o
ON c.customers_id = o.customers_id
I purposely did not do select *. Try to get into the habit of only selecting the columns you want from tables instead of everything.
The join you should use depends on which information you are trying to retain, based on the customer ID. If you're looking to retain all of the information from customers even if there is no match with orders you would use a left join. Conversely, if you wanted to retain all the information from orders even if there were no match with customers you would use a right join.
If you want to return all of the information, and combine rows which have a match, use a full join. Finally, you can use an inner join if you only want the rows which have a match from either table.
the same tables have the same customers_id table
I think you meant to say they have a common column, being customers_id, in which case you can use NATURAL JOIN.
INNER JOIN Ya you can use it.
You can write below query to get your all data from two tables.I am going to write full join query for you.y
select customers.customers_firstname,
customers.customer_lastname,
orders.customers_city
from customers
INNER JOIN orders
ON customer.customers_id = orders.customers_id