I am having to set up a query that retrieves the last comment made on a customer, if no one has commented on them for more than 4 weeks. I can make it work using the query below, but for some reason the comment column won't display the latest record. Instead it displays the oldest, however the date shows the newest. It may just be because I'm a noob at SQL, but what exactly am I doing wrong here?
SELECT DISTINCT
customerid, id, customername, user, MAX(date) AS 'maxdate', comment
FROM comments
WHERE customerid IN
(SELECT DISTINCT id FROM customers WHERE pastdue='1' AND hubarea='1')
AND customerid NOT IN
(SELECT DISTINCT customerid FROM comments WHERE DATEDIFF(NOW(), date) <= 27)
GROUP BY customerid
ORDER BY maxdate
The first "WHERE" clause is just ensuring that it shows only customers from a specific area, and that they are "past due enabled". The second makes sure that the customer has not been commented on within the last 27 days. It's grouped by customerid, because that is the number that is associated with each individual customer. When I get the results, everything is right except for the comment column...any ideas?
Join much better to nested query so you use the join instead of nested query
Join increase your speed
this query resolve your problem.
SELECT DISTINCT
customerid,id, customername, user, MAX(date) AS 'maxdate', comment
FROM comments inner join customers on comments.customerid = customers.id
WHERE comments.pastdue='1' AND comments.hubarea='1' AND DATEDIFF(NOW(), comments.date) <= 27
GROUP BY customerid
ORDER BY maxdate
I think this might probably do what you are trying to achieve. If you can execute it and maybe report back if it does or not, i can probably tweak it if needed. Logically, it ' should' work - IF i have understood ur problem correctly :)
SELECT X.customerid, X.maxdate, co.id, c.customername, co.user, co.comment
FROM
(SELECT customerid, MAX(date) AS 'maxdate'
FROM comments cm
INNER JOIN customers cu ON cu.id = cm.customerid
WHERE cu.pastdue='1'
AND cu.hubarea='1'
AND DATEDIFF(NOW(), cm.date) <= 27)
GROUP BY customerid) X
INNER JOIN comments co ON X.customerid = co.customerid and X.maxdate = co.date
INNER JOIN customer c ON X.customerid = c.id
ORDER BY X.maxdate
You need to have subquery for each case.
SELECT a.*
FROM comments a
INNER JOIN
(
SELECT customerID, max(`date`) maxDate
FROM comments
GROUP BY customerID
) b ON a.customerID = b.customerID AND
a.`date` = b.maxDate
INNER JOIN
(
SELECT DISTINCT ID
FROM customers
WHERE pastdue = 1 AND hubarea = 1
) c ON c.ID = a.customerID
LEFT JOIN
(
SELECT DISTINCT customerid
FROM comments
WHERE DATEDIFF(NOW(), date) <= 27
) d ON a.customerID = d.customerID
WHERE d.customerID IS NULL
The first join gets the latest record for each customer.
The second join shows only customers from a specific area, and that they are "past due enabled".
The third join, which uses LEFT JOIN, select all customers that has not been commented on within the last 27 days. In this case,only records without on the list are selected because of the condition d.customerID IS NULL.
But tomake your query shorter, if the customers table has already unique records for customer, then you don't need to have subquery on it.Directly join the table and put the condition on the WHERE clause.
SELECT a.*
FROM comments a
INNER JOIN
(
SELECT customerID, max(`date`) maxDate
FROM comments
GROUP BY customerID
) b ON a.customerID = b.customerID AND
a.`date` = b.maxDate
INNER JOIN customers c
ON c.ID = a.customerID
LEFT JOIN
(
SELECT DISTINCT customerid
FROM comments
WHERE DATEDIFF(NOW(), date) <= 27
) d ON a.customerID = d.customerID
WHERE d.customerID IS NULL AND
c.pastdue = 1 AND
c.hubarea = 1
Two of your table columns are not contained in either an aggregate function or the GROUP BY clause. for example suppose that you have two data rows with the same customer id and same date, but with different comment data. how SQL should aggregate these two rows? :( it will generate an error...
try this
select customerid, id, customername, user,date, comment from(
select customerid, id, customername, user,date, comment,
#rank := IF(#current_customer = id, #rank+ 1, 1),
#current_customer := id
from comments
where customerid IN
(SELECT DISTINCT id FROM customers WHERE pastdue='1' AND hubarea='1')
AND customerid NOT IN
(SELECT DISTINCT customerid FROM comments WHERE DATEDIFF(NOW(), date) <= 27)
order by customerid, maxdate desc
) where rank <= 1
Related
Here's my orders table:
I want to select all orders excluding very first order of each customer (if customer has placed multiple orders).
So if a customer e.g. 215 has total 8 orders, then I will select his all last 7 orders excluding his very first order 70000 which was placed on 10 July 2017.
But if a customer e.g. 219 had placed only one order 70007, it must be selected by the query.
Using an anti-join approach:
SELECT o1.order_id, o1.customer_id, o1.order_date, o1.order_value
FROM orders o1
LEFT JOIN
(
SELECT customer_id, MIN(order_date) AS min_order_date, COUNT(*) AS cnt
FROM orders
GROUP BY customer_id
) o2
ON o1.customer_id = o2.customer_id AND
o1.order_date = o2.min_order_date
WHERE
o2.customer_site = 1 AND
(o2.customer_id IS NULL OR
o2.cnt = 1);
The idea here is to try to match each record in orders to a record in the subquery, which contains only first order records, for each customer. If we can't find a match, then such an order record cannot be the first.
You can try below -
select order_id,customer_id,order_date,order_Value
from tablename
group by order_id,customer_id,order_date,order_Value
having count(order_id)=1
union all
select order_id,customer_id,order_date,order_Value
from tablename a where order_date not in (select min(order_date) from tablename b
where a.customer_id=b.customer_id)
Solution
Dear #Tim Biegeleisen, your answer almost done. just add HAVING COUNT(customer_id)>1
So the query is below:
SELECT o1.order_id, o1.customer_id, o1.order_date, o1.order_value
FROM orders o1
LEFT JOIN (
SELECT customer_id, MIN(order_date) AS min_order_date
FROM orders
GROUP BY customer_id
HAVING COUNT(customer_id)>1
) o2
ON o1.customer_id = o2.customer_id AND
o1.order_date = o2.min_order_date
WHERE
o2.customer_id IS NULL;
I try to obtain a list of all customers my company has not had any assignments for in the last year.
SELECT MAX(assignment_date), full_name
FROM assignments
CROSS JOIN customers
WHERE assignments.customer_id = customers.id
AND assignment_date < '2017-01-01' -- Dynamic value from backend
GROUP BY full_name
ORDER BY assignment_date DESC
This does not seem to work as intended however, since it only returns some customers we did have assignments for in that timeframe. How would I go about implementing such a feature?
Try this code:
SELECT MAX(assignment_date), full_name
FROM customers
where id not in (SELECT id FROM customers inner join assigments on customers.id = assignments.customer_id WHERE assignment_date > '2017-01-01' )
This will return all customers in your database and remove all of them who did have assigments in last year. You should get all customers without assigments before '2017-01-01' as a result
left join customers to assignments where assignments.customer_id IS NULL
and assignment_date greater than '2017-01-01' i.e.
SELECT MAX(assignment_date), full_name
FROM assignments
WHERE assignments.customer_id IN
(SELECT customers.id
FROM customers
LEFT JOIN assignments ON assignments.customer_id = customers.id
WHERE assignments.customer_id IS NULL
AND assignment_date > '2017-01-01')
GROUP BY full_name
ORDER BY assignment_date DESC
I would suggest left join, group by and having:
SELECT MAX(assignment_date), full_name
FROM customers c LEFT JOIN
assignments a
ON a.customer_id = c.id
GROUP BY c.full_name
HAVING MAX(a.assignment_date) < '2017-01-01' OR
MAX(a.assignment_date) IS NULL
ORDER BY MAX(assignment_date) DESC;
It seems you want to show all customers with their last assignment date, but you want to restrict that list to customers that had no assignment since 2017-01-01. This means the dates you will be showing will be null for those customers who had never had an assignment and a date before 2017-01-01 for the others.
So outer join the last dates to the customers and only keep the rows where that date is before 2017-01-01 or null:
select c.full_name, a.max_date
from customers c
left join
(
select customer_id, max(assignment_date) as max_date
from assignments
group by customer_id
) a on a.customer_id = c.customer_id
where a.max_date < date '2017-01-01'
or a.max_date is null
order by a.max_date desc;
I want each student's name, last payment date only. means only day.
I know i won't help you at all giving this code:
But you could try to learn something from it.
SELECT S.Id, S.Name, F.max_date, F.FeeAmt
FROM tbl_student As S
INNER JOIN (
SELECT t.Id, MAX(t.Date) As max_date, t.FeeAmt FROM tbl_fees As t GROUP BY t.Id
) As F ON F.Id=S.Id
First we selected all users from tbl_student, and then we are joining fees, selecting max date and grouping by user. The result is last (date) fee per user.
Please try this query. I hope this should give you the expected output:
SELECT S.Name, T1.LastPaymentDate
FROM
(SELECT Id, Max([Date]) AS LastPaymentDate from tbl_fees GROUP BY Id) AS T1
INNER JOIN
tbl_student AS S
ON T1.Id = S.Id
SELECT S.name,SUB.LAST_DATE
FROM tbl_student S
JOIN (SELECT f.id AS ID,MAX(f.Date) AS LAST_DATE
FROM tbl_fees f
GROUP BY f.id) SUB
ON SUB.id = S.id
I have the following query which works perfectly, but only if each select finds a row.
I've attempted to add IFNULL to return 0 if no rows were found but I'm still not getting the correct return.
SELECT IFNULL(paid_value,0)-IFNULL(ordered_value,0)+IFNULL(credit_value,0) AS account_balance
FROM
(
SELECT customer_id, SUM(order_total) AS ordered_value
FROM orders
WHERE customer_id = '1'
GROUP BY customer_id
) AS orders
LEFT JOIN
(
SELECT customer_id, SUM(amount) AS paid_value
FROM transactions
WHERE customer_id = '1'
GROUP BY customer_id
) as payments
ON orders.customer_id = payments.customer_id
LEFT JOIN
(
SELECT customer_id, SUM(amount) AS credit_value
FROM credits
WHERE customer_id = '1'
GROUP BY customer_id
) as credits
ON orders.customer_id = credits.customer_id
This query currently returns empty, it's not returning NULL or 0.
When I run
SELECT customer_id, SUM(order_total) AS ordered_value
FROM orders
WHERE customer_id = '1'
GROUP BY customer_id
It also returns empty, not NULL or 0, unless there's a row. In order for the full query to work, each of the 3 separate queries need to have a row in them.
Any ideas?
It if because none of the columns have a result set, so an empty result set is returned, if you want to always display a row in any case you can try with some tricks like this one for example :
SELECT IFNULL(SUM(payments.paid_value),0)-IFNULL(SUM(orders .ordered_value),0)+IFNULL(SUM(credits.credit_value),0) AS account_balance
FROM
(SELECT 1 AS idx, 0 AS paid_value, 0 AS ordered_value, 0 AS credit_value) a
LEFT JOIN
(
SELECT 1 AS idx, customer_id, SUM(order_total) AS ordered_value
FROM orders
WHERE customer_id = '1'
GROUP BY customer_id
) AS orders
ON a.idx = orders.idx
LEFT JOIN
(
SELECT customer_id, SUM(amount) AS paid_value
FROM transactions
WHERE customer_id = '1'
GROUP BY customer_id
) as payments
ON orders.customer_id = payments.customer_id
LEFT JOIN
(
SELECT customer_id, SUM(amount) AS credit_value
FROM credits
WHERE customer_id = '1'
GROUP BY customer_id
) as credits
ON orders.customer_id = credits.customer_id
GROUP BY a.idx
The example is a proof of concept that can be adapted even to other situations where you need to always returns a row with default values even with no elements in underlying tables .
If you want row event if there is no data available, then I suppose you should either have UNION. Or In this scenario you can include you Customer Table & put each Table on Right Side, make a LEFT JOIN.
I think following select will give you an IDEA.
SELECT O.customer_id, SUM(O.order_total) AS ordered_value
FROM Customers C
left join orders O on C.ID =o.customer_id
WHERE O.customer_id = '1'
GROUP BY O.customer_id
I need help writing a MySQL query. So far, none of the questions out there seem to fit my needs.
I have an order table and an order_log table. In the order_log table I make a record every time an order's status is changed. I need to display a list of the most recent status changes from the order_log table. The query I'm currently using does a JOIN on the two tables and grabs everything where order.status = order_log.status.
The problem with this is that some times an order will pass through the same status more than once. When that occurs, my query grabs every entry in the order_log table for that order and that status, but I only want the most recent log.
I tried writing a new JOIN query to grab the Max of the order_log date entry, but it's only returning 1 entry. This is what I have.
SELECT *
FROM order_status_log AS l
JOIN orders AS o ON ( l.order_id = o.id )
WHERE l.status = o.status
AND l.date = (
SELECT MAX( date )
FROM order_status_log l2
JOIN orders AS o2 ON ( l2.order_id = o2.id )
)
Any ideas?
there are many ways to do it, one is to have a separate subquery the gets the latest entry of each record: order_ID.
The result of the subquery is then joined back with the original table but has multiple conditions: that it matches the order_ID and also the latest date.
SELECT a.*, b.*
FROM `order` a
INNER JOIN order_log b
ON a.id = b.order_ID
INNER JOIN
(
SELECT order_ID, MAX(date) max_date
FROM order_log
GROUP BY order_ID
) c on b.order_ID = c.order_ID AND
b.date = c.max_date
That may help;
select olg.column1,o.column2,max(olg.date) from --You can add other columns as well
order_status_log olg
join orders o
on olg.id = o.order_id
group by olg.column1,o.column2