Ok, I have a slightly complicated MySQL query
SELECT
childcare_attendance.supplier_id,
suppliers.name As `Childcare Provider`,
Count(families.ufi) As Attended,
families.ufi
FROM
childcare_attendance
LEFT OUTER JOIN
suppliers ON suppliers.id = childcare_attendance.supplier_id
LEFT OUTER JOIN
clients ON childcare_attendance.client_id = clients.id
LEFT OUTER JOIN
families ON clients.family_id = families.id
WHERE
childcare_attendance.trashed <> 1
GROUP BY
childcare_attendance.supplier_id, families.ufi
My issue is I want to create a report that lists the number of unique families that are attending each of the childcare places. I assumed that the above query would perform the task, although the childcare providers are showing multiple times and I am unsure why.
EDIT
Here is a SQL Fiddle without data (I will work on getting some test data in there)
http://sqlfiddle.com/#!9/7ef8e8
Related
I have three tables, tblPresents, tblPresentsOrdered and tblPresentsDelivered.
What I want to do is sum up all the orders and deliveries for a given present ID, so I can tally up the total ordered and delivered and check for discrepancies.
So far I have the following:
$sql ='SELECT prsName, SUM(ordQuantity) AS qtyOrdered,
SUM(delQuantity) AS qtyDelivered
FROM tblPresentOrders
LEFT JOIN tblPresentDeliveries
ON tblPresentDeliveries.delPresent = tblPresentOrders.ordPresent
RIGHT JOIN tblPresents ON tblPresents.prsID = tblPresentOrders.ordPresent
GROUP BY prsName';
The first column (Ordered) is summing up correctly, but the deliveries is counting the delivery twice (there are two separate orders for that line).
What am I doing wrong?
Because you can have multiple orders per delivery (and presumably multiple presents per order) you need to perform aggregation in derived tables before JOINing to avoid duplication in counted/summed values. Note that using a mixture of LEFT JOIN and RIGHT JOIN in the same query can be a bit hard to read so I've rewritten the query using only LEFT JOINs.
SELECT p.prsName, o.qtyOrdered, d.qtyDelivered
FROM tblPresents p
LEFT JOIN (SELECT ordPresent, SUM(ordQuantity) AS qtyOrdered
FROM tblPresentOrders
GROUP BY ordPresent) o ON o.ordPresent = p.prsID
LEFT JOIN (SELECT delPresent, SUM(delQuantity) AS qtyDelivered
FROM tblPresentDeliveries
GROUP BY delPresent) d ON d.delPresent = p.prsID
I am working with four tables:
query,
store,
cluster_group,
tv_region
I want to retrieve query records belonging to a particular TV Region record.
A query record either belongs to a record in the store or cluster_group tables. The query table has 'store_id' and 'cluster_group_id' columns. Either will be null whilst the other will refer to a record in the store or cluster_group table. The store and cluster_group tables both have a 'tv_region_id' column.
To retrieve query records that belong to a TV Region record that has an id = 2, I wrote the following SQL statement:
SELECT query.id AS query_id, cluster_group.name as cluster_name, cluster_group.tv_region_id as cluster_tv_region, store.store_name
FROM query
INNER JOIN cluster_group
ON cluster_group.id=query.cluster_group_id
INNER JOIN store
ON store.id=query.store_id
WHERE cluster_group.tv_region_id = 2
AND store.tv_region_id = 2;
The problem is that it returns zero records even though there are query records that belong to the specified TV Region (via a cluster group or store record). I may have misunderstood how 'inner join' works.
I'm working with Doctrine 2 and have attempted the query using the left join but it still returns nothing, I guess this is because its returning null values too. How do I get it to return only the query records I am interested in and no null values?
Appreciate if someone can point me in the right direction to retrieve the relevant query records.
You will need to use OUTER joins, or possibly LEFT
INNER joins will only return data where there is a matching record on both sides. As you state in your question you only get a match on one side or the other, therefore there is never going to be a matching record across both store and cluster
Jeff Atwood has a good explanation of the join types on his blog http://www.codinghorror.com/blog/2007/10/a-visual-explanation-of-sql-joins.html
Try this:-
SELECT query.id AS query_id, cluster_group.name as cluster_name, cluster_group.tv_region_id as cluster_tv_region, store.store_name
FROM query
LEFT OUTER JOIN cluster_group
ON cluster_group.id=query.cluster_group_id
AND cluster_group.tv_region_id = 2
LEFT OUTER JOIN store
ON store.id=query.store_id
AND store.tv_region_id = 2
EDIT - no experience of doctrine, but you could try using a UNION:-
SELECT query.id AS query_id, cluster_group.name as cluster_name, cluster_group.tv_region_id as cluster_tv_region, NULL AS store_name
FROM query
INNER JOIN cluster_group
ON cluster_group.id=query.cluster_group_id
AND cluster_group.tv_region_id = 2
UNION
SELECT query.id AS query_id, NULL as cluster_name, NULL as cluster_tv_region, store.store_name
FROM query
INNER JOIN store
ON store.id=query.store_id
AND store.tv_region_id = 2
It works like this for me:
from table1 inner join table2 on table1.id = table2.id
inner join table3 on table1.id = table3.id
I have three different SQL tables I need to join:
table "internet" with columns id|type|status
table "type_list" with columns id|type_name
table "status_list" with columns id|status_name
I want to output text from the two other tables (type_list, status_list) but not values as numbers which currently I have in table "internet".
I also don't want to make lazy programming - PHP array to make ID's equal to something like
$type_list = array("1"=>"VDSL2","2"=>"ADSL");
$status_list = array("1"=>"Pending","2"=>"Active");
because the text is already in the tables, i just dont know how to join them and output the text as query combined together in one query.
Use JOIN
SELECT i.id, type_name, status_name
FROM internet i
LEFT OUTER JOIN type_list t ON t.id = i.type
LEFT OUTER JOIN status_list s ON s.id= i.status
Read the MySQL doc for more informations.
Just write the select with the fields you want.
select internet.id,type_name,status_name from internet
inner join type_list
on type_list.id=internet.id
inner join status_list
on status_list.id=internet.id
For this you need a LEFT JOIN, like so:
SELECT i.id, t.type_name, s.status_name
FROM internet AS i
LEFT JOIN type_list AS t ON t.id = i.id
LEFT JOIN status_list AS s ON s.id= i.id
From your question, it is unclear what field you would like to join the queries on. In the above example, the queries are joined on the id field.
Please also note that the AS is not actually necessary, I have just put it in there to make it clear what is going on
I have two tables: 'posts' and 'users' every post has a 'ref_id' column to get the user id who posted it.
Now, I am getting posts this way:
$this->db->query("SELECT * FROM posts WHERE time > '$timeLimit' LIMIT 50");
I can't understand how to join every result to get the poster related data as well. What I am doing right now is basically a loop inside a loop, where foreach of the result, get their user info. But it is pretty obvious that this is very wrong,
Apparently I need to start using joins, but how does one do it? this should be a really simple example to work with, I suppose.
Any help? Thank you.
SELECT posts.*, users.*
FROM posts
INNER JOIN users
ON posts.posted_by = users.id;
Like this:
SELECT
posts.*,,
users.Username
FROM posts
INNER JOIN users ON posts.ref_id = users.user_id;
Explanation:
To JOIN to any tables with each others, there are two things; the JOIN type and the join condition. There are three main types of join:
INNER JOIN, only the rows that match the join condition will be returned from the two tables no more rows. But:
LEFT OUTER JOIN, when you join two tables you will have one on the left of the join keyword and the other one will be in the right:
FROM Table1 <------------- This is the left table.
LEFT OUTER JOIN table2 .... <------------- This is the right table.
In LEFT OUTER JOIN the unmatched rows from the left table will be included in the result set.
RIGHT OUTER JOIN the unmatched rows from the right table will be included in the result set.
CROSS JOIN this will perform a Cartesian product from the two tables.
In our query, the query will reutrn all the users from the users table only if the ref_id equal to the user_id column form the posts table.
For more information and explanations:
A Visual Explanation of SQL Joins.
Another Visual Representation of SQL Joins.
Join syntax in MySQL
SELECT user.name
FROM users
INNER JOIN posts
ON posts.ref_id == user.id
AND posts.time > 50
http://www.w3schools.com/sql/sql_join_inner.asp
I've got a large mysql query with 5 joins which may not seem efficient but I'm struggling to find a different solution which would work.
The views table is the main table here, because both clicks and conversions table rely on it via the token column(which is indexed and set as a foreign key in all tables).
The query:
SELECT
var.id,
var.disabled,
var.name,
var.updated,
var.cid,
var.outdated,
IF(var.type <> 0,'DL','LP') AS `type`,
COUNT(DISTINCT v.id) AS `views`,
COUNT(DISTINCT c.id) AS `clicks`,
COUNT(DISTINCT co.id) AS `conversions`,
SUM(tc.cost) AS `cost`,
SUM(cp.value) AS `revenue`
FROM variants AS var
LEFT JOIN views AS v ON v.vid = var.id
LEFT JOIN traffic_cost AS tc ON tc.id = v.source
LEFT JOIN clicks AS c ON c.token = v.token
LEFT JOIN conversions AS co ON co.token = v.token
LEFT JOIN c_profiles AS cp ON cp.id = co.profile
WHERE var.cid = 28
GROUP BY var.id
The results I'm getting are:
The problem is the revenue and cost results are too hight, because for views,clicks and impressions only the distinct rows are counted, but for revenue and cost for some reason(I would really appreciate an explanation here) all rows in all tables are taken into the result set.
I know this is a large query, but both clicks and conversions tables rely on the views table which is used for filtering the results e.g. views.country = 'uk'. I've tried doing 3 queries and merging them, but that didn't work(it gave me wrong results).
One more thing that I find weird is that if I remove the joins with clicks, conversions, c_profiles the costs column shows correct results.
Any help would be appreciated.
In the end I had to use 3 different queries and do a merge on them. Seemed like an overhead, but worked for me.