say i had the following tables
user_table
id username
1 abc
2 def
3 ghij
courses_table
id title
1 csc
2 math
3 syn
user_courses
user_id course_id
2 1
1 3
2 3
i want to select the username whos taking course 1 AND 3 ,
not at least 1 or 3 , i mean both 1 and 3
i've tried the following mysql queries
SELECT DISTINCT u.* FROM user_table as u LEFT JOIN user_courses as uc ON uc.user_id = u.id WHERE uc.course_id = 1 AND uc.course_id=3;
SELECT DISTINCT u.* FROM user_table as u LEFT JOIN user_courses as uc ON uc.user_id = u.id WHERE uc.course_id IN (1,3);
SELECT DISTINCT u.* FROM user_table as u LEFT JOIN user_courses as uc ON uc.user_id = u.id WHERE uc.course_id IN (1,3) AND uc.user_id = u.id ;
the first and third queries executed with no results shown , and the second one show all users who had at least course_id 1 or 3
if you are wondering why am i using the LEFT JOIN , this is because i need to join table's results , and the above line of code is just an example , and im using to get data from about 9 tables using the LEFT join .
any help please ? thanks
SELECT DISTINCT u.* FROM user_table as u LEFT JOIN user_courses as uc ON uc.user_id = u.id WHERE uc.course_id IN( 1,3) AND uc.user_id = 2 ";
this show me the result i want , its output "def" ,
but i can't use the user_id as a static value ( number 2 in this example )
This problem is called Relational Division
SELECT a.id, a.username
FROM user_table a
INNER JOIN user_courses b
ON a.id = b.user_ID
WHERE b.course_ID IN (1,3)
GROUP BY a.id, a.username
HAVING COUNT(*) = 2
SQL of Relational Division
If course_ID is not unique for every users considering that the user have retake the course, a DISTINCT keyword is needed to coung unique courses,
SELECT a.id, a.username
FROM user_table a
INNER JOIN user_courses b
ON a.id = b.user_ID
WHERE b.course_ID IN (1,3)
GROUP BY a.id, a.username
HAVING COUNT(DISTINCT b.course_ID) = 2
SQLFiddle Demo
OUTPUT
╔════╦══════════╗
║ ID ║ USERNAME ║
╠════╬══════════╣
║ 2 ║ def ║
╚════╩══════════╝
please try this:
SELECT
U.id,
U.username
FROM
user_courses UC
INNER JOIN user_table U
ON UC.`user_id` = U.`id`
WHERE UC.`course_id` = 1
OR UC.`course_id` = 3
GROUP BY U.`id`
HAVING COUNT(*) > 1
Related
Table mpkids_students AS A
id BranchId Email Mobile StudentId
9497 25 mpsuraj2016#gmail.com 8700698773 25
9498 25 m016#gmail.com 8700698776 26
Table mpkids_student_image_gallery AS B
id like_count student_id
1 25 27
Table mpkids_visitors AS C
id student_id
1 9497
2 9497
3 9497
Table mpkids_visitors_count AS D
id visitor_count student_id
1 4 23
Table mpkids_image_likes AS E
id student_id
1 67
Table mpkids_relatives_data AS F
id student_id rel_email rel_mobile
1 9497 kushwahji#gmail.com 9009859691
2 9497 kushwah#gmail.com 7566403326
3 9497 kushwah#gmail.com 1236403326
4 9497 suraj#gmail.com 123640332
Table mpkids_paidstatus AS G
id student_id Received
1 9497 7500
2 9497 3000
3 9497 3000
MYSQL QUERY
SELECT A.id as student_id,
COUNT(DISTINCT B.id) as images,
COUNT(DISTINCT C.id)+ COUNT(DISTINCT D.visitor_count) as visits,
count(DISTINCT E.id) + SUM(B.like_count) as likes,
COUNT(DISTINCT A.Email)+COUNT(DISTINCT F.rel_email) as emails,
COUNT(DISTINCT A.Mobile)+COUNT(DISTINCT F.rel_mobile) as moibles,
SUM(G.Received) as Received
FROM mpkids_students AS A
LEFT JOIN mpkids_student_image_gallery AS B ON B.student_id = A.id
LEFT JOIN mpkids_visitors AS C ON C.student_id = A.id
LEFT JOIN mpkids_visitors_count AS D ON D.student_id = A.id
LEFT JOIN mpkids_image_likes AS E ON E.student_id = A.id
LEFT JOIN mpkids_relatives_data AS F ON F.student_id = A.id
LEFT JOIN mpkids_paidstatus AS G ON G.student_id = A.id
WHERE A.BranchId = 25
GROUP BY A.id
ORDER BY A.StudentId DESC
Result:
student_id images visits likes emails moibles Received
9497 0 3 NULL 4 5 202500
9498 0 0 NULL 1 1 NULL
Problem Explanation:
Received Field returning wrong value i have tried many queries but not getting solution
Received Field correct value 13500 for student_id = 9497
Please help me to find solution.
You are getting wrong output because, when you are joining based on studentid, you are getting multiple records from mpkids_paidstatus table for each student, which is adding up and returning a wrong output.
You can also write your query like following using subquery.
SELECT A.id as student_id,
COUNT(DISTINCT B.id) as images,
COUNT(DISTINCT C.id)+ COUNT(DISTINCT D.visitor_count) as visits,
count(DISTINCT E.id) + SUM(B.like_count) as likes,
COUNT(DISTINCT A.Email)+COUNT(DISTINCT F.rel_email) as emails,
COUNT(DISTINCT A.Mobile)+COUNT(DISTINCT F.rel_mobile) as moibles,
(select SUM(Received) from mpkids_paidstatus ps where ps.student_id=a.id) as Received
FROM mpkids_students AS A
LEFT JOIN mpkids_student_image_gallery AS B ON B.student_id = A.id
LEFT JOIN mpkids_visitors AS C ON C.student_id = A.id
LEFT JOIN mpkids_visitors_count AS D ON D.student_id = A.id
LEFT JOIN mpkids_image_likes AS E ON E.student_id = A.id
LEFT JOIN mpkids_relatives_data AS F ON F.student_id = A.id
WHERE A.BranchId = 25
GROUP BY A.id
ORDER BY A.StudentId DESC
I have two tables
**users**
id name
1 Name1
2 Name2
**tasks**
id user_id title
1 1 Task1
2 1 Task2
3 2 Task3
My request:
SELECT
U.*,
COUNT(T.id) AS tasks_total
FROM
`#__users` AS U
LEFT JOIN
`#__tasks` AS T
ON
U.id = T.user_id
I think something wrong here...
I wan't to get results:
id name tasks_total
1 Name1 2
2 Name2 1
Thanks!
You forgot to group the result by id
SELECT
U.*,
COUNT(T.id) AS tasks_total
FROM
`#__users` AS U
LEFT JOIN
`#__tasks` AS T
ON
U.id = T.user_id
group by U.id
demo on sqlfiddle
You're mixing line functions and aggregate functions. One way around this is to have the aggregation done in a subquery:
SELECT
U.*,
tasks_total
FROM
`#__users` AS U
LEFT JOIN
(SELECT user_id, COUNT(*) AS tasks_total
FROM `#__tasks`
GROUP BY user_id) AS T
ON
U.id = T.user_id
I have the two tables:
user_groups
id name created_user
1 gn1 3
2 gn2 3
user_group_has_users
group_id user_id
2 5
2 6
I want to count the users per group and an output similar this:
id name user_count
2 gn2 2
1 gn1 0
I tried this query
select g.*,
count(cg.user_id) as user_count
from user_groups as g
left join user_group_has_users as cg on cg.user_group_id = g.id
where g.created_user = 3
But it only returns one row. I do not understand why this happening.
Please help me on this.
Use this query
SELECT g.* ,COUNT(cg.user_id) AS user_count
FROM user_groups g
LEFT JOIN user_group_has_users cg ON cg.group_id = g.id
WHERE g.created_user = 3
GROUP BY g.id
ORDER BY user_count DESC ;
Left join with where condition is nothing but inner join. You may want as
select
ug.id,
ug.name,
count(ughu.user_id) as user_count
from user_groups ug
left join user_groups_has_users ughu on ughu.group_id = ug.id
and ug.created_user = 3
group by ug.id
order by user_count desc ;
If you still want to filter the data with the created_user = 3 then use inner join and move the condition to where clause
Be careful with aggregates and JOINs. In some cases the numbers are inflated.
See if this works for you:
select g.*,
( SELECT count(*)
FROM user_group_has_users
WHERE user_group_id = g.id
) AS user_count
from user_groups as g
where g.created_user = 3
I have two tables in mysql database
groups
id|name
_______
1 |red
2 |blue
3 |green
4 |white
and users
id|name |group
_______________
1 |joe |1
2 |max |1
3 |anna |2
4 |lisa |2
So... joe and max are in the "red" group, anna and lisa are in the "blue" group.
How can I make simple listing of groups which would contain the number of
persons in that group
For example
red - 2
blue - 2
green - 0
white - 0
Most the other answers are basically correct, but forgot an important detail: GROUP is a reserved word in SQL, so your column name must be escaped:
SELECT groups.name, COUNT(*) AS total_members
FROM groups
LEFT OUTER JOIN users
ON users.`group` = groups.id
GROUP BY groups.id
check if this works....
SELECT COUNT(*), groups.name FROM groups, users WHERE users.group=groups.id GROUP BY groups.name
UPDATE
SELECT groups.name, COUNT(users.*) FROM groups LEFT JOIN users
ON groups.id=users.group GROUP BY groups.name
this will keep the colors even if they dont have any name related
Give this a try:
select g.name, count(u.id) from groups g
left join users u on g.id = u.group
group by g.id, g.name
Try this
SELECT COUNT(g.id) as count, g.name
FROM groups as g
LEFT JOIN users as u
ON u.group = g.id
GROUP BY g.id
This should work
SELECT g.*, COUNT(DISTINCT u.id) FROM `groups` g
INNER JOIN `users` u on g.id = u.group
GROUP BY u.id
maybe this should work
SELECT g.name, COUNT( u.id ) AS Totoal
FROM `groups` g
INNER JOIN `users` u ON g.id = u.group
GROUP BY g.id
I have a table named friends;
friends
id uid fid
1 1 2 (1 is a friend of 2 and vice versa)
2 1 3 (1 is a friend of 3 and vice versa)
3 4 1 (1 is a friend of 4 and vice versa)
4 5 1 (1 is a friend of 5 and vice versa)
And a corresponding table for users;
users
uid name
1 mike
2 john
3 karl
4 mary
5 tony
This doesn't seem to do the trick:
SELECT name FROM users LEFT JOIN friends ON friends.uid=users.uid WHERE friends.uid='1' OR friends.fid='1'
What should my query be to get all the names of mike's friends?
This should do it just fine with a single, easy to index, query;
SELECT name FROM users u
JOIN friends f
ON u.uid = f.uid OR u.uid = f.fid
WHERE (f.uid=1 OR f.fid=1)
AND u.uid<>1;
Demo here.
Untested:
SELECT name from friends LEFT JOIN users on users.uid=friends.fid where friends.uid=1 UNION
SELECT name from friends LEFT JOIN users on users.uid=friends.uid where friends.fid=1
This may look a little strange if anyone is ever friends with themselves.
try one of these:
SELECT a.uid as UserID,
a.`Name` as UserName,
c.`Name as FriendsName
FROM users a LEFT JOIN friends b on a.uid = b.uid
LEFT JOIN users c on b.fid = c.uid
OR
SELECT a.uid as UserID,
a.`Name` as UserName,
GROUP_CONCAT(c.`Name`) as FriendsList
FROM users a LEFT JOIN friends b on a.uid = b.uid
LEFT JOIN users c on b.fid = c.uid
GROUP BY a.uid
As in your prequel question, you need to cover both foreign keys to the user table to get all his friends:
SELECT users.*
FROM (
SELECT uid FROM friends WHERE fid = 1
UNION ALL
SELECT fid FROM friends WHERE uid = 1
) f
JOIN users USING (uid)
Switch friends and users in your query and I think you'll get what you want.
In other words:
SELECT name FROM friends LEFT JOIN users ON friends.uid=users.uid WHERE friends.uid='1' OR friends.fid='1'
I think this is right SELECT name FROM users LEFT JOIN friends ON friends.uid=users.uid WHERE friends.uid=1 OR friends.fid=1