I have two tables in MySQL:
___Table1
| id | name |
|----|------|
| 98 | Fred |
___Table2
| link | amount |
|------|--------|
| 98 | 100.00 |
| 98 | 50.00 |
How can I SELECT all the items from ___Table1 and SUM datas from the ___Table2.
The desired output should be:
Fred = 150.00
This is what I have tried so far:
SELECT
SELECT SUM(amount) AS amount FROM ___Table2 WHERE ___Table2.link = ___Table1.id,
(SELECT * FROM ___Estimates ORDER BY EST_Id DESC)
Thanks.
SELECT
t1.id AS id,
t1.name as name,
IFNULL ( SUM( t2.amount ), 0 ) AS account
FROM
___Table2 t2
RIGHT JOIN ___Table1 t1 ON t2.link = t1.id
GROUP BY
t2.link
You could group by name instead but you didn't say if it was unique. If you just need a single user then add a where clause to select that user:
select name, sum(amount) as 'sum'
from ___Table1
join ___Table2 on ___Table1.id = ___Table2.link
group by ___Table1.id
Those table names are awful (you can't tell how many underscores by just looking at it), also it's a good idea to use the same name for the primary and foreign key (_id is the often used standard).
Related
My table:
id | request | subject | date
1 | 5 | 1 | 576677
2 | 2 | 3 | 576698
3 | 5 | 1 | 576999
4 | 2 | 3 | 586999
5 | 2 | 7 | 596999
Need to select unique records by two columns(request,subject). But if we have different pairs of request-subject(2-3, 2-7), this records should be excluded from resulted query.
My query now is:
SELECT MAX(id), id, request, subject, date
FROM `tbl`
GROUP BY request, subject
having count(request) > 1
order by MAX(id) desc
How to exclude record with id=4, id=5 from this query? Thanks!
You may group by request, and then check for every group if all subjects in it are equal. You could do it using MIN() and MAX():
SELECT request, MIN(subject) AS subject
FROM table_1
GROUP BY request
HAVING MIN(subject) = MAX(subject)
As for your update, I assume you want all the fields for the max ID in the group (in your example, ID 3). The query would then look like this one:
SELECT *
FROM table_1 t
WHERE t.id IN (SELECT MAX(s.id)
FROM table_1 s
GROUP BY s.request
HAVING MIN(s.subject) = MAX(s.subject))
ORDER BY t.id
You can try this.
select * from MyTable T1
WHERE NOT EXISTS( SELECT * FROM MyTable T2
WHERE T1.id <> T2.id
and T1.request = T2.request
and T1.subject <> T2.subject)
Sql Fiddle
This is my example dataset I have groups with students assigned to them as shown below
uid | groupid | studentid
49 | PZV7cUZCnLwNkSS | wTsBSkkg4Weo8R3
50 | PZV7cUZCnLwNkSS | aIuDhxfChg3enCf
97 | CwvkffFcBCRbzdw | hEwLxJmnJmZFAic
99 | CwvkffFcBCRbzdw | OKFfl58XVQMrAyC
126 | CwvkffFcBCRbzdw | dlH8udyTjNV3nXM
142 | 2vu1eqTCWVjgE58 | Q01Iz3lC2uUMBSB
143 | 2vu1eqTCWVjgE58 | vB5s8hfTaVtx3wO
144 | 2vu1eqTCWVjgE58 | 5O9HA5Z7wVhgi6l
145 | 2vu1eqTCWVjgE58 | OiEUOXNjK2D2s8F
I am trying to output with the following information.
The problem I am having is the Group Size column getting it to output a count.
Studentid | Groupid | Group Size
wTsBSkkg4Weo8R3 | PZV7cUZCnLwNkSS | 2
aIuDhxfChg3enCf | PZV7cUZCnLwNkSS | 2
hEwLxJmnJmZFAic | CwvkffFcBCRbzdw | 3
OKFfl58XVQMrAyC | CwvkffFcBCRbzdw | 3
dlH8udyTjNV3nXM | CwvkffFcBCRbzdw | 3
I have researched if I can you can use a where clause in the count, and does not seem like it will let me do that. I thought about doing a sum but couldn't make that happen either. I feel like I am missing something simple.
An easy way to solve this, is using a JOIN statement:
SELECT a.studentid AS Studentid, a.groupid AS Groupid, COUNT(*)
FROM table AS a
JOIN table AS b ON a.groupid = b.groupid
GROUP BY a.studentid, a.groupid
So here we join the table with itself and use a GROUP BY to group on the studentid and groupid and then use COUNT(*) to count the number of rows in b that have the same groupid.
Try this:
SELECT *
FROM pony a
LEFT JOIN (
SELECT COUNT(*), groupid
FROM pony
GROUP BY groupid
) b ON a.groupid = b.groupid
try this
SELECT T1.Studentid, T1.Groupid, T2.GroupCount
FROM Your_Table T1
INNER JOIN ( SELECT Groupid, count(*) AS GroupCount FROM Your_Table GROUP BY Groupid ) T2
ON T1.Groupid = T2.Groupid
You should try:
SELECT COUNT(Groupid) AS Groupsize FROM table;
It seems that what you're trying to do is simple. If I understand correctly, a simple SELECT COUNT statement. To exclude multiple returns of the same value, use SELECT DISTINCT COUNT()
So i have the following table:
userid | name | referralcode
When users register on the website they put the referralcode of someone else (the referral code is the same number as the userid of someone else)
so im looking for a sql query that will output something like this
20 (this means 20 users have this userid on their referral code) , Gerardo Bastidas, Valencia
10 , Juan Bastidas, Valencia
I want to get all info on user. its all located in the same table.
Try this query:
SELECT yt1.*, COALESCE(yt2.referral_count, 0)
FROM yourtable yt1 LEFT JOIN
(
SELECT t1.userid, COUNT(*) AS referral_count
FROM yourtable t1 INNER JOIN yourtable t2
ON t1.userid = t2.referralcode
GROUP BY t1.userid
) yt2
ON yt1.userid = yt2.userid;
This query does a self-join and will list every user along with the number of referral codes where his userid appears.
This code will do the work in one query. Replace your table name with 'tbName'
Tested and working
SELECT countval, userid, email, address
FROM tbName t1 LEFT JOIN
(
SELECT COUNT(t2.userid) ASs countval, tt.userid AS xx
FROM tbName t2
GROUP BY t2.referralcode
) t3
ON t3.xx = t1.userid
Output:
+-------+-----+------+
| count | uid | name |
+-------+-----+------+
| 3 | 1 | abc |
| 2 | 2 | xyz |
| 5 | 3 | kmn |
+-------+-----+------+
I'm having trouble with subqueries and COUNT() using multiple tables in MySQL.
For example, I have two tables:
t1
id | name
42 | John
22 | Mary
77 | Nick
t2
userid | merchandise | type
22 | Skirt | clothes
22 | Scarf | clothes
22 | Purse | clothes
77 | Grill | home
22 | Pen | office
42 | Jacket | clothes
I want to count the types in table 2 by using both tables. So for example, a desired output will be:
Number of clothes purchased for each user
name | count_clothes
Mary | 3
John | 1
Nick | 0
The best MySQL query I came up with so far is:
SELECT t1.name, (
SELECT COUNT(*) FROM t2 WHERE type = 'clothes'
) as count_clothes
FROM users
ORDER BY count_clothes;
But the output it's giving me is:
name | count_clothes
Mary | 3
John | 3
Nick | 3
I know the flaw is my COUNT() query. I've tried matching the ID columns but it keeps returning an error saying subquery is returning more than 1 row.
Join the tables rather than using a subquery.
SELECT t1.name, IFNULL(COUNT(t2.userid), 0) AS count_clothes
FROM users t1
LEFT JOIN t2 ON t1.id = t2.userid and t2.type = 'clothes'
GROUP BY t1.name
ORDER BY count_clothes DESC
DEMO
You need to use LEFT JOIN rather than INNER JOIN in order to get the users with zero clothes. And you have to count t2.userid rather than COUNT(*) so it doesn't count the null matches.
The problem with your subquery is that the WHERE clause didn't select a specific userid, so it just counted all users every time.
You can use join and SUM() with expression ,using sum with expression will evaluate it as boolean 1 or 0 based on expression result,so it will work as a count
SELECT u.id,
SUM(uc.`type`='clothes') count_clothes
FROM users u
LEFT JOIN user_clothes uc ON(u.id =uc.user_id)
GROUP BY u.id
ORDER BY count_clothes;
If you still want to use a subquery you need to use it like as co-related subquery,but sometimes it lacks performance so it is not recommended
SELECT t1.name, (
SELECT COUNT(*) FROM t2 WHERE type = 'clothes' AND t1.id=user_id
) as count_clothes
FROM users t1
ORDER BY count_clothes;
Try this
SELECT t1.name,
IFNULL(count(t2.userid),0) AS count_clothes
FROM t1
LEFT JOIN t2 ON t1.id=t2.userid
WHERE t2.type="clothes"
GROUP BY t2.userid
I have a table as so...
----------------------------------------
| id | name | group | number |
----------------------------------------
| 1 | joey | 1 | 2 |
| 2 | keidy | 1 | 3 |
| 3 | james | 2 | 2 |
| 4 | steven | 2 | 5 |
| 5 | jason | 3 | 2 |
| 6 | shane | 3 | 3 |
----------------------------------------
I'm running a select like so:
SELECT * FROM table WHERE number IN (2,3);
The problem im trying to solve is that I want to only grab get results from groups that have 1 or more rows of each number. For instance the above query is returning id's 1-2-3-5-6, when I'd like the results to exclude id 3 since the group of '2' can only return 1 result for the number of '2' and not for BOTH 2 and 3, since there's no row with the number 3 for the group 2 i'd like it to not even select id 3 at all.
Any help would be great.
Try it this way
SELECT *
FROM table1 t
WHERE number IN(2, 3)
AND EXISTS
(
SELECT *
FROM table1
WHERE number IN(2, 3)
AND `group` = t.`group`
GROUP BY `group`
HAVING MAX(number = 2) > 0
AND MAX(number = 3) > 0
)
or
SELECT *
FROM table1 t JOIN
(
SELECT `group`
FROM table1
WHERE number IN(2, 3)
GROUP BY `group`
HAVING MAX(number = 2) > 0
AND MAX(number = 3) > 0
) q
ON t.`group` = q.`group`;
or
SELECT *
FROM table1
WHERE `group` IN
(
SELECT `group`
FROM table1
WHERE number IN(2, 3)
GROUP BY `group`
HAVING MAX(number = 2) > 0
AND MAX(number = 3) > 0
);
Sample output (for both queries):
| ID | NAME | GROUP | NUMBER |
|----|-------|-------|--------|
| 1 | joey | 1 | 2 |
| 2 | keidy | 1 | 3 |
| 5 | jason | 3 | 2 |
| 6 | shane | 3 | 3 |
Here is SQLFiddle demo
On this, you can approach from a fun way with multiple joins for what you WANT qualified, OR, apply a prequery to get all qualified groups as others have suggested, but readability is a bit off for me..
Anyhow, here's an approach going through the table once, but with joins
select DISTINCT
T.id,
T.Name,
T.Group,
T.Number
from
YourTable T
Join YourTable T2
on T.Group = T2.Group AND T2.Group = 2
Join YourTable T3
on T.Group = T3.Group AND T3.Group = 3
where
T.Number IN ( 2, 3 )
So on the first record, it is pointing to by it's own group to the T2 group AND the T2 group is specifically a 2... Then again, but testing the group for the T3 instance and T3's group is a 3.
If it cant complete the join to either of the T2 or T3 instances, the record is done for consideration, and since indexes work great for joins like this, make sure you have one index for your NUMBER criteria, and another index on the (GROUP, NUMBER) for those comparisons and the next query sample...
If doing by more than this simple 2, but larger group, prequery qualified groups, then join to that
select
YT2.*
from
( select YT1.group
from YourTable YT1
where YT1.Number in (2, 3)
group by YT1.group
having count( DISTINCT YT1.group ) = 2 ) PreQualified
JOIN YourTable YT2
on PreQualified.group = YT2.group
AND YT2.Number in (2,3)
Maybe this,if I understand you
SELECT id FROM table WHERE `group` IN
(SELECT `group` FROM table WHERE number IN (2,3)
GROUP BY `group`
HAVING COUNT(DISTINCT number)=2)
SQL Fiddle
This will return all ids where BOTH numbers exist in a group.Remove DISTINCT if you want ids for groups where just one numbers is in.