First of all, I'm an amateur on SQL. Here it is the example. From this three tables I would like to know how is called the teacher who makes more money with the classes:
Table1:
LessonName TeacherID
Maths 3
Biology 2
Biology 1
Geology 1
Table2:
Lesson PricePerClass
Maths 200
Biology 100
Geology 150
Table3:
IDTeacher TeacherName
1 Mike
2 John
3 Lauren
My main problem is that I don't know how to deal with the repeated values from the first table when I'm doing the triple join.
So far "I've made" this:
select IDTeacher, PricePerClass
from Table1 as T1
inner join Table2 as T2 on t1.LessonName = t2.Lesson
inner join Table3 as T3 on t1.TeacherId = t3.idTeacher
...
And I don't know how to keep going. I will have to group the t1.LessonName but every time I try to do it I get syntax errors. As you can see I'm pretty lost.
EDIT: My expected result would be something like:
IDTeacher TotalRevenue
1 250
Thanks a lot.
join the tables, group by teacher to aggregate and get the top row after you sort by the total descending:
select t3.IDTeacher, sum(t2.PricePerClass) TotalRevenue
from Table3 t3
inner join Table1 as t1 on t1.TeacherId = t3.IDTeacher
inner join Table2 as t2 on t2.Lesson = t1.LessonName
group by t3.IDTeacher
order by TotalRevenue desc limit 1
Note that this query does not return ties, if any.
SELECT t3.IDTeacher, t3.TeacherName, sum(t2.PricePerClass) from table1 t1
inner join table3 t3 on t1.TeacherID = t3.IDTeacher
inner join table2 t2 on t1.Lessonname = t2.Lesson
group by t3.TeacherName
order by sum(t2.PricePerClass) desc limit 1;
Related
Thanks for assisting with the previous query (SQL Query that selects a column in table 1 and uses that to select sum in table 2) of SUM from 2 tables, I now have a additional Condition for 1 of the tables. I would like to add WHERE Group1 = 1 AND IN/OUT = 'OUT'
I have 3 tables,
Names ,Groups
Names ,Payments
Names ,Payments and IN/OUT
I want to only SUM the OUT Payments in Table 3, I am getting total payments only So FAR is have:
SELECT t1.name1, SUM(t2.sale2),SUM(t3.sale3)
FROM table1 t1 JOIN table2 t2 ON t1.name1 = t2.name2
JOIN table3 t3 ON t1.name1 = t3.name3
WHERE group1 = 1
GROUP BY t1.name1
i would also like to add a zero if there is no data to sum instead of removing the whole record, Currently if a name has no payments in Table 3 but has payments in table 2 it deletes the record.
Please check the query below =>
To Get OutPayment group by Name
SELECT t1.Names,SUM(t3.Payments) As OutPayment
FROM TABLE3 as t3
INNER JOIN TABLE1 as t1 ON t1.Names = t3.Names
INNER JOIN TABLE2 as t2 ON t1.Names = t2.Names
WHERE t1.GroupID = 1 AND t3.INOROUT=2 --INOROUT =2 is OUT and 1 is IN
GROUP BY t1.Names;
To Get TotalOutPayment
SELECT SUM(t3.Payments) As TotalOutPayment
FROM TABLE3 as t3
INNER JOIN TABLE1 as t1 ON t1.Names = t3.Names
INNER JOIN TABLE2 as t2 ON t1.Names = t2.Names
WHERE t1.GroupID = 1 AND t3.INOROUT=2; --INOROUT =2 is OUT and 1 is IN
Note: Code is in DBFiddle too Check the Demo Query Link
First of all, I'm an amateur on SQL. Here it is the example. From this three tables I would like to know who are the teachers that make more money than Mike
Table1:
LessonName TeacherID
Maths 3
Biology 2
Biology 4
Geology 1
Table2:
Lesson PricePerClass
Maths 200
Biology 100
Geology 150
Table3:
IDTeacher TeacherName
1 Mike
2 John
3 Lauren
4 Julian
So far I've made this:
select t3.IDTeacher, sum(t2.PricePerClass) TotalRevenue
from Table3 t3
inner join Table1 as t1 on t1.TeacherId = t3.IDTeacher
inner join Table2 as t2 on t2.Lesson = t1.LessonName
group by t3.IDTeacher
where TotalRevenue > (select TotalRevenue
from Table2 as t2
inner join Table1 as t1 on t2.Lesson = t3.LessonName
inner join Table3 as t3 on t3.IDTeacher = t1.TeacherID
where t3.TeacherName = "Mike");
And I don't know how to keep going because when I run it, an error appears.
My expected result would be something like:
IDTeacher TotalRevenue
3 200
Thanks!
In your main query you must use a HAVING clause instead of a WHERE clause and also in the subquery fix your joins:
select t3.IDTeacher, sum(t2.PricePerClass) TotalRevenue
from Table3 t3
inner join Table1 as t1 on t1.TeacherId = t3.IDTeacher
inner join Table2 as t2 on t2.Lesson = t1.LessonName
group by t3.IDTeacher
having TotalRevenue > (
select sum(t2.PricePerClass)
from Table3 t3
inner join Table1 as t1 on t1.TeacherId = t3.IDTeacher
inner join Table2 as t2 on t2.Lesson = t1.LessonName
where t3.TeacherName = "Mike"
);
See the demo.
Results:
| IDTeacher | TotalRevenue |
| --------- | ------------ |
| 3 | 200 |
I am trying to join a table and get a count but I cannot count an ID twice in the table for the count.
Table 1:
ID animal
-- ------
1 dog
2 dog
3 cat
4 cat
5 dog
Table 2:
ID
--
2
2
3
5
5
I need to get a count of how many of each type of animal are in table 2. I can get it to join and change the ID to the type of animal and then get a count of each.
The issue is that each ID can only get counted once. So the expected output would be.
dog:2
cat:1
Where my output is
dog:4
cat:1
Try like below
select t1.animal, count( distinct t2.ID)
from table1 t1 join table2 t2 on t1.ID=t2.ID
group by t1.animal
You can try below using count distinct id
select b.animal,count(distinct a.id) from table2 a
inner join table1 b on a.id=b.id
group by b.animal
Try this:
SELECT t1.animal AS "Animal", COUNT(DISTINCT t1.ID) AS "No. of Animals"
FROM TABLE2 t2, TABLE1 t1
WHERE t2.ID = t1.ID
GROUP BY t1.animal
You can Try Nested Selects here.
SELECT
t.animal,
COUNT(t.ID) AS Count
FROM
(SELECT DISTINCT a.animal, b.ID FROM table1 a INNER JOIN table2 b ON a.ID = b.ID)t
GROUP BY t.animal
this is tested image
I would like to left join three tables in one result and when I'm doing it like that: http://sqlfiddle.com/#!9/546c24/2 my result is wrong as you see.
I want COUNT(Test2.id) to be 2 and SUM(Test3.positive) to be 3 and not both 6.
That's my problem. I hope it's understandable.
You are getting a Cartesian product for each test1.id. You need to aggregate before the JOINs:
SELECT t1.id,Test1.name, t2.cnt_2,
t3.sum_pos, t3.sum_neg
FROM Test1 t1 LEFT JOIN
(SELECT ID_Test1, COUNT(*) as cnt_2
FROM Test2
GROUP BY ID_Test1
) t2
ON t1.id = t2.ID_Test1 LEFT JOIN
(SELECT ID_Test1, SUM(positive) as sum_pos, SUM(negative) as sum_neg
FROM Test3
GROUP BY ID_Test1
) t3
ON t1.id = t3.ID_Test1
GROUP BY t1.id;
Here is the SQL Fiddle.
I have three tables
t1
CustId Name
1 XYZ
2 PQR
t2
CustId Income
1 100
1 200
2 50
2 100
t3
CustId Expense
1 50
1 70
2 30
2 40
I need to run a query where I get the below result
CustId Total Income Total Expense
1 300 120
2 150 70
I have tried the normal SUM and Group By but the result is very different from the expected...
The Query I attempted was
SELECT t1.custid, SUM(t2.Income), SUM(t3.Expense) FROM t1
LEFT JOIN t2 ON t1.custId = t2.CustId
LEFT JOIN t3 ON t1.CustId = t3.CustId
GROUP BY t1.CustId
Any help you would appreciated....
Try below query.
SELECT t1.CustID, IFNULL(tbl1.Income,0) AS 'TotalIncome', IFNULL(tbl2.Expenses,0) AS 'TotalExpenses'
FROM t1
LEFT JOIN (SELECT t2.CustID,SUM(Income) AS 'Income' FROM t2 GROUP BY t2.CustID) tbl1
ON t1.CustID = tbl1.CustID
LEFT JOIN (SELECT t3.CustID,SUM(Expenses) AS 'Expenses' FROM t3 GROUP BY t3.CustID) tbl2
ON t1.CustID = tbl2.CustID;
SQL Fiddle: http://sqlfiddle.com/#!9/ad05d/8
Try doing inner join all three tables and then grouping the result by customer id like:
SELECT t1.custId, SUM(t2.Income), SUM(t3.expense)
FROM t1 INNER JOIN t2
ON t1.custId = t2.custId
INNER JOIN t3
ON t2.custId = t3.custId
GROUP BY t1.custId
You can use the following query to achieve what you want
SELECT t1.custid, ti.Income, te.expense FROM t1 LEFT JOIN (select t2.custId, sum(t2.Income) as income from t2 group by t2.custId) as ti ON t1.custId = ti.CustId LEFT JOIN (select t3.custId, sum(t3.Expense) as expense from t3 group by t3.custId) as te ON t1.CustId = te.CustId
As far as why your previous query did not worked. I can give the following explanation.
In SQL when ever you do a join, the way database internally makes a cartesian product of all the entries and depending on the where clause the data is returned. So when you did
SELECT t1.custid, SUM(t2.Income), SUM(t3.Expense) FROM t1 LEFT JOIN t2 ON t1.custId = t2.CustId
You got 4 rows, where customerId is repeated in the rows, now when you join with t3 table by applying the equal condition on customerId, database would be able to match customerID in two records and hence you get 8 rows. That is why your query was not working