I have two tables as follows:
Table1:
ID | FName | LName
1 | A1 | A2
2 | B1 | B2
3 | C1 | C2
Table2:
ID | Price | Month | T1ID
1 | 5 | 1 | 1
2 | 5 | 1 | 2
3 | 5 | 2 | 3
Result:
Where Month = '1'
ID | FName | LName | Price | Month | T1ID
1 | A1 | A2 | 5 | 1 | 1
2 | B1 | B2 | 5 | 1 | 2
NULL| C1 | C2 | NULL | NULL | 3
Where Month = '2'
ID | FName | LName | Price | Month | T1ID
NULL| A1 | A2 | NULL | NULL | 1
NULL| B1 | B2 | NULL | NULL | 2
3 | C1 | C2 | 5 | 2 | 3
Looks like a left join with multiple join conditions:
SELECT t2.ID, t1.FName, t1.LName, t2.Price, t2.Month, t1.ID
FROM Table1 t1
LEFT JOIN Table2 t2 ON t1.ID = t2.T1ID AND t2.Month = '1' -- or '2'
The trick is to do filtering by adding additional condition to ON clause, which helps to filter records during the join. If you used the condition in WHERE clause, some records would be filtered out from the results, which is not what you expect.
Related
I have a Microsoft SQL Server with the following tables:
Projects
BookedHours (with fk_Project = Projects.ID)
Products
ProjectsToProducts (n:m with fk_Projects = Projects.ID and fk_Products = Products.ID)
I now want to select how many hours are booked to which product per month. The problem is, that one project can have multiple products (that's why I need the n:m table).
If I do the following, it will count the hours twice if a project has two products.
SELECT
P.ID AS fk_Product, MONTH(B.Datum) AS Monat, SUM(B.Hours) AS Stunden
FROM
tbl_BookedHours AS B
INNER JOIN
tbl_Projects AS M on B.fk_Project = M.ID
INNER JOIN
tbl_ProjectProduct AS PP ON PP.fk_Project = M.ID
INNER JOIN
tbl_Products AS P ON PP.fk_Product = P.ID
WHERE
YEAR(B.Datum) = 2020
GROUP BY
P.ID, MONTH(B.Datum)
ORDER BY
P.ID, MONTH(B.Datum)
I can get the number of products for each project with this SQL:
SELECT fk_Project, COUNT(*) AS Cnt
FROM tbl_ProjectProduct
GROUP By fk_MainProject
But how can I now divide the hours for each project by its individual factor and add it all up per product and month?
I could do it in my C# program or I could use a cursor and iterate through all projects, but I think there should be an more elegant way.
Edit with sample data:
|----------------| |----------------| |------------------------------|
| tbl_Projects | | tbl_Products | | tbl_ProjectProduct |
|----------------| |----------------| |------------------------------|
| ID | Name | | ID | Name | | ID | fk_Project | fk_Product |
|----+-----------| |----+-----------| |------------------------------|
| 1 | Project 1 | | 1 | Product 1 | | 1 | 1 | 1 |
| 2 | Project 2 | | 2 | Product 2 | | 2 | 1 | 2 |
| 3 | Project 3 | | 3 | Product 3 | | 3 | 2 | 1 |
| 4 | Project 4 | | 4 | Product 4 | | 4 | 3 | 3 |
|----------------| |----------------| | 5 | 4 | 1 |
| 6 | 4 | 2 |
| 7 | 4 | 4 |
|------------------------------|
|--------------------------------------|
| tbl_BookedHours |
|--------------------------------------|
| ID | fk_Project | Hours | Date |
|--------------------------------------|
| 1 | 1 | 10 | 2020-01-15 |
| 2 | 1 | 20 | 2020-01-20 |
| 3 | 2 | 10 | 2020-01-15 |
| 4 | 3 | 30 | 2020-01-18 |
| 5 | 2 | 20 | 2020-01-20 |
| 6 | 4 | 30 | 2020-01-25 |
| 7 | 1 | 10 | 2020-02-15 |
| 8 | 1 | 20 | 2020-02-20 |
| 9 | 2 | 10 | 2020-02-15 |
| 10 | 3 | 30 | 2020-03-18 |
| 11 | 2 | 20 | 2020-03-20 |
| 12 | 4 | 30 | 2020-03-25 |
|--------------------------------------|
The Result should be:
|----------------------------|
| fk_Product | Month | Hours |
|----------------------------|
| 1 | 1 | 55 |
| 2 | 1 | 25 |
| 3 | 1 | 30 |
| 4 | 1 | 10 |
| 1 | 2 | 25 |
| 2 | 2 | 15 |
| 1 | 3 | 30 |
| 2 | 3 | 10 |
| 3 | 3 | 30 |
| 4 | 3 | 10 |
|----------------------------|
For example booking Nr. 1 has to be divided by 2 (because Project 1 has two products) and one half of amount added to Product 1 and the other to Product 2 (Both in January). Booking Nr. 4 should not be divided, because Project 3 only has one product. Booking Numer 12 for example has to be divided by 3.
So that in total the Hours in the end add up to the same total.
I hope it's clearer now.
*** EDIT 2***
DECLARE #tbl_Projects TABLE (ID INT, [Name] VARCHAR(MAX))
INSERT INTO #tbl_Projects VALUES
(1,'Project 1'),
(2,'Project 2'),
(3,'Project 3'),
(4,'Project 4')
DECLARE #tbl_Products TABLE (ID INT, [Name] VARCHAR(MAX))
INSERT INTO #tbl_Products VALUES
(1,'Product 1'),
(2,'Product 2'),
(3,'Product 3'),
(4,'Product 4')
DECLARE #tbl_ProjectProduct TABLE (ID INT, fk_Project int, fk_Product int)
INSERT INTO #tbl_ProjectProduct VALUES
(1,1,1),
(2,1,2),
(3,2,1),
(4,3,3),
(5,4,1),
(6,4,2),
(7,4,4)
DECLARE #tbl_BookedHours TABLE (ID INT, fk_Project int, Hours int, [Date] Date)
INSERT INTO #tbl_BookedHours VALUES
(1,1,10,'2020-01-15'),
(2,1,20,'2020-01-20'),
(3,2,10,'2020-01-15'),
(4,3,30,'2020-01-18'),
(5,2,20,'2020-01-20'),
(6,4,30,'2020-01-25'),
(7,1,10,'2020-02-15'),
(8,1,20,'2020-02-20'),
(9,2,10,'2020-02-15'),
(10,3,30,'2020-03-18'),
(11,2,20,'2020-03-20'),
(12,4,30,'2020-03-25')
SELECT P.ID AS fk_Product, MONTH(B.Date) AS Month, SUM(B.Hours) AS SumHours
FROM #tbl_BookedHours AS B INNER JOIN #tbl_Projects AS M on B.fk_Project = M.ID
INNER JOIN #tbl_ProjectProduct AS PP ON PP.fk_Project = M.ID
INNER JOIN #tbl_Products AS P ON PP.fk_Product = P.ID
GROUP BY P.ID,MONTH(B.Date)
ORDER BY P.ID, MONTH(B.Date)
This gives me the wrong result, because it Counts the hours for both products:
| fk_Product | Month | SumHours |
|-------------------------------|
| 1 | 1 | 90 |
| 1 | 2 | 40 |
| 1 | 3 | 50 |
| 2 | 1 | 60 |
| 2 | 2 | 30 |
| 2 | 3 | 30 |
| 3 | 1 | 30 |
| 3 | 3 | 30 |
| 4 | 1 | 30 |
| 4 | 3 | 30 |
|-------------------------------|
Consider the following query. I modified your table variables to temp tables so it was easier to debug.
;WITH CTE AS
(
SELECT fk_Project, count(fk_Product) CNT
FROM #tbl_ProjectProduct
GROUP BY fk_Project
)
,CTE2 AS
(
SELECT t1.Date, t2.fk_Project, Hours/CNT NewHours
FROM #tbl_BookedHours t1
INNER JOIN CTE t2 on t1.fk_Project = t2.fk_Project
)
SELECT t4.ID fk_Product, MONTH(date) MN, SUM(NewHours) HRS
FROM CTE2 t1
INNER JOIN #tbl_Projects t2 on t1.fk_Project = t2.id
INNER JOIN #tbl_ProjectProduct t3 on t3.fk_Project = t2.ID
INNER JOIN #tbl_Products t4 on t4.ID = t3.fk_Product
GROUP BY t4.ID,MONTH(date)
I have got two tables 'Customer'.
The first one:
ID | UserID | Date
1. | 1 | 2018-05-01
2. | 1 | 2018-05-02
The second one:
ID | UserID | Date
1. | 1 | 2018-05-01
2. | 1 | 2018-05-02
3. | 1 | 2018-05-03
So, as you can see in the second table, there is one row more.
I have written so far this code:
;with cte_table1 as (
select UserID, count(id) cnt from db1.Customer group by UserID
),
cte_table2 as (
select UserID, count(id) cnt from db2.Customer group by UserID
)
select * from cte_table1 t1
join cte_table2 t2 on t2.UserID = t1.UserID
where t1.cnt <> t2.cnt
and this gives me expected result:
UserID | cnt | UserID | cnt
1 | 2 | 1 | 3
And so far, everything is fine. The thing is, these two tables have many rows and I'd like to have result with dates, where cnt does not match.
In other words, I'd like to have something like this:
UserID | cnt | Date | UserID | cnt | Date
1 | 2 | 2018-05-01 | 1 | 3 | 2018-05-01
1 | 2 | 2018-05-02 | 1 | 3 | 2018-05-01
1 | 2 | NULL | 1 | 3 | 2018-05-03
The best soulution would be resultset where both cte's are joined to give this:
UserID | cnt | Date | UserID | cnt | Date
1 | 2 | 2018-05-01 | 1 | 3 | 2018-05-01
1 | 2 | 2018-05-02 | 1 | 3 | 2018-05-01
1 | 2 | NULL | 1 | 3 | 2018-05-03
1 | 2 | 2018-05-30 | 1 | 3 | NULL
You should do a FULL OUTER JOIN query like below
Select
C1.UserID,
C1.cnt,
C1.Date,
C2.UserID,
C2.cnt,
C2.Date
from
db1.Customer C1
FULL OUTER JOIN
db2.Customer C2
on C1.UserId=C2.UserId and C1.date=C2.Date
I have 02 tables Rubrique and BulletinRubrique
the table Rubrique contain the following columns :
ID int not null,
Name, varchar(max) not null,
RubriqueA_ID int null,
RubriqueB_ID int null
with data for example :
+-------+---------+--------------+--------------+
| ID | Name | RubriqueA_ID | RubriqueB_ID |
+-------+---------+--------------+--------------+
| 1 | R1 | 2 | 3 |
| 2 | R2 | 1 | 2 |
| 3 | R3 | NULL | NULL |
| 4 | R4 | NULL | 6 |
| 5 | R5 | 6 | NULL |
| 6 | R6 | NULL | 1 |
+-------+---------+--------------+--------------+
the two columns RubriqueA_ID, RubriqueB_ID are the foreigns Keys for the same table Rubrique (self-referencing) and they might be NULL
For the table BulletinRubrique :
ID int not null,
EmployeID int not null,
RubriqueID int not null,
Value float not null
with data :
+-------+-----------+--------------+------------+
| ID | EmployeID | Rubrique_ID | Value |
+-------+-----------+--------------+------------+
| B1 | EMP1 | 1 | 150 |
| B1 | EMP1 | 2 | 220 |
| B1 | EMP1 | 3 | 195 |
| B1 | EMP1 | 4 | 170 |
| B1 | EMP1 | 5 | 320 |
| B1 | EMP1 | 6 | 745 |
+-------+-----------+--------------+------------+
What I am trying to do is bulding the sql query to get result as :
+-------+-----------+--------------+------------+----------+---------+
| ID | EmployeID | Rubrique_ID | Value | A_Value | B_Value |
+-------+-----------+--------------+------------+----------+---------+
| B1 | EMP1 | 1 | 150 | 220 | 195 |
| B1 | EMP1 | 2 | 220 | 150 | 220 |
| B1 | EMP1 | 3 | 195 | NULL | NULL |
| B1 | EMP1 | 4 | 170 | NULL | 745 |
| B1 | EMP1 | 5 | 320 | 745 | NULL |
| B1 | EMP1 | 6 | 745 | NULL | 150 |
+-------+-----------+--------------+------------+----------+---------+
Please help me to build this query and thanks
http://rextester.com/FIJE42564 is the working code
SELECT t2.ID, t2.EmployeID, t2.RubriqueID, t2.Value, t2.A_Value, r2.Value AS B_value FROM BulletinRubrique r2
RIGHT JOIN
(
SELECT t1.ID, t1.EmployeID, t1.RubriqueID, t1.Value, r1.VALUE AS A_VALUE, t1.B_VALUE FROM BulletinRubrique r1
RIGHT JOIN (
SELECT b.ID, b.EmployeID,b.RubriqueID, b.Value, r.RubriqueA_ID AS A_Value, r.RubriqueB_ID AS B_Value
FROM BulletinRubrique b RIGHT JOIN Rubrique r ON r.ID = b.RubriqueID ) t1
ON t1.A_Value = r1.RubriqueID
)t2
ON t2.B_Value = r2.RubriqueID
ORDER BY t2.RubriqueID
Being a fan of nested CTE, this is the way I tried solving this
WITH CTE1 as(
SELECT
BR.Id, BR.EmployeID, BR.RubriqueID, BR.value, R1.Rubriquea_Id, R2.Rubriqueb_Id
FROM
BulletinRubrique BR
LEFT JOIN
Rubrique R1 ON R1.Id = BR.RubriqueID
LEFT JOIN
Rubrique R2 ON R2.Id = BR.RubriqueID
),
CTE2 as (
SELECT
C1.Id, C1.EmployeID, C1.RubriqueID, C1.value, C2.value as A_Value, C3.value as B_Value
FROM
CTE1 C1
LEFT JOIN
CTE1 C2 ON C1.Rubriquea_Id = C2.RubriqueID
LEFT JOIN
CTE1 C3 ON C1.RubriqueB_Id = C3.RubriqueID
)
SELECT C1.Id,
C1.EmployeID,
C1.RubriqueID,
C1.value,
C1.A_Value as A_Value,
C1.B_Value as B_Value FROM CTE2 C1
ORDER BY Id
I made a INNER JOIN in stored procedure, but I don't know what to put to my WHERE clause to filter those column with null values and only shows those rows who has not null on a particular column.
CREATE PROCEDURE [dbo].[25]
#param1 int
AS
SELECT c.Name, c.Age, c2.Name, c2.Country
FROM Cus C
INNER JOIN Cus2 C2 ON c.id = c2.id
WHERE c2.country is not null and c2.id = #param1
Order by c2.Country
RETURN 0
ID 1
+-----+----+---------+---------+
| QID | ID | Name | Country |
+-----+----+---------+---------+
| 1 | 1 | Null | PH |
| 2 | 1 | Null | CN |
| 3 | 1 | Japhet | USA |
| 4 | 1 | Abegail | UK |
| 5 | 1 | Norlee | Ger |
+-----+----+---------+---------+
ID 2
+-----+----+----------+---------+
| QID | ID | Name | Country |
+-----+----+----------+---------+
| 1 | 2 | Null | PH |
| 2 | 2 | Null | CN |
| 3 | 2 | Reynaldo | USA |
| 4 | 2 | Abegail | UK |
| 5 | 2 | Norlee | Ger |
+-----+----+----------+---------+
ID 3
+-----+----+----------+---------+
| QID | ID | Name | Country |
+-----+----+----------+---------+
| 1 | 3 | Gab | PH |
| 2 | 3 | Null | CN |
| 3 | 3 | Reynaldo | USA |
| 4 | 3 | Abegail | UK |
| 5 | 3 | Norlee | Ger |
+-----+----+----------+---------+
I want when I choose any of the user in the C Table it will display the C child table data and remove the null name rows and remain the rows with not null name column.
Desired Result:
C Table (Parent)
+----+---------+-----+
| ID | Name | Age |
+----+---------+-----+
| 3 | Abegail | 31 |
+----+---------+-----+
C2 Table (Child)
+-----+----+----------+---------+
| QID | ID | Name | Country |
+-----+----+----------+---------+
| 1 | 3 | Gab | PH |
| 3 | 3 | Reynaldo | USA |
| 4 | 3 | Abegail | UK |
| 5 | 3 | Norlee | Ger |
+-----+----+----------+---------+
WHERE column IS NOT NULL is the syntax to filter out NULL values.
Solution 1: test not null value
Example:
WHERE yourcolumn IS NOT NULL
Solution 2: test comparaison value in your where clause (comparaison substract null values)
Examples:
WHERE yourcolumn = value
WHERE yourcolumn <> value
WHERE yourcolumn in ( value)
WHERE yourcolumn not in ( value)
WHERE yourcolumn between value1 and value2
WHERE yourcolumn not between value1 and value2
MASTER TABLE
x------x--------------------x
| Id | Name |
x------x--------------------x
| 1 | A |
| 2 | B |
| 3 | C |
x------x--------------------x
DETAILS TABLE
x------x--------------------x-------x
| Id | PERIOD | QTY |
x------x--------------------x-------x
| 1 | 2014-01-13 | 10 |
| 1 | 2014-01-11 | 15 |
| 1 | 2014-01-12 | 20 |
| 2 | 2014-01-06 | 30 |
| 2 | 2014-01-08 | 40 |
x------x--------------------x-------x
I am getting the same results when LEFT JOIN and OUTER APPLY is used.
LEFT JOIN
SELECT T1.ID,T1.NAME,T2.PERIOD,T2.QTY
FROM MASTER T1
LEFT JOIN DETAILS T2 ON T1.ID=T2.ID
OUTER APPLY
SELECT T1.ID,T1.NAME,TAB.PERIOD,TAB.QTY
FROM MASTER T1
OUTER APPLY
(
SELECT ID,PERIOD,QTY
FROM DETAILS T2
WHERE T1.ID=T2.ID
)TAB
Where should I use LEFT JOIN AND where should I use OUTER APPLY
A LEFT JOIN should be replaced with OUTER APPLY in the following situations.
1. If we want to join two tables based on TOP n results
Consider if we need to select Id and Name from Master and last two dates for each Id from Details table.
SELECT M.ID,M.NAME,D.PERIOD,D.QTY
FROM MASTER M
LEFT JOIN
(
SELECT TOP 2 ID, PERIOD,QTY
FROM DETAILS D
ORDER BY CAST(PERIOD AS DATE)DESC
)D
ON M.ID=D.ID
which forms the following result
x------x---------x--------------x-------x
| Id | Name | PERIOD | QTY |
x------x---------x--------------x-------x
| 1 | A | 2014-01-13 | 10 |
| 1 | A | 2014-01-12 | 20 |
| 2 | B | NULL | NULL |
| 3 | C | NULL | NULL |
x------x---------x--------------x-------x
This will bring wrong results ie, it will bring only latest two dates data from Details table irrespective of Id even though we join with Id. So the proper solution is using OUTER APPLY.
SELECT M.ID,M.NAME,D.PERIOD,D.QTY
FROM MASTER M
OUTER APPLY
(
SELECT TOP 2 ID, PERIOD,QTY
FROM DETAILS D
WHERE M.ID=D.ID
ORDER BY CAST(PERIOD AS DATE)DESC
)D
Here is the working : In LEFT JOIN , TOP 2 dates will be joined to the MASTER only after executing the query inside derived table D. In OUTER APPLY, it uses joining WHERE M.ID=D.ID inside the OUTER APPLY, so that each ID in Master will be joined with TOP 2 dates which will bring the following result.
x------x---------x--------------x-------x
| Id | Name | PERIOD | QTY |
x------x---------x--------------x-------x
| 1 | A | 2014-01-13 | 10 |
| 1 | A | 2014-01-12 | 20 |
| 2 | B | 2014-01-08 | 40 |
| 2 | B | 2014-01-06 | 30 |
| 3 | C | NULL | NULL |
x------x---------x--------------x-------x
2. When we need LEFT JOIN functionality using functions.
OUTER APPLY can be used as a replacement with LEFT JOIN when we need to get result from Master table and a function.
SELECT M.ID,M.NAME,C.PERIOD,C.QTY
FROM MASTER M
OUTER APPLY dbo.FnGetQty(M.ID) C
And the function goes here.
CREATE FUNCTION FnGetQty
(
#Id INT
)
RETURNS TABLE
AS
RETURN
(
SELECT ID,PERIOD,QTY
FROM DETAILS
WHERE ID=#Id
)
which generated the following result
x------x---------x--------------x-------x
| Id | Name | PERIOD | QTY |
x------x---------x--------------x-------x
| 1 | A | 2014-01-13 | 10 |
| 1 | A | 2014-01-11 | 15 |
| 1 | A | 2014-01-12 | 20 |
| 2 | B | 2014-01-06 | 30 |
| 2 | B | 2014-01-08 | 40 |
| 3 | C | NULL | NULL |
x------x---------x--------------x-------x
3. Retain NULL values when unpivoting
Consider you have the below table
x------x-------------x--------------x
| Id | FROMDATE | TODATE |
x------x-------------x--------------x
| 1 | 2014-01-11 | 2014-01-13 |
| 1 | 2014-02-23 | 2014-02-27 |
| 2 | 2014-05-06 | 2014-05-30 |
| 3 | NULL | NULL |
x------x-------------x--------------x
When you use UNPIVOT to bring FROMDATE AND TODATE to one column, it will eliminate NULL values by default.
SELECT ID,DATES
FROM MYTABLE
UNPIVOT (DATES FOR COLS IN (FROMDATE,TODATE)) P
which generates the below result. Note that we have missed the record of Id number 3
x------x-------------x
| Id | DATES |
x------x-------------x
| 1 | 2014-01-11 |
| 1 | 2014-01-13 |
| 1 | 2014-02-23 |
| 1 | 2014-02-27 |
| 2 | 2014-05-06 |
| 2 | 2014-05-30 |
x------x-------------x
In such cases an APPLY can be used(either CROSS APPLY or OUTER APPLY, which is interchangeable).
SELECT DISTINCT ID,DATES
FROM MYTABLE
OUTER APPLY(VALUES (FROMDATE),(TODATE))
COLUMNNAMES(DATES)
which forms the following result and retains Id where its value is 3
x------x-------------x
| Id | DATES |
x------x-------------x
| 1 | 2014-01-11 |
| 1 | 2014-01-13 |
| 1 | 2014-02-23 |
| 1 | 2014-02-27 |
| 2 | 2014-05-06 |
| 2 | 2014-05-30 |
| 3 | NULL |
x------x-------------x
In your example queries the results are indeed the same.
But OUTER APPLY can do more: For each outer row you can produce an arbitrary inner result set. For example you can join the TOP 1 ORDER BY ... row. A LEFT JOIN can't do that.
The computation of the inner result set can reference outer columns (like your example did).
OUTER APPLY is strictly more powerful than LEFT JOIN. This is easy to see because each LEFT JOIN can be rewritten to an OUTER APPLY just like you did. It's syntax is more verbose, though.