I have the following tables:
Students
StudentID UserID FirstName LastName
1 1 John Doe
2 3 Peter Pan
3 5 Mark Twain
Employees
EmployeeID UserID FirstName LastName
1 2 Juan Carlos
2 4 Joe Reyes
3 6 Ash Ketchum
Users
UserID Username
1 test1
2 test2
3 test3
4 test4
5 test5
6 test6
Messages
MessageID MessageFrom MessageTo Subject
1 1 2 test message
2 4 3 another test message
3 3 5 another test message
I want to display the output like this
MessageID MessageFrom MessageTo Subject
1 John Doe Juan Carlos test message
2 Joe Reyes Peter Pan another test message
3 Peter Pan Mark Twain another test message
Where MessageFrom and MessageTo returns a foreign key value from UserID located from the Users table. Students can send messages to the employees, and vice-versa. They can also send between students and employees.
I think this is The X Y Problem again.
Why did you split your Users in two parts ?
Why not making it like this (which would solve the whole problem) :
UserID | FirstName | LastName | UserName | Type
-------------------------------------------------------
1 John Doe test1 1
2 Juan Carlos test2 2
3 Mark Twain test3 1
And add a table Types
TypeId | TypeName
1 Students
2 Employees
This way you have 2 Tables for users instead of 3.
All users and names are in the same table as it should be.
This should do the trick, since you don't care if the message is related to a student or employee you can just union those 2 tables.
SELECT
MessageID,
(FromTable.FirstName + ' ' + FromTable.LastName) AS MessageFrom,
(ToTable.FristName + ' ' + ToTable.LastName) AS MessageTo,
Subject
FROM
Messages
INNER JOIN
(
(SELECT UserID, FirstName, LastName FROM Students)
UNION
(SELECT UserID, FirstName, LastName FROM Employees)
) AS FromTable ON FromTable.UserID = Messages.MessageFrom
INNER JOIN
(
(SELECT UserID, FirstName, LastName FROM Students)
UNION
(SELECT UserID, FirstName, LastName FROM Employees)
) AS ToTable ON ToTable.UserID = Messages.MessageTo
Related
I have two tables
select * from elig
select * from elig1
in the same database.
Table 1
Firstname, Lastname, MemberNo
Table 2
Firstname, Lastname, MemeberNo
Table 1:
ash dassant 1
alex peters 2
john lex 3
kyle passant 4
file leters 5
zed luthr 6
Table 2:
a dassant 1
a peters 2
j lex 3
When I try to select the records from table 1 I get complete firstname and lastname
But when I try to select records from table 2 I get only the first letter of first name and complete lastname
Any help here would be appreciated if I can get the full first name for second table
I'm using SQL-Server 2008. How to take value from one column and pass It to another column?
As you see in sample data below there are 4 columns. Where I need to take column name (in this case UserName) and pass It to FieldName column and value from UserName column pass to Value column.
SAMPLE DATA
GroupId UserName FieldName Value
1 John Smith Foo 28
1 John Smith Bar 2
1 John Smith FooBar 11
1 John Smith Bizz 22
2 Peter Jones Foo 4
2 Peter Jones Bar 13
2 Peter Jones FooBar 27
2 Peter Jones Bizz 23
DESIRED RESULTS
GroupId FieldName Value
1 Foo 28
1 Bar 2
1 FooBar 11
1 Bizz 22
1 UserName John Smith
2 Foo 4
2 Bar 13
2 FooBar 27
2 Bizz 23
2 UserName Peter Jones
How could I achieve It? By using PIVOT? But I'm not sure how to merge pivoted data to existing column. Have you any ideas? If something unclear - ask me, I'll try provide more details.
select GroupId, FieldName, Value
from table
union
select distinct GroupId, 'username', UserName
from table
No need to PIVOT , just a simple UNION ALL will do the job :
SELECT DISTINCT t.groupID,'USERNAME',t.userName
FROM YourTable t
UNION ALL
SELECT s.groupID,s.FieldName,s.Value
FROM YourTable s
SELECT DISTINCT t.*
FROM tbl
CROSS APPLY (
VALUES
(GroupId, FieldName, Value),
(GroupId, 'UserName', UserName)
) t(GroupId, FieldName, Value)
Also check a small information about UNPIVOT and VALUES from my post
I am working with duplicating multiple records in table 1 with primary key which has a reference with table 2 (foreign key)
Consider table employee with columns (eid(primary key),ename,dept,dept_code).
Table 2 employee_address with columns (eaid(primary key), eid(foreign key), city, country)
Now the task is the table 1 (ie. employee) may have number of values with different department codes.
Suppose dept_code may be 1 or 2 like so and so.
Now with both the table with some data look like this
EMPLOYEE table
Eid(pk) ename dept Dept_code
100 Sss Cse 1
101 Aaa Cse 1
102 Bbb Cse 1
103 Ccc Eee 2
104 ddd it 3
EMPLOYEE ADDRESS table
Eaid (pk) Eid (fk) city country
1 100 NY Us
2 100 NY Us
3 100 NY Us
4 101 CALIF Us
5 102 DC Us
6 102 DC Us
7 103 NJ Us
now the thing is i have to duplicate all the records in employee table where dept_code=1 and duplicate records dept_code should be = 5.
And the foreign key referencing to employee address table (ie. here in the current document 100,101,102) in the table 2 has to be duplicated number of times those foreign key value present in table 2.
I have to get the output like this
Employee table
Eid(pk) ename dept Dept_code
100 Sss Cse 1
101 Aaa Cse 1
102 Bbb Cse 1
103 Ccc Eee 2
104 ddd it 3
**105 sss cse 5
106 aaa cse 5
107 bbb cse 5**
Employee Address table
Eaid (pk) Eid (fk) city country
1 100 NY Us
2 100 NY Us
3 100 NY Us
4 101 CALIF Us
5 102 DC Us
6 102 DC Us
7 103 NJ Us
**8 105 NY Us
9 105 NY Us
10 105 Ny Us
11 106 CALIF Us
12 107 DC Us
13 107 DC Us**
Now I have to get the output like this.
Conditions for this task is,
no for loop
hitting a database should be as minimal as possible
can use java or if posssible in sql query itself.
I tried with various ideas nothing worked out.
Help me out in this.
If I understand your question, these two queries will work. They use tSql window functions, if you are not using Sql Server then you will need to find the equivalent.
Edited to answer comment from OP-
If you want to create new tables:
Select * Into EmployeeNew From (
Select *
From Employee E
Union All
Select Row_Number() Over (Order By eid) + (Select Max(eid) From Employee),
ename, dept, 5 dept_code
From Employee
Where Dept_Code = 1) A
Select * Into EmployeeAddressNew From (
Select A.*
From Employee E
Join EmployeeAddress A On A.eid = E.eid
Union All
Select A.eaid + (Select Max(eaid) From EmployeeAddress),
Dense_Rank() Over (Order By E.eid) + (Select Max(eid) From Employee),
City, Country
From Employee E
Join EmployeeAddress A On A.eid = E.eid
Where E.Dept_Code = 1) A
If you only want to insert 'new' records into the original tables:
Insert Employee
Select Row_Number() Over (Order By eid) + (Select Max(eid) From Employee),
ename, dept, 5 dept_code
From Employee
Where Dept_Code = 1
Insert EmployeeAddress
Select A.eaid + (Select Max(eaid) From EmployeeAddress),
Dense_Rank() Over (Order By E.eid) + (Select Max(eid) From Employee),
City, Country
From Employee E
Join EmployeeAddress A On A.eid = E.eid
Where E.Dept_Code = 1
Suppose I have a table like below:
ID Name ManagerID
1 Dave NULL
2 Scott 1
3 Mike 1
4 Nick 3
5 Jack 1
How Can I find out corresponding Manager Name of all the employee, something like below format?
ID Name ManagerID ManagerName
1 Dave NULL NULL
2 Scott 1 Dave
3 Mike 1 Dave
4 Nick 3 Mike
5 Jack 1 Dave
Try this!
select a.ID,a.Name,a.ManagerID,b.Name as ManagerName
from #t a left join #t b on a.ManagerID=b.ID
Demo
select ID, Name, ManagerID,
(case when managerid is null then null else (select Name from tab where id=managerid) end) as ManagerName
from tab
You can do this way too
Possible in several ways.
Such as:
SELECT
ID, Name, ManagerID,
(SELECT Name FROM table AS ManagersTable WHERE ManagersTable.ID=EmployeesTable.ManagerID) AS ManagerName
FROM table AS EmployeesTable
I have got a table named student. I have written this query:
select * From student where sname in ('rajesh','rohit','rajesh')
In the above query it's returning me two records; one matching 'rajesh' and another matching: 'rohit'.
But i want there to be 3 records: 2 for 'rajesh' and 1 for 'rohit'.
Please provide me some solution or tell me where i am missing.
NOTE: the count of result of sub query is not fix there can be many words there some distinct and some multiple occurrence .
Thanks
Your requirements are not clear, and I'll try to explain why.
Let's define table students
ID FirstName LastName
1 John Smith
2 Mike Smith
3 Ben Bray
4 John Bray
5 John Smith
6 Bill Lynch
7 Bill Smith
Query with WHERE clause:
FirstName in ('Mike', 'Ben', 'Mike')
will return 2 rows only, because it could be rewritten as:
FirstName='Mike' or FirstName='Ben' or FirstName='Mike'
WHERE is filtering clause that just says if existing row satisfy given conditions or not (for each of rows created by FROM clause.
Let's say we have subquery that returns any number of non distinct FirstNames
In case if SQ contains 'Mike', 'Ben', 'Mike' using inner join you can get those 3 rows without problem
Select ST.* from Students ST
Inner Join (Select name from …. <your subquery>) SQ
On ST.FirstName=SQ.name
Result will be:
ID FirstName LastName
2 Mike Smith
2 Mike Smith
3 Ben Bray
Note data are not ordered by order of names returning by SQ. If you want that, SQ should return some ordering number, eg.:
Ord Name
1. Mike
2. Ben
3. Mike
In that case query should be:
Select ST.* from Students ST
Inner Join (Select ord, name from …. <your subquery>) SQ
On ST.FirstName=SQ.name
Order By SQ.ord
And result:
ID FirstName LastName
2 Mike Smith (1)
3 Ben Bray (2)
2 Mike Smith (3)
Now, let's se what will happen if subquery returns
Ord Name
1. Mike
2. Bill
3. Mike
You will end up with
ID FirstName LastName
2 Mike Smith (1)
6 Bill Lynch (2)
7 Bill Smith (2)
2 Mike Smith (3)
Even worse, if you have something like:
Ord Name
1. John
2. Bill
3. John
Result is:
ID FirstName LastName
1 John Smith (1)
4 John Bray (1)
5 John Smith (1)
6 Bill Lynch (2)
7 Bill Smith (2)
1 John Smith (3)
4 John Bray (3)
5 John Smith (3)
This is an complex situation, and you have to clarify precisely what requirement is.
If you need only one student with the same name, for each of rows in SQ, you can use something like SQL 2005+):
;With st1 as
(
Select Row_Number() over (Partition by SQ.ord Order By ID) as rowNum,
ST.ID,
ST.FirstName,
ST.LastName,
SQ.ord
from Students ST
Inner Join (Select ord, name from …. <your subquery>) SQ
On ST.FirstName=SQ.name
)
Select ID, FirstName, LastName
From st1
Where rowNum=1 -- that was missing row, added later
Order By ord
It will return (for SQ values John, Bill, John)
ID FirstName LastName
1 John Smith (1)
6 Bill Lynch (2)
1 John Smith (3)
Note, numbers (1),(2),(3) are shown to display value of ord although they are not returned by query.
If you can split the where clause in your calling code, you could perform a UNION ALL on each clause.
SELECT * FROM Student WHERE sname = 'rajesh'
UNION ALL SELECT * FROM Student WHERE sname = 'rohit'
UNION ALL SELECT * FROM Student WHERE sname = 'rajesh'
Try using a JOIN:
SELECT ...
FROM Student s
INNER JOIN (
SELECT 'rajesh' AS sname
UNION ALL
SELECT 'rohit'
UNION ALL
SELECT 'rajesh') t ON s.sname = t.sname
just because you've got a criteria in there two times doesn't mean that it will return 1 result per criteria. SQL engines usually just use the unique criteria - thus, from your example, there will be 2 criteria in IN clause: 'rajesh','rohit'
WHY do you need to return 2 results? are there two rajesh in your table? they should BOTH return then. You don't need to ask for rajesh twice for that to happen. What does your data look like? What do you want to see returned?
Hi i am query just as you give above and it give me all data that matches in the condition of in clause. just like your post
select * from person
where personid in (
'Carson','Kim','Carson'
)
order by FirstName
and its give me all records which fulfill this Criteria