SQL subquery or not? - sql

I am trying to find a query that will select from two tables but not join those two tables as I don't want the result on one line.
Lets say I have these tables:
Persons1 Persons2
Number Name Surname Number Name Surname
----------------------- -------------------------
1 Peter Miller 1 Frank Farian
2 Hans Geige 2 Thomas Müller
And when I use this query:
SELECT
NEW.NAME,
OLD.NAME
FROM
PERSONS1 NEW,
PERSONS2 OLD
WHERE
NEW.Number = 1 AND
OLD.Number = 1
I get the following result:
Peter Frank
How do I write the query to get:
Peter
Frank

Use UNION for this:
SELECT NEW.NAME
FROM PERSONS1 NEW
WHERE NEW.Number = 1
UNION
SELECT OLD.NAME
FROM PERSONS2 OLD
WHERE OLD.Number = 1

Related

Join two rows that contain a common column value [duplicate]

Let's say I've got the following database table
Name | Nickname | ID
----------------------
Joe Joey 14
Joe null 14
Now I want to do a select statement that merges these two columns to one while replacing the null values. The result should look like this:
Joe, Joey, 14
Which sql statement manages this (if it's even possible)?
Simplest solution:
SQL> select * from t69
2 /
NAME NICKNAME ID
---------- ---------- ----------
Joe Joey 14
Joe 14
Michael 15
Mick 15
Mickey 15
SQL> select max(name) as name
2 , max(nickname) as nickname
3 , id
4 from t69
5 group by id
6 /
NAME NICKNAME ID
---------- ---------- ----------
Joe Joey 14
Michael Mickey 15
SQL>
If you have 11gR2 you could use the new-fangled LISTAGG() function but otherwise it is simple enough to wrap the above statement in a SELECT which concatenates the NAME and NICKNAME columns.
AFAIK,
the question is not clear.so i am making some assumptions over here.
your output has the first and 3rd columns for both the rows as same.
Only the 2nd field is different.
so u can simply write a select quest
select one.name,two.nick_name,one.id from
(select name,id from your_tb group by name,id) one,
your_tb two
where two.nickname is not NULL
and two.name=one.name
and two.id=one.id;
may be we can tune this but i am not good in tuning sql squeries,but this is the way i suppose u need.

SQL Server table first name last name

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

SQL query to identify result using self join or any other way

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

Select query which returns exect no of rows as compare in values of sub query

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

Merging two rows to one while replacing null values

Let's say I've got the following database table
Name | Nickname | ID
----------------------
Joe Joey 14
Joe null 14
Now I want to do a select statement that merges these two columns to one while replacing the null values. The result should look like this:
Joe, Joey, 14
Which sql statement manages this (if it's even possible)?
Simplest solution:
SQL> select * from t69
2 /
NAME NICKNAME ID
---------- ---------- ----------
Joe Joey 14
Joe 14
Michael 15
Mick 15
Mickey 15
SQL> select max(name) as name
2 , max(nickname) as nickname
3 , id
4 from t69
5 group by id
6 /
NAME NICKNAME ID
---------- ---------- ----------
Joe Joey 14
Michael Mickey 15
SQL>
If you have 11gR2 you could use the new-fangled LISTAGG() function but otherwise it is simple enough to wrap the above statement in a SELECT which concatenates the NAME and NICKNAME columns.
AFAIK,
the question is not clear.so i am making some assumptions over here.
your output has the first and 3rd columns for both the rows as same.
Only the 2nd field is different.
so u can simply write a select quest
select one.name,two.nick_name,one.id from
(select name,id from your_tb group by name,id) one,
your_tb two
where two.nickname is not NULL
and two.name=one.name
and two.id=one.id;
may be we can tune this but i am not good in tuning sql squeries,but this is the way i suppose u need.