I'm trying to do with following with an SQL query in Impala. I've got a single data table that has (among other things) two columns with values that intersect multiple times. For example, let's say we have a table with two columns for related names and phone numbers:
Names Phone Numbers
John Smith (123) 456-7890
Rob Johnson (123) 456-7890
Greg Jackson (123) 456-7890
Tom Green (123) 456-7890
Jack Mathis (123) 456-7890
John Smith (234) 567-8901
Rob Johnson (234) 567-8901
Joe Wolf (234) 567-8901
Mike Thomas (234) 567-8901
Jim Moore (234) 567-8901
John Smith (345) 678-9012
Rob Johnson (345) 678-9012
Toby Ellis (345) 678-9012
Sam Wharton (345) 678-9012
Bob Thompson (345) 678-9012
John Smith (456) 789-0123
Rob Johnson (456) 789-0123
Kelly Howe (456) 789-0123
Hank Rehms (456) 789-0123
Jim Fellows (456) 789-0123
What I need to get from this table is a selection of each item from the Name column that has multiple entries from the Phone Numbers column associated with it, like this:
Names Phone Numbers
John Smith (123) 456-7890
John Smith (234) 567-8901
John Smith (345) 678-9012
John Smith (456) 789-0123
Rob Johnson (123) 456-7890
Rob Johnson (234) 567-8901
Rob Johnson (345) 678-9012
Rob Johnson (456) 789-0123
This is the query I've got so far, but it's not quite giving me the results I'm looking for:
SELECT a.name, a.phone_number, b.phone_number, b.count1
FROM databasename a
INNER JOIN (
SELECT phone_number, COUNT(phone_number) as count1
FROM databasename
GROUP BY phone_number
) b
ON a.phone_number = b.phone_number;
Any ideas on how to improve my query to get the results I'm looking for?
Thank you.
Working with your query...
This generates a subset by name of users having more than 1 phone number it then joins back to the entire set based on name returning all phone numbers for users having more than 1 phone number. however if a user has the same phone number listed more than once it would get returned. to eliminate those if needed, add distinct to the count in the inline view.
SELECT a.name, a.phone_number
FROM databasename a
INNER JOIN (
SELECT name, COUNT(phone_number) as count1
FROM databasename
GROUP BY name
having COUNT(phone_number) > 1
) b
on a.name = b.name
Order by a.name, a.phone_Number
One method is to use exists:
select t.*
from tablename t
where exists (select 1 from tablename t2 where t2.name = t.name and t2.phonenumber <> t.phonenumber)
SELECT DISTINCT x.*
FROM my_table x
JOIN my_table y
ON y.name = x.name
AND y.phone <> x.phone;
Related
I am trying to join two tables based on one column from one table and two column from other table
Table a
name, designation
Mr. james john, manager
Mr. jim james, tester
Mr. abe james, developer
Table b
first name, last name, emp id
james,john,1
jim, james,2
abe,james,3
I want to join table a name column with table b combining "Mr. "+first name+last name.
Here's a way to do what your question asks:
res = a.join(b.assign(name='Mr. ' + b['first name'] + ' ' + b['last name']).set_index('name'), on='name')
Input:
dataframe a:
name designation
0 Mr. james john manager
1 Mr. jim james tester
2 Mr. abe james developer
dataframe b:
first name last name emp id
0 james john 1
1 jim james 2
2 abe james 3
Output:
name designation first name last name emp id
0 Mr. james john manager james john 1
1 Mr. jim james tester jim james 2
2 Mr. abe james developer abe james 3
For an auditing project, need to select at random three tracking IDs per associate and cannot be dups. Wondering if it's possible with SQL?
Sample SQL Server Data:
Associate
Tracking ID
Smith, Mary
TRK65152
Smith, Mary
TRK74183
Smith, Mary
TRK35154
Smith, Mary
TRK23117
Smith, Mary
TRK11889
Jones, Walter
TRK17364
Jones, Walter
TRK91736
Jones, Walter
TRK88234
Jones, Walter
TRK80012
Jones, Walter
TRK55874
Williams, Tony
TRK58142
Williams, Tony
TRK47336
Williams, Tony
TRK13254
Williams, Tony
TRK28596
Williams, Tony
TRK33371
You may use ROW_NUMBER here with a random ordering:
WITH cte AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY Associate ORDER BY NEWID()) rn
FROM yourTable
)
SELECT Associate, TrackingID
FROM cte
WHERE rn <= 3;
My first time reading a question on here.
I am working at a university and I have a table of student IDs and their supervisors, some of the students have one supervisor and some have two or three depending on their subject.
The table looks like this
ID Supervisor
1 John Doe
2 Peter Jones
2 Sarah Jones
3 Peter Jones
3 Sarah Jones
4 Stephen Davies
4 Peter Jones
4 Sarah Jones
5 John Doe
I want to create a view that turns that into this:
ID Supervisor 1 Supervisor 2 Supervisor 3
1 John Doe
2 Peter Jones Sarah Jones
3 Peter Jones Sarah Jones
4 Stephen Davies Peter Jones Sarah Jones
5 John Doe
I have looked at PIVOT functions, but don't think it matches my needs.
Any help is greatly appreciated.
PIVOT was the right clue, it only needs a little 'extra' :)
DECLARE #tt TABLE (ID INT,Supervisor VARCHAR(128));
INSERT INTO #tt(ID,Supervisor)
VALUES
(1,'John Doe'),
(2,'Peter Jones'),
(2,'Sarah Jones'),
(3,'Peter Jones'),
(3,'Sarah Jones'),
(4,'Stephen Davies'),
(4,'Peter Jones'),
(4,'Sarah Jones'),
(5,'John Doe');
SELECT
*
FROM
(
SELECT
ID,
'Supervisor ' + CAST(ROW_NUMBER() OVER(PARTITION BY ID ORDER BY Supervisor) AS VARCHAR(128)) AS supervisor_id,
Supervisor
FROM
#tt
) AS tt
PIVOT(
MAX(Supervisor) FOR
supervisor_id IN ([Supervisor 1],[Supervisor 2],[Supervisor 3])
) AS piv;
Result:
ID Supervisor 1 Supervisor 2 Supervisor 3
1 John Doe NULL NULL
2 Peter Jones Sarah Jones NULL
3 Peter Jones Sarah Jones NULL
4 Peter Jones Sarah Jones Stephen Davies
5 John Doe NULL NULL
You will notice that the assignment to Supervisor X is done by ordering by the Supervisor-VARCHAR. If you want the ordering done differently, you might want to include an [Ordering] column; then change to ROW_NUMBER() OVER(PARTITION BY ID ORDER BY [Ordering]). Eg an [Ordering] column could be an INT IDENTITY(1,1). I'll leave that as an excercise to you if that's what's really needed.
I'm having an issue with a complex query on an SQLite3 database that I think has to do with a misunderstanding on my part of how to refer to columns in a results table returned by a select statement, especially when aliases are involved.
Here is an example table - a list of movie IDs with a row for each actor working on the movie:
CREATE TABLE movie_actor (imdb_id TEXT, actor TEXT);
INSERT INTO movie_actor VALUES('44r4', 'John Doe');
INSERT INTO movie_actor VALUES('44r4', 'Jane Doe');
INSERT INTO movie_actor VALUES('44r4', 'Jermaine Doe');
INSERT INTO movie_actor VALUES('44r4', 'Jacob Doe');
INSERT INTO movie_actor VALUES('55r5', 'John Doe');
INSERT INTO movie_actor VALUES('55r5', 'Jane Doe');
INSERT INTO movie_actor VALUES('55r5', 'Nathan Deer');
INSERT INTO movie_actor VALUES('66r6', 'Bob Duck');
INSERT INTO movie_actor VALUES('66r6', 'John Doe');
INSERT INTO movie_actor VALUES('66r6', 'Jermaine Doe');
INSERT INTO movie_actor VALUES('66r6', 'Jane Doe');
INSERT INTO movie_actor VALUES('77r7', 'John Doe');
I am trying to find out the how many times each pair of actors worked with each other across all movies. I decided to go about this with a self-join, but ran into issues where I would get record pairs such as "John Doe, Jane Doe, 3" and "Jane Doe, John Doe, 3" - this is really the same thing, and I wanted to only count the first version. This is the code that resulted:
SELECT DISTINCT
CASE WHEN d.actor_1 > d.actor_2 THEN d.actor_1 ELSE d.actor_2 END d.actor_1,
CASE WHEN d.actor_2 > d.actor_1 THEN d.actor_2 ELSE d.actor_1 END d.actor_2,
d.v
FROM (
SELECT c.actor_1 AS actor_1, c.actor_2 AS actor_2, COUNT(*) AS v
FROM (
SELECT a.actor AS actor_1, b.actor AS actor_2
FROM movie_actor a JOIN movie_actor b ON a.imdb_id=b.imdb_id
) AS c
WHERE c.actor_1 <> c.actor_2
GROUP BY c.actor_1, c.actor_2
HAVING COUNT(*) > 2
ORDER BY COUNT(*) DESC
LIMIT 20
)
AS d
This doesn't run, but I can't figure out why. My assumption is that I am not using aliases properly, but I really don't know. Any ideas?
(SQL Fiddle link here)
We get a simpler query, if we add the condition a.actor < b.actor. This excludes pairs with equal actors and at the same time it removed the need of swapping actors.
SELECT
a.actor AS actor_1, b.actor AS actor_2, COUNT(*) AS v
FROM
movie_actor a
INNER JOIN movie_actor b
ON a.imdb_id = b.imdb_id
WHERE
a.actor < b.actor
GROUP BY a.actor, b.actor
ORDER BY COUNT(*) DESC, a.actor, b.actor
LIMIT 20
Note: SQL always creates a cross product when joining, i.e. it creates all possible combinations of records that match the join condition. Therefore for imdb 55r5 (including 3 actors) it will first generate the following 3 x 3 = 9 pairs:
John Doe John Doe
John Doe Jane Doe
John Doe Nathan Deer
Jane Doe John Doe
Jane Doe Jane Doe
Jane Doe Nathan Deer
Nathan Deer John Doe
Nathan Deer Jane Doe
Nathan Deer Nathan Deer
Then the WHERE-clause excludes all a >= b pairs and we get
John Doe Nathan Deer
Jane Doe John Doe
Jane Doe Nathan Deer
Generate the distinct pairs first, then count them.
select actor_1, actor_2, count(*)
from (select distinct a.imdb_id, a.actor as actor_1, b.actor as actor_2
from movie_actor a
inner join movie_actor b on a.imdb_id = b.imdb_id
where a.actor < b.actor) x
group by actor_1, actor_2
order by actor_1, actor_2;
actor_1 actor_2 count(*)
---------- ---------- ----------
Bob Duck Jane Doe 1
Bob Duck Jermaine D 1
Bob Duck John Doe 1
Jacob Doe Jane Doe 1
Jacob Doe Jermaine D 1
Jacob Doe John Doe 1
Jane Doe Jermaine D 2
Jane Doe John Doe 3
Jane Doe Nathan Dee 1
Jermaine D John Doe 2
John Doe Nathan Dee 1
I have a table which contains names:
Name
----
John Smith
John Smith
Sam Wood
George Wright
John Smith
Sam Wood
I want to create a select statement which shows this:
Name
'John Smith 1'
'John Smith 2'
'Sam Wood 1'
'George Wright 1'
'John Smith 3'
'Sam Wood 2'
In other words, I want to add separate counters to each name. Is there a way to do it without using cursors?
Use ROW_NUMBER():
SELECT Name, ROW_NUMBER() OVER(Partition BY Name ORDER BY Name) as [Rank]
FROM MyTable
Doing:
select name, count(*) as total from table group by name;
will get you something that looks like this:
name | total
-------------+------------
John Smith | 2
-------------+------------
Sam Wood | 2
-------------+------------
George Wright| 1
This isn't what you really wanted though - ROW_NUMBER(), as ck pointed out, is what you want, but not all databases support it - mysql doesn't, for example. If you're using MySQL, this might help:
ROW_NUMBER() in MySQL