Solved

sql query select on two criteria, same field?

Posted on 2009-07-02
16
1,170 Views
Last Modified: 2013-12-07
I want an sql SELECT that will select on the same field
and will use two, separate criteria for that field.

The result should be the subset that satisfies BOTH criteria.

The example below does not work.

How do I do this?


select * from cam where cust='1' and cust='2'

Open in new window

0
Comment
Question by:pillmill
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 4
  • 2
  • +4
16 Comments
 
LVL 75

Expert Comment

by:Aneesh Retnakaran
ID: 24765190
select * from cam where cust='1' or  cust='2'
0
 
LVL 75

Expert Comment

by:Aneesh Retnakaran
ID: 24765196
you never can 1 = 2
0
 
LVL 40

Expert Comment

by:mrjoltcola
ID: 24765204
You can also use IN()

where cust in('1', '2')
0
What Is Transaction Monitoring and who needs it?

Synthetic Transaction Monitoring that you need for the day to day, which ensures your business website keeps running optimally, and that there is no downtime to impact your customer experience.

 

Author Comment

by:pillmill
ID: 24765716
Thanks. Both where cust in('1', '2')  and  select * from cam where cust='1' or  cust='2'  are producing the WRONG result.

I want the intersection of the sets of results produced by these two queries:

1. select * from cam where cust='1'

2. select * from cam where cust='2'
0
 
LVL 45

Expert Comment

by:Kent Olsen
ID: 24765759
Hi pillmill,

The intersection will be a NULL set.  "cust" can be 1, or it can be 2, but it can't be both.


Kent
0
 

Author Comment

by:pillmill
ID: 24765896
Thanks. Here are the records:

table cam:

cust     cama
1          a
1           b
2          a
2          c


I want the query to return the value "a" .  The value "a" is the one
which is the same between cust 1 and 2.
0
 
LVL 45

Expert Comment

by:Kent Olsen
ID: 24766043

Hmm....  There are a lot of variables here.  Can 'a occur more than once per customer number?  Will it occur only twice?  Are more values than 1 and 2 possible for cust, etc.

Here's one solution:

SELECT cama, count() as c FROM mytable
GROUP BY cama
HAVING c > 1;


Kent
0
 
LVL 11

Expert Comment

by:Andytw
ID: 24766127
Try:
SELECT cama FROM cam WHERE cust = 1
INTERSECT
SELECT cama FROM cam WHERE cust = 2;
 
or
 
SELECT cama c1
FROM cam WHERE cust = 1
WHERE EXISTS ( SELECT NULL
               FROM cam c2
               WHERE c1.cama = c2.cama
                 AND c1.cust <> c2.cust )
  

Open in new window

0
 
LVL 32

Expert Comment

by:awking00
ID: 24766220
I suspect your problem may be little more complex than that indicated by your example. Are you trying to find values that exist for more than one customer, that exist for every customer, or do you want entire records (or perhaps more than one field) where those instances occur? Perhaps you could post some more relevant sample data and what your expected output should be.
0
 

Author Comment

by:pillmill
ID: 24766678
SELECT cama c1
FROM cam WHERE cust = 1
WHERE EXISTS ( SELECT NULL
               FROM cam c2
               WHERE c1.cama = c2.cama
                 AND c1.cust <> c2.cust )

produces a MySQL error:

Error Code : 1064
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE exists ( SELECT NULL
0
 

Author Comment

by:pillmill
ID: 24766712
Record "a" is the common element.  

0
 
LVL 32

Expert Comment

by:awking00
ID: 24766861
Change "where exists" to "and exists".
0
 
LVL 45

Accepted Solution

by:
Kent Olsen earned 500 total points
ID: 24766880
Hi Pill,

In this simple example, the cleanest SQL is an inner join.

SELECT cama
FROM mytable t0, mytable t1
WHERE t0.cama = t1.cama
  AND t0.cust = 1
  AND t0.cust = 2;

But that's probably not a lot of use with a larger data set.  Still, let's see where this goes.  :)


Kent
0
 
LVL 2

Expert Comment

by:kbac
ID: 24771030
select * from cam where
cama in (select cama from cam where cust='1' )
and
cama in (select cama from cam where cust='2' )
0
 

Author Closing Comment

by:pillmill
ID: 31599269
Thanks!
0
 
LVL 45

Expert Comment

by:Kent Olsen
ID: 24861181
Hi Pill,

For the record, there was a typo in my SQL, but it looks like you figured that out.   :)

Kent
0

Featured Post

Simplifying Server Workload Migrations

This use case outlines the migration challenges that organizations face and how the Acronis AnyData Engine supports physical-to-physical (P2P), physical-to-virtual (P2V), virtual to physical (V2P), and cross-virtual (V2V) migration scenarios to address these challenges.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

When table data gets too large to manage or queries take too long to execute the solution is often to buy bigger hardware or assign more CPUs and memory resources to the machine to solve the problem. However, the best, cheapest and most effective so…
Containers like Docker and Rocket are getting more popular every day. In my conversations with customers, they consistently ask what containers are and how they can use them in their environment. If you’re as curious as most people, read on. . .
This video shows how to recover a database from a user managed backup
This video explains what a user managed backup is and shows how to take one, providing a couple of simple example scripts.

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question