Help needed in SQL query

[b4babu]

Hi,

I've a table named PC as below:
PC(code, model, speed, ram, hd, cd, price) I want to write a query to find the pairs of PC models having similar speeds and RAM. Also, in the result set, the pairs of PC's being compared should occur only once, i.e, if (i,j) is compared then (j,i) shouldn't be compared. Plz help me solve this query.

Thanks,
Babu

[rushdishams]

dear mate, it is fair to show some of what you have done and what you have got so that you are needing help... with no offence, else it just looks like many of us are doing your homeworks where you are not putting effort at all. ok?

SELECT DISTINCT(p.model), p.speed, p.ram 
FROM pc p, pc q 
WHERE p.speed=q.speed AND p.ram=q.ram AND p.model!=q.model
ORDER BY p.model;
 

hope that helps you...

cheers mate!

[ptpa365]

SELECT DISTINCT p.model,,q.mode l, p.speed, p.ram
FROM pc p, pc q
WHERE p.speed=q.speed AND p.ram=q.ram AND p.model!=q.mode l
ORDER BY p.model;

Hi,

I've a table named PC as below:
PC(code, model, speed, ram, hd, cd, price) I want to write a query to find the pairs of PC models having similar speeds and RAM. Also, in the result set, the pairs of PC's being compared should occur only once, i.e, if (i,j) is compared then (j,i) shouldn't be compared. Plz help me solve this query.

Thanks,
Babu

[debasisdas]

SELECT DISTINCT T1.model,,T2.model, T1.speed, T1.ram 
FROM pc T1, pc T2 
WHERE T1.speed=T2.speed AND T1.ram=T2.ram AND T1.model<>T2.model
ORDER BY T1.model;
 

since in this case we use 2 alias for the same table and join both the tables this is the example of SELF JOIN (join of a table with itself)

Hope that helps u