Retrieving values from two columns based on different conditions - sql

Question

I have a question for you all. I have 'inherited' a DB at work and I have to create a report from a table using different conditions. Please note I'm no sql expert, I hope what I write makes sense.
Trying to simplify, I have a HARDWARE table that contains the following:
HWTYPE - type of hardware
HWMODEL - model of hardware
PHONENUM - phone number
USERID - user the hardware is assigned to
the data looks like this:
HWTYPE | HWMODEL | PHONENUM | USERID
-------+------------+------------+----------
SIM | SIMVOICE | 123456 | CIRO
SIM | SIMVOICE | 124578 | LEO
PHONE | APPLE | | CIRO
PHONE | SAMSUNG | | LEO
now as you can see, every user has assigned one phone and one SIM with a phone number.
I need to sort the data per user, so that every line of the query result look like:
HW | PHONENUM | USERID
---------+--------------+------
APPLE | 123456 | CIRO
SAMSUNG | 124578 | LEO
so basically: group column PHONENUM and HWMODEL based on USER.
And this is where I get stuck! I tried union, join, case etc. but I still don't get the correct result.
Again apologies for the (probably) very basic question. I tried to look for something similar but could not find anything.
Thanks to whoever will want to help me.
regards
Leo

Answer 1

I dont know that I understood your question or not
But i think you just need to write following query for your O/P
SELECT
HWTYPE, HWMODEL, USERID
FROM
HARDWARE
GROUP BY USERID ,HWTYPE,HWMODEL
ORDER BY HWTYPE

Answer 2

Placing my comment as an answer;
Write this as your SQL:
SELECT
(HWTYPE, HWMODEL, USERID)
FROM
HARDWARE
GROUP BY (USERID) /*Other Clauses can be added here, but ensure you use commas to seperate them!*/
Taking this step by step:
SELECT ... -> what columns you want to see
FROM ... -> what table you want it from (use joins if you need from multiple tables)
GROUP BY... -> What you want to collect together
There is also:
WHERE... -> conditions for when to include/what not to include

Answer 3

You can also get your expected Result using below query. This will use self join on Hardware table as well as reduce the length of query syntex.
SELECT H2.HWMODEL AS HW,H1.PHONENUM,H1.USERID FROM HARDWARE H1 INNER JOIN HARDWARE H2 ON H1.USERID = H2.USERID
WHERE ISNULL(H1.PHONENUM,'') <> ''
AND ISNULL(H2.PHONENUM,'') = ''
ORDER BY H2.HWMODEL ASC
Hope this will help you.

Answer 4

If your goal is a list of Phone numbers and models sorted by user, you can use this query:
SELECT HWMODEL,PHONENUM,USERID FROM HARDWARE ORDER BY USER
Hope to have understood your question

Answer 5

SELECT
hw.HWMODEL as HW
,phone.PHONENUM
,user.USERID
FROM
(
SELECT DISTINCT
USERID
FROM
HARDWARE
) as user
LEFT JOIN
(
SELECT
USERID
,PHONENUM
FROM
HARDWARE
WHERE
PHONENUM IS NOT NULL
) as phone
ON phone.USERID = user.USERID
LEFT JOIN
(
SELECT
USERID
,HWMODEL
FROM
HARDWARE
WHERE
HWTYPE = 'PHONE'
) AS hw
ON hw.USERID = user.USERID
ORDER BY
user.USERID
,hw.HWMODEL