Query Shows multiple listings of same info - sql

Question

I'm using this query to find all the machines on the network (using dell kace) that have an expired warranty according to their service tag.
However, when I run the query, some of the machines are listed twice but should only be listed once.
Here is an example of the output where machine example3 is correctly listed but example1 is listed twice.
# Machine Name Service Tag
1 example1 abcd123
2 example1 abcd123
3 example3 abcd124
Code:
SELECT
M.NAME AS MACHINE_NAME, M.CS_MODEL AS MODEL, DA.SERVICE_TAG,
DA.SHIP_DATE,M.USER_LOGGED AS LAST_LOGGED_IN_USER, DW.SERVICE_LEVEL_CODE,
DW.SERVICE_LEVEL_DESCRIPTION, DW.END_DATE AS EXPIRATION_DATE
FROM
DELL_WARRANTY DW
JOIN
DELL_ASSET DA ON (DW.SERVICE_TAG = DA.SERVICE_TAG)
JOIN
MACHINE M
ON (M.BIOS_SERIAL_NUMBER = DA.PARENT_SERVICE_TAG OR M.BIOS_SERIAL_NUMBER = DA.SERVICE_TAG)
LEFT JOIN
DELL_WARRANTY DW2 ON DW2.SERVICE_TAG=DW.SERVICE_TAG and DW2.END_DATE > NOW()
WHERE
M.CS_MANUFACTURER LIKE '%dell%'
AND
M.BIOS_SERIAL_NUMBER!=''
AND
DA.DISABLED != 1
AND
DW.END_DATE < NOW()
AND
DW2.SERVICE_TAG IS NULL;
Any ideas on how to make computers with the same machine name and service tags only output once? Thanks.

Answer 1

Let me make the assumption that you have a reasonable data model and reasonably populated data. That means that the duplicates are not coming from inappropriate data stored in the database.
Your query (formatted so I can read it) is:
SELECT M.NAME AS MACHINE_NAME, M.CS_MODEL AS MODEL, DA.SERVICE_TAG,
DA.SHIP_DATE, M.USER_LOGGED AS LAST_LOGGED_IN_USER, DW.SERVICE_LEVEL_CODE,
DW.SERVICE_LEVEL_DESCRIPTION, DW.END_DATE AS EXPIRATION_DATE
FROM DELL_WARRANTY DW JOIN
DELL_ASSET DA
ON DW.SERVICE_TAG = DA.SERVICE_TAG JOIN
MACHINE M
ON M.BIOS_SERIAL_NUMBER = DA.PARENT_SERVICE_TAG OR
M.BIOS_SERIAL_NUMBER = DA.SERVICE_TAG LEFT JOIN
DELL_WARRANTY DW2
ON DW2.SERVICE_TAG = DW.SERVICE_TAG and DW2.END_DATE > NOW()
WHERE M.CS_MANUFACTURER LIKE '%dell%' AND
M.BIOS_SERIAL_NUMBER <> '' AND
DA.DISABLED <> 1;
The suspect join is the one on Machine because it has an or. So, two machines might match different parts of the service tag, resulting in multiple very similar rows.
If your concern is specifically about machine names and service tags (the two columns you highlighted in the question), then you can fix those duplicates by ending the query with:
group by M.NAME, DA.SERVICE_TAG
(This assumes that you are using MySQL -- based on the syntax of your query. Most other databases would require aggregation functions around the rest of the columns in select.)

Answer 2

Try putting a DISTINCT infront of M.Name
OR playing with the joins like
SELECT
M.NAME AS MACHINE_NAME, M.CS_MODEL AS MODEL, DA.SERVICE_TAG,
DA.SHIP_DATE,M.USER_LOGGED AS LAST_LOGGED_IN_USER, DW.SERVICE_LEVEL_CODE,
DW.SERVICE_LEVEL_DESCRIPTION, DW.END_DATE AS EXPIRATION_DATE
FROM
DELL_WARRANTY DW
INNER JOIN
DELL_ASSET DA ON (DW.SERVICE_TAG = DA.SERVICE_TAG)
INNER JOIN
MACHINE M
ON (M.BIOS_SERIAL_NUMBER = DA.PARENT_SERVICE_TAG OR M.BIOS_SERIAL_NUMBER = DA.SERVICE_TAG)
INNER JOIN
DELL_WARRANTY DW2 ON DW2.SERVICE_TAG=DW.SERVICE_TAG and DW2.END_DATE > NOW()
WHERE
M.CS_MANUFACTURER LIKE '%dell%'
AND
M.BIOS_SERIAL_NUMBER!=''
AND
DA.DISABLED != 1
AND
DW.END_DATE < NOW()
AND
DW2.SERVICE_TAG IS NULL;