Home/ Questions/Q 7709409
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-01T00:51:17+00:00

I`m new to sql and have been stuck on the following issue for almost

  • 0

I`m new to sql and have been stuck on the following issue for almost a day now:

I have two tables that I pull values from, devices and devices_LOG. I need to display all the devices_LOG entries where devices.status = ‘1’ AND I need them to be unique (ie I only want to see one devices_LOG entry for each device). My code looks like this:

    SELECT DISTINCT 
                     devices_LOG.device_id, MAX(devices_LOG.LogDate) AS LogDate,
                     manufacturers.name, devices_LOG.LogType, devices_LOG.userName, 
                     devices_LOG.userFullname, devices.invnumber, devices.modelname,
                     devices.modelnumber
    FROM             devices_LOG 
    INNER JOIN
                     devices ON devices_LOG.device_id = devices.id AND 
                     devices_LOG.device_id = devices.id 
    INNER JOIN
                     manufacturers ON devices.manufacturer_id = manufacturers.id
    WHERE            (devices.devicestatus = '1') AND (devices_LOG.LogType = 'Out')
    GROUP BY         devices_LOG.device_id, manufacturers.name, devices_LOG.LogType,
                     devices_LOG.userName, devices_LOG.userFullname, devices.invnumber, 
                     devices.modelname, devices.modelnumber
    ORDER BY         devices_LOG.device_id

which is great for returning only entries for things that have device.status = ‘1’, but it returns multiple log entries for something with the same device.id. So, the results of my query look like this

    device_id  LogDate       username    LogType    modelname   ...etc
    1          11/12/2011    foo         out        generic
    1          11/10/2011    world       out        generic
    2          9/10/2011     hello       out        generic3
    2          8/9/2011      bye         out        generic3

when I need it to look like this:

    device_id  LogDate       username    LogType    modelname   ...etc
    1          11/12/2011    foo         out        generic
    2          9/10/2011     hello       out        generic3

I tried using MAX on LogDate, tried grouping, select distinct, etc….but I just can`t figure it out. Any ideas?

I realize my sql statement is pretty ugly right now, probably because I have been trying everything I can think of up to this point with no luck, so any help would be greatly appreciated, thanks

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Just wrap the log entry in a CTE and use ROW_NUMBER with partition to get the data you want.

    For example if you wanted the oldest log entry, you could change the ORDER BY LogDate DESC into ASC.

    WITH Log AS (
SELECT ROW_NUMBER() OVER (PARTITION BY device_id ORDER BY LogDate DESC) AS RN, *
FROM Devices_LOG
WHERE LogType = 'Out'
)

SELECT DISTINCT 
                     Log.device_id, Log.LogDate AS LogDate,
                     manufacturers.name, Log.LogType, Log.userName, 
                     Log.userFullname, devices.invnumber, devices.modelname,
                     devices.modelnumber
    FROM             devices 
    INNER JOIN
                     Log ON Log.device_id = devices.id AND 
                     Log.RN = 1 
    INNER JOIN
                     manufacturers ON devices.manufacturer_id = manufacturers.id
    WHERE            (devices.devicestatus = '1')
    ORDER BY         devices.device_id
    • 0