2

I want to count the number of occurrences of different sensor rows in SQL, but I seem to be doing it wrong and seemingly I am not visualizing it correctly.

If I was doing this in pseudocode in a C style language, I would do it like this:

FOR i in range(taglist[i]):
    
    print(taglist[i], count(taglist[i]) )

I have been trying this:

SELECT COUNT(*)
FROM   (
           SELECT DISTINCT [TagName]
           FROM   [A2ALMDB].[dbo].[AlarmMaster]
           WHERE  (TagName LIKE '%Sensor%' OR GroupName LIKE'%Sensors%')
       ) a

It returns 66, but I want it to return the count of each of the distinct tagnames that are returned in SELECT ... FROM (...)a.

Can anyone help me with how I should be trying to get all the counts of my different sensor occurrences to total instead of a count of all the distinct tagnames?

  • Just to clarify for any beginner who might come across this and get confused, this query as posted wouldn't work. If you run it, it will return an error: "Invalid column name 'a'". The COUNT function accepts either a column reference or a *, and the a in this case is a table reference, not a column. In the actual query probably either something else was there in place of Count(a) or the derived table's column was aliased as a too. – Andriy M Aug 11 at 8:34
4

Sounds like a simple group by:

select tagname, count(*)
from alarmmaster
where tagname like '%Sensor%'  
   or groupname like '%Sensor%'
group by tagname;
| improve this answer | |
  • thank you yes it does seem like i should have been trying to use group by that is doing what i was hoping. Hope this post is helpful for other sql beginners. thanks for the help – LLCoolSteve Aug 17 at 19:23

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