Counting occurrences in a table - sql

Question

Lets say I want to count the total number of occurrences of a name contained within a string in a column and display that total next to all occurrences of that name in a new column beside it. For example, if I have:
Name | Home Address | Special ID
==================================
Frank | 152414 | aTRF342
Jane | 4342342 | rRFC432
Mary | 423432 | xTRF353
James | 32111111 | tLZQ399
May | 4302443 | 3TRF322
How would I count the occurrences of special tags like 'TRF', 'RFC', or 'LZQ' so the table looks like this:
Name | Home Address | Special ID | Occurrences
================================================
Frank | 152414 | aTRF342 | 3
Jane | 4342342 | rRFC432 | 1
Mary | 423432 | xTRF353 | 3
James | 32111111 | tLZQ399 | 1
May | 4302443 | 3TRF322 | 3
Currently using Access 2007. Is this even possible using a SQL query?

Answer 1

Using Access 2007, I stored your sample data in a table named tblUser1384831. The query below returns this result set.
Name Home Address Special ID special_tag Occurrences
---- ------------ ---------- ----------- -----------
Frank 152414 aTRF342 TRF 3
Jane 4342342 rRFC432 RFC 1
Mary 423432 xTRF353 TRF 3
James 32111111 tLZQ399 LZQ 1
May 4302443 3TRF322 TRF 3
Although your question has a vba tag, you don't need to use a VBA procedure for this. You can do it with SQL and the Mid() function.
SELECT
base.[Name],
base.[Home Address],
base.[Special ID],
base.special_tag,
tag_count.Occurrences
FROM
(
SELECT
[Name],
[Home Address],
[Special ID],
Mid([Special ID],2,3) AS special_tag
FROM tblUser1384831
) AS base
INNER JOIN
(
SELECT
Mid([Special ID],2,3) AS special_tag,
Count(*) AS Occurrences
FROM tblUser1384831
GROUP BY Mid([Special ID],2,3)
) AS tag_count
ON base.special_tag = tag_count.special_tag;

Answer 2

You would have to GROUP BY the substring of Special ID. In MS Access, you can read about how to compute substrings here.
The problem in your case is that your data in Special ID column does not follow a standard pattern, one which easy to extract via the substring function. You might need to use regular expressions to extract such values, and later apply the GROUP BY to them.
With MSSQL, Oracle, PostgreSQL you would be able to declare a stored procedure (example CLR function in MS SQL Server) that would do this for you. Not sure with MS Access.

Answer 3

you can do something like this:
select Name, [Home Address], [Special ID],
(select count(*) from [your table] where [Special ID] = RemoveNonAlphaCharacters([Special ID]) ) as Occurrences
from [your table]
auxiliar function (got from this link):
Create Function [dbo].[RemoveNonAlphaCharacters](#Temp VarChar(1000))
Returns VarChar(1000)
AS
Begin
While PatIndex('%[^a-z]%', #Temp) > 0
Set #Temp = Stuff(#Temp, PatIndex('%[^a-z]%', #Temp), 1, '')
Return #Temp
End

Answer 4

lets say your first table is called 'table_with_string'
the following code will show the occurance based on the first 3 charecters of string in Special ID column. since it is not clear how exactly you are passing the string to match
select tws.Name,tws.HomeAddress,tws.SpecialID,str_count.Occurrences from
table_with_string tws
left join
(select SpecialID,count(*) from table_with_string where specialID like(substring
(specialid,0,3))
group by specialId) as str_count(id,Occurrences)
on str_count.id=tws.SpecialID

Answer 5

I would suggest doing this explicitly as a join, so you are clear on how it works:
select tws.Name, tws.HomeAddress, tws.SpecialID, str_count.Occurrences
from table_with_string tws
join
(
select substring(spcecialid, 2, 3) as code, count(*) as Occurrences
from table_with_string tws
group by substring(spcecialid, 2, 3)
) s
on s.code = substring(tws.spcecialid, 2, 3)