Get a substring from a column and perform a groupBy and count

Question

I have a table that stores data about a large number of files, such as their language, unique ID, file path etc. I want to be able to get the sub-string from the unique ID which

Answer 1

Sounds like you want a COUNT and a GROUP BY:

SELECT 
  SUBSTRING(AssetID,1,2), 
  COUNT(*) Total
FROM [table]
GROUP BY SUBSTRING(AssetID,1,2)

You did not specify what database but, if you are using SQL Server and LCID is in your SELECT statement, then you will need to include it in your GROUP BY clause.

If the LCID value is unique for each row then you will get multiple records for each AssetID because it will try to group the unique values together. As a result, I removed the LCID.

If it is not unique, then you can use:

SELECT LCID, 
  SUBSTRING(AssetID,1,2), 
  COUNT(*) Total
FROM [table]
GROUP BY LCID, SUBSTRING(AssetID,1,2)

Based on the edits that you made, you want a PIVOT which transforms the data from rows into columns. For a PIVOT you will use:

select LCID, HA, HT, HP, FH, FX
from
(
  SELECT LCID, 
    SUBSTRING(AssetID,1,2) AssetID
  FROM [table]
) src
pivot
(
  count(AssetID)
  for AssetID in (HA, HT, HP, FH, FX) -- place more values here
) piv

If the values are unknown that you want to transform into columns, then you will need to use dynamic SQL similar to this:

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(SUBSTRING(AssetID,1,2)) 
                    from [table]
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT LCID, ' + @cols + ' from 
             (
                SELECT LCID, 
                  SUBSTRING(AssetID,1,2) AssetID
                FROM [table]
            ) x
            pivot 
            (
                count(AssetID)
                for AssetID in (' + @cols + ')
            ) p '

execute(@query)