Selecting column names that have specified value - sql

Question

We are receiving rather large files, of which we have no control over the format of, that are being bulk-loaded into a SQL Server table via SSIS to be later imported into our internal structure. These files can contain over 800 columns, and often the column names are not immediately recognizable.
As a result, we have a large table that represents the contents of the file with over 800 Varchar columns.
The problem is: I know what specific values I'm looking for in this data, but I do not know what column contains it. And eyeballing the data to find said column is neither efficient nor ideal.
My question is: is it at all possible to search a table by some value N and return the column names that have that value? I'd post some code that I've tried, but I really don't know where to start on this one... or if it's even possible.
For example:
A B C D E F G H I J K L M N ...
------------------------------------------------------------
'a' 'a' 'a' 'a' 'a' 'b' 'a' 'a' 'a' 'b' 'b' 'a' 'a' 'c' ...
If I were to search this table for the value 'b', I would want to get back the following results:
Columns
---------
F
J
K
Is something like this possible to do?

Answer 1

This script will search all tables and all string columns for a specific string. You might be able to adapt this for your needs:
DECLARE #tableName sysname
DECLARE #columnName sysname
DECLARE #value varchar(100)
DECLARE #sql varchar(2000)
DECLARE #sqlPreamble varchar(100)
SET #value = 'EDUQ4' -- *** Set this to the value you're searching for *** --
SET #sqlPreamble = 'IF EXISTS (SELECT 1 FROM '
DECLARE theTableCursor CURSOR FAST_FORWARD FOR
SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'dbo' AND TABLE_TYPE = 'BASE TABLE'
AND TABLE_NAME NOT LIKE '%temp%' AND TABLE_NAME != 'dtproperties' AND TABLE_NAME != 'sysdiagrams'
ORDER BY TABLE_NAME
OPEN theTableCursor
FETCH NEXT FROM theTableCursor INTO #tableName
WHILE ##FETCH_STATUS = 0 -- spin through Table entries
BEGIN
DECLARE theColumnCursor CURSOR FAST_FORWARD FOR
SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = #tableName AND (DATA_TYPE = 'nvarchar' OR DATA_TYPE = 'varchar')
ORDER BY ORDINAL_POSITION
OPEN theColumnCursor
FETCH NEXT FROM theColumnCursor INTO #columnName
WHILE ##FETCH_STATUS = 0 -- spin through Column entries
BEGIN
SET #sql = #tableName + ' WHERE ' + #columnName + ' LIKE ''' + #value +
''') PRINT ''Value found in Table: ' + #tableName + ', Column: ' + #columnName + ''''
EXEC (#sqlPreamble + #sql)
FETCH NEXT FROM theColumnCursor INTO #columnName
END
CLOSE theColumnCursor
DEALLOCATE theColumnCursor
FETCH NEXT FROM theTableCursor INTO #tableName
END
CLOSE theTableCursor
DEALLOCATE theTableCursor

Answer 2

One option you have is to be a little creative using XML in SQL Server.
Turn a row at a time into XML using cross apply and query for the nodes that has a certain value in a second cross apply.
Finally you output the distinct list of node names.
declare #Value nvarchar(max)
set #Value= 'b'
select distinct T3.X.value('local-name(.)', 'nvarchar(128)') as ColName
from YourTable as T1
cross apply (select T1.* for xml path(''), type) as T2(X)
cross apply T2.X.nodes('*[text() = sql:variable("#Value")]') as T3(X)
SQL Fiddle

Answer 3

If you have access to the files are RegEx will be must faster than performing a generic search in SQL.
If you are forced to use SQL #pmbAustin's answer is the way to go. Be warned, it won't run quickly.