sql - Selecting column names that have specified value

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