Question

If I have this table TableABC and it has some fields/columns, rather say it has many fields/columns col1, col2, col3..... say upto 10 or 20, the count doesn’t matter right now.
The point is, I wanna know, if we ask a user for input, say @input varchar(max) or something like this, what I wanna know is that..

How can I select a row, if this input occurs in any column in that row, I mean the row would be selected if col1=@input also if col2=@input and so on..

Now as I said the count of column doesn’t matter, what matters is we don’t know ahead of time the columns so that we may do something like

where
col1 = @input
or
col2 = @input

we can’t do that. I got as far as getting the names of column from table by say

SELECT [name] FROM sys.Columns WHERE [Object_id]=Object_id(N'TableABC')

This would give us names of col in the required table, now I don’t know what can we do with them, or is this even useful in the scenario I am describing? So, what’s the solution?

Lastly, in case someone might ask, where am I gonna use it, or what’s my requirement or something, let me clear its not for (at least as of now!) practical implementation, I just wanna know if its possible, and if so, how? I hope I made myself clear.

Answer 1

You can use cursor to iterate through column names as you suggested and then build dynamic query, later exec it, something like this:

DECLARE @Expression varchar(max)
DECLARE @ColumnName varchar(max)
SELECT @Expression = 'WHERE '

DECLARE db_cursor CURSOR FOR SELECT [name] FROM sys.Columns WHERE [Object_id]=Object_id(N'TableABC')
OPEN db_cursor   
FETCH NEXT FROM db_cursor INTO @ColumnName   

WHILE @@FETCH_STATUS = 0   
BEGIN
    SELECT @Expression = @Expression + @ColumnName + ' = ' + @input + ' AND '

    FETCH NEXT FROM db_cursor INTO @ColumnName   
END 

CLOSE db_cursor   
DEALLOCATE db_cursor

SELECT @Expression
-- EXEC(@Expression) etc...