Question

How can you query a column for any value in that column? (ie. How do I build a dynamic where clause that can either filter the value, or not.)

I want to be able to query for either a specific value, or not. For instance, I might want the value to be 1, but I might want it to be any number.

Is there a way to use a wild card (like “*”), to match any value, so that it can be dynamically inserted where I want no filter?

For instance:

select int_col from table where int_col = 1  // Query for a specific value
select int_col from table where int_col = *  // Query for any value

The reason why I do not want to use 2 separate SQL statements is because I am using this as a SQL Data Source, which can only have 1 select statement.

Answer 1

Sometimes I would query for actual value (like 1, 2…) so I can’t not have a condition either.

I take it you want some dynamic behavior on your WHERE clause, without having to dynamically build your WHERE clause.

With a single parameter, you can use ISNULL (or COALESCE) like this:

 SELECT * FROM Table WHERE ID = ISNULL(@id, ID)

which allows a NULL parameter to match all. Some prefer the longer but more explicit:

 SELECT * FROM Table WHERE (@id IS NULL) OR (ID = @id)