Does the order of columns in a WHERE clause matter?

Question

Does the order of the columns in a WHERE clause effect performance?

e.g.

Say I put a column that has a higher potential for uniqueness first or visa versa?

Answer 1

With a decent query optimiser: it shouldn't.

But in practice, I suspect it might.

You can only tell for your cases by measuring. And the measurements will likely change as the distribution of data changes in the database.