I am trying to make a SQL query (to be converted into a SSRS report) that will grab everything opened in the previous day. This will have to be ran every day, automatically, so entering in the date manually will not be an option really.
Safest (in terms of changes to, or implicit conversion of, underlying data types) and most efficient (in terms of best chance at using an index to seek) is an open-ended range:
WHERE datetime_column >= DATEADD(DAY, DATEDIFF(DAY, 1, GETDATE()),0)
AND datetime_column < DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()),0);
For some details, see: