What is the SQL for 'next' and 'previous' in a table?

Question

I have a table of items, each of which has a date associated with it. If I have the date associated with one item, how do I query the database with SQL to get the \'previous

Answer 1

If your RDBMS supports LAG and LEAD, this is straightforward (Oracle, PostgreSQL, SQL Server 2012)

These allow to choose the row either side of any given row in a single query