For many years, experts associated nostalgia with psychological pain. But over the past decade or so, psychologists have changed their tune. As John Tierney explains in the NYT, research has shown nostalgia can actually be a good thing: It âhas been shown to counteract loneliness, boredom and anxiety.or many years, experts associated nostalgia with psychological pain. But over the past decade or so, psychologists have changed their tune. As John Tierney explains in the NYT, research has shown nostalgia can actually be a good thing: It âhas been shown to counteract loneliness, boredom and anxiety.
What is SQL OUTER JOIN? The SQL OUTER JOIN clause is a variation of the SQL JOIN clause enables a SELECT statement to access more than one table. The JOIN clause controls how tables are linked. It is a qualifier of the SQL FROM clause. The OUTER JOIN clause differs from the standard JOIN clause (also known as the INNER JOIN clause) in that rows are returned even when there are no matches through the JOIN critieria on the second table.
Inner join - Given two tables an inner join returns all rows that exist in both tables left / right (outer) join - Given two tables returns all rows that exist in either the left or right table of your join, plus the rows from the other side will be returned when the join clause is a match or null will be returned for those columns