Why would someone use WHERE 1=1 AND in a SQL clause?

Question

Why would someone use WHERE 1=1 AND in a SQL clause (Either SQL obtained through concatenated strings, either view definition)

I\'ve

Answer 1

Here's a closely related example: using a SQL MERGE statement to update the target tabled using all values from the source table where there is no common attribute on which to join on e.g.

MERGE INTO Circles
   USING 
      (
        SELECT pi
         FROM Constants
      ) AS SourceTable
   ON 1 = 1
WHEN MATCHED THEN 
  UPDATE
     SET circumference = 2 * SourceTable.pi * radius;