Swapping column values in Oracle

Question

I was solving one of the puzzles and came across swapping column values using DML queries:

SELECT * FROM TEMP_TABLE;
ID1, ID2
--------
20, 15
20, 15
20, 15
         


        

Answer 1

There's no need to have three update statements, one is sufficient:

UPDATE temp_table_new 
SET    id1 = id2, 
       id2 = id1;