I want to run the following query:
CREATE TABLE dummy AS
SELECT x, y, z
FROM table1
WHERE y!=0
then I want to do the following:
if z column has a non-null entry do:
1. copy the content of z into A
2. drop z
SELECT x,A
FROM Dummy
What the second query essentially tries to do is that copy those rows of z into A which have no missing values.
My question is how can we write query 2 and if there is a way to merge these two queries into one for optimisation?
Any help/advice much appreciated.
Best Answer
Since you aren't using column y, you can ignore it in your first query. Then, you can simplify this with a single statement: