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Max versus Greatest in Oracle

So I was trying to figure out the greatest of three dates in oracle. They were coming from 3 different columns across three different tables. So I figured I could do something like the following

SELECT MAX(A.date, B.date, C.date) FROM. . .etc

But apparently that doesn't work. The max function will not work across multiple columns. That's when I learned about the greatest function. Does the same thing as max, but lets you do it across multiple columns. The above query became

SELECT GREATEST(A.date, B.date, C.date) FROM . . .etc.

So, Max = one column, Greatest = multiple columns.

Labels: Oracle

posted by Tom Becker at 12/03/2008