Reputation: 75965
have a couple of dates in a few fields, basically
SELECT MAX(MAX(DATE_A),MAX(DATE_B)) from table
DATE_A and DATE_B are dates, i basically want the maximum of the latest date of either date A or date B
I searched online but max as a keyword makes it very hard to find what im looking for
Upvotes: 1
Views: 1661
Reputation: 56935
SELECT MAX(GREATEST(date_a,date_b)) FROM table
This first uses GREATEST(date_a,date_b)
to reduce these two columns into just one, containing the greatest value for each row.
The MAX
then selects the one maximum value over all of these.
It also prevents repeated evaluation of MAX
to make things a littler more efficient.
GREATEST
documentation, MAX
documentation.
Note that GREATEST
operates across columns, whereas MAX
operates across rows, which is why you need to use them both to get the single maximum value across both rows and columns.
Upvotes: 3
Reputation: 7887
try this
SELECT IF(MAX(DATE_A)>MAX(DATE_B),MAX(DATE_A), MAX(DATE_B)) FROM table
Upvotes: 0