Find max of 3 values

Question

Hello,
I am currently performing an update using a CASE statement, however my last condition is when I'm stuck:
UPDATE X
SET DATE =
CASE WHEN RATE = 'a' THEN
DATE_IN + ((col1 / col2) * 7)
ELSE
CASE WHEN RATE = 'b' THEN
DATE_IN + ((col1 / col2) * 7)
ELSE
CASE WHEN RATE = 'c' THEN
DATE_IN + ((col1 / col2) * 7)
else
case when rate = 'd' then
****HERE IS THE ISSUE****
END END END ;
When the rate is 'd', I need to use the max of the other 3 rates.
Any comments would be appreciated.

Answer 1

shane_1004 wrote:
Hello,
I am currently performing an update using a CASE statement, however my last condition is when I'm stuck:
UPDATE X
SET DATE =
CASE WHEN RATE = 'a' THEN
DATE_IN + ((col1 / col2) * 7)
ELSE
CASE WHEN RATE = 'b' THEN
DATE_IN + ((col1 / col2) * 7)
ELSE
CASE WHEN RATE = 'c' THEN
DATE_IN + ((col1 / col2) * 7)
else
case when rate = 'd' then
****HERE IS THE ISSUE****
END END END ;
When the rate is 'd', I need to use the max of the other 3 rates.The "other 3 rates" are all the same:
        DATE_IN + ((col1 / col2) * 7) Assuming they were different, you could use the GREATEST function. Make sure none of the arguments to GREATEST are NULL.
To avoid repeating some computations, you can do them in a sub-query, and refer to the column aliases in the main query. When doing an UPDATE, this will probably be slower; only you can tell if the programming convenience is worth the extra execution time.
As Alex said, post some sample data and the results you want from that data (that is, the contents of the table after the UPDATE) if you want help.