Question

Table name : – Trade

TradeNumber       spread
1                 .1
1                 .1
2                 .3
2                 .4

I want to get all the trades where spread varies. That is my result set should contain only trade number 2.

The query I could construct is

select TradeNumber from Trade t where t.spread <> (select t.spread from TradeNumber)

Didn’t get a chance to run it. Is there an aggregating/ compound function to solve it ?

Answer 1

The least expensive way to do this is:

select tradenumber
from t
group by tradenumber
having min(spread) <> max(spread)

Using min and max users fewer resources than count(distinct).