Reply To: simplifying code using multiple fby possible?

[rocuinneagain]

t:([] payment_type:10#CARDCASH;vendor:10#abcd`e;fare:10?50;tip:10?50)
t
payment_type vendor fare tip
----------------------------
CARD         a      30   39
CASH         b      17   0
CARD         c      23   49
CASH         d      44   46
CARD         e      12   41
CASH         a      2    18
CARD         b      36   49
CASH         c      37   40
CARD         d      44   24
CASH         e      28   13
select from t where ({exec (tip=max tip) and (fare>avg fare) from x};([] tip;fare)) fby vendor
payment_type vendor fare tip
----------------------------
CARD         a      30   39
CARD         b      36   49

You can pass in sub tables to aggregate on more than one column

fby – Reference – kdb+ and q documentation – kdb+ and q documentation (kx.com)