As-of join

t1 asof t2     asof[t1;t2]

Where

• t1 is a table
• t2 is a table or dictionary
• the last key or column of t2 corresponds to a time column in t1

returns the values from the last rows matching the rest of the keys and time ≤ the time in t2.

q)show trade asof`sym`time!(`IBM;09:30:00.0)
price| 96.3e
size | 200
stop | 0b
corr | 0
cond | "T"
ex   | "D"

q)show trade asof([]sym:`AAPL`IBM;ex:"TD";time:09:30:00.0)
price size stop corr cond
-------------------------
78.14 100  0    0    T
96.3  200  0    0    T