Re: select with combinational conditions

[eohara_kdb]

Assuming your initial table can grow to a large size, probably best to only query it once to get the dates and symbols you’re interested in:

 

q)l:((2023.05.20;`a`b);(2023.05.19;enlist `b);(2023.05.18;`c`d`a);(2023.05.17;`d`a)); 
q)tab:flip `date`data!(2023.05.20 2023.05.20 2023.05.20 2023.05.19 2023.05.19 2023.05.19;`a`c`b`b`b`c); 
q)subset:select from tab where date in l[;0],data in raze l[;1]; 
q)raze{select from y where date=x[0],data in x[1]}[;subset]each l 
date      data 
--------------- 
2023.05.20 a 
2023.05.20 b 
2023.05.19 b 
2023.05.19 b

 

There’s probably a more efficient way but this should do it