q/KDB Selecting multiple symbols using functional select

Question

I am trying to select multiple symbols using function select but it is throwing an error :

d:([] s:5#`v`b ; p:5?10)
?[d;enlist (in;`s;(),`v`b);0b;()]
'b

however, when I select a single symbol, it returns correct data

?[d;enlist (in;`s;(),`v);0b;()]
s p
---
v 8
v 4
v 2

what exactly is wrong with my query?

Answer 1

If you run parse on the equivalent q-sql expression you will see , in parse tree:

q)parse"select from d where s in`v`b"
?
`d
,,(in;`s;,`v`b)
0b
()

This means enlist, so if you sub that in instead the query should work:

q)?[d;enlist(in;`s;enlist`v`b);0b;()]
s p
---
v 8
b 1
v 9
b 5
v 4
q)?[d;enlist(in;`s;enlist`v);0b;()]
s p
---
v 8
v 9
v 4