With the following:

q)t:([] e:1 2 3 4 5 6; a:0 0 1 2 3 4; b: 1 2 0 0 3 4; c:1 2 3 4 0 1)

q)t
e a b c
-------
1 0 1 1
2 0 2 2
3 1 0 3
4 2 0 4
5 3 3 0
6 4 4 1

q)colist: `a`b`c

q)colist
`a`b`c

Functional select using value:

q)?[`t; enlist(any;(enlist,value (each;{(=;x;0)};colist))); 0b; ()]
e a b c
-------
1 0 1 1
2 0 2 2
3 1 0 3
4 2 0 4
5 3 3 0

value select fails with symbolic version of colist:

q)?[`t; enlist(any;(enlist,value (each;{(=;x;0)};`colist))); 0b; ()]
'type
  [0]  ?[`t; enlist(any;(enlist,value (each;{(=;x;0)};`colist))); 0b; ()]
       ^

eval version of query works with symbolic version of colist:

q)?[`t; enlist(any;(enlist,eval (each;{(=;x;0)};`colist))); 0b; ()]
e a b c
-------
1 0 1 1
2 0 2 2
3 1 0 3
4 2 0 4
5 3 3 0

But the non-symbolic version of colist fails with eval:

q)?[`t; enlist(any;(enlist,eval (each;{(=;x;0)};colist))); 0b; ()]
'c
  [0]  ?[`t; enlist(any;(enlist,eval (each;{(=;x;0)};colist))); 0b; ()]
                                ^

The k version of each, k){x'y}, works in quotes with value:

q)?[`t; enlist(any;(enlist,value ("k){x'y}";{(=;x;0)};colist))); 0b; ()]
e a b c
-------
1 0 1 1
2 0 2 2
3 1 0 3
4 2 0 4
5 3 3 0

But not with the eval version:

q)?[`t; enlist(any;(enlist,eval ("k){x'y}";{(=;x;0)};`colist))); 0b; ()]
'type
  [0]  ?[`t; enlist(any;(enlist,eval ("k){x'y}";{(=;x;0)};`colist))); 0b; ()]
                                ^

Functional query generall doesn’t work without the value or eval:

q)?[`t; enlist(any;(enlist,(each; {(=;x;0)};`colist))); 0b; ()]
'type
  [0]  ?[`t; enlist(any;(enlist,(each; {(=;x;0)};`colist))); 0b; ()]
       ^

q)?[`t; enlist(any;(enlist,(each; {(=;x;0)};colist))); 0b; ()]
'type
  [0]  ?[`t; enlist(any;(enlist,(each; {(=;x;0)};colist))); 0b; ()]
       ^

q)?[`t; enlist(any;(enlist,("k){x'y}"; {(=;x;0)};`colist))); 0b; ()]
'type
  [0]  ?[`t; enlist(any;(enlist,("k){x'y}"; {(=;x;0)};`colist))); 0b; ()]
       ^

q)?[`t; enlist(any;(enlist,("k){x'y}"; {(=;x;0)};colist))); 0b; ()]
'type
  [0]  ?[`t; enlist(any;(enlist,("k){x'y}"; {(=;x;0)};colist))); 0b; ()]
       ^

1. Why does the value version of the functional select require the non-symbolic version of colist, whereas the eval version does?
2. How does one include the k version of each k){x'y} in the eval version of the functional select?
3. Is there a way to get the functional query to work whic doesn’t require value or eval ?