dynamic column names

Community Support
1

In SQL, you can rename columns in a query dynamically using [as “my column”]. I want to be able to pass in a column name to a function which does a select and have the resulting table use the names passed in. How can this be accomplished in q?

Thanks,
–Ray

2

Select newname: oldname from table

Work for you?

3

Hi,
You can achieve all this using functional select.

http://code.kx.com/wiki/JB:QforMortals2/queries_q_sql#Functional_select

Thanks Rory

4

there is also xcol, which allows column renaming:

f:{[cs] cs xcol select … from t }?

5

Thanks very much, xcol will work fine, I should have seen that myself.

6

q)getcol:{ c:“,” sv string (),x; value 0N!“select “,c,” from tab”}
q)getcol col1col2

7

watch out with that one - it will work only for tab as a global.

q)getcol:{ c:“,” sv string (),x; value 0N!“select “,c,” from t”}

q){t:(a:til 5);getcol `a}

“select a from t”

{c:“,” sv string (),x; value 0N!“select “,c,” from t”}

't

.:

“select a from t”

q))

functional select is preferred for this kind of task.