kdb+ and q

Resolved! update column name in partitioned table

I have a partitioned table t with columns date, class, nan. I want to update the column "nan" to "name".I am trying this: `date`class`name xcol t This is not working. Please help me out here guys:)

Resolved! Running user defined aggregation on partitioned tables

Hello I want to run a user defined aggregating function getPercentile (to get say 99% or 50% or 1% percentile of a list of value) on a partitioned table. From this link map-reduce , only few types of aggregation can KDB decompose into map step and re...

Resolved! Why Q SQL doesn't work with "in"?

I have codes as below. Why the last line would fail? How to make it work? Thanks! t:([] c1:`a`b`a`c`b`c; c2:1 1 1 2 2 2; c3:10 20 30 40 50 60);select from t where c1 in enlist `a; // worksselect from t where c1 in `a`b; // works?[t;enlist (in;`c1;enl...

Resolved! In funtional qSQL, what is the meaning when the operator is a list?

In the below code, I can understand the meaning of (<), but cannot understand the meaning of (';~:;<). Why line 3 keeps 4 rows, while line 4 keeps 6 rows? What is the meaning of "~:" here? t:([] c1:`a`b`c`d`e`f; c2:1 1 1 2 2 2; c3:10 20 30 40 50 60);...