kdb+；：分组方式和多列求和

考虑以下数据：

table:

time          colA    colB     colC
-----------------------------------
11:30:04.194  31      250      a
11:30:04.441  31      280      a
11:30:14.761  31.6    100      a
11:30:21.324  34      100      a
11:30:38.991  32      100      b
11:31:20.968  32      100      b
11:31:56.922  32.2    1000     b
11:31:57.035  32.6    5000     c
11:32:05.810  33      100      c
11:32:05.810  33      100      a
11:32:14.461  32      300      b

现在，当

colC

相同时，我如何才能

sum

colB

而不丢失时间顺序

因此，输出将是：

first time    avgA    sumB     colC
-----------------------------------
11:30:04.194  31.2    730      a
11:30:38.991  32.07   1200     b
11:31:57.035  32.8    5100     c
11:32:05.810  33      100      a
11:32:14.461  32      300      b

到目前为止，我所拥有的：

select by time from (select first time, avg colA, sum colB by colC, time from table)

但是输出不是按

colC

分组的。查询应该是什么样子？

这个怎么样

get select first time, avg colA, sum colB, first colC by sums colC<>prev colC from table

get select first time，avg colA，sum colB，first colC by sums colCprev colC from table

这个怎么样

get select first time, avg colA, sum colB, first colC by sums colC<>prev colC from table

get select first time，avg colA，sum colB，first colC by sums colCprev colC from table

使用

different

实现这一点的方法稍有不同：

value select  first time, avg colA, sum colB , first colC by g:(sums differ colC) from table 

---

使用

different

实现此目的的方法稍有不同：

value select  first time, avg colA, sum colB , first colC by g:(sums differ colC) from table