ch.total()

Read(916) Label: channel, aggregation,

Description:

Perform aggregation over records in a channel.

Syntax:

ch.total(y,…)

Note:

The function performs aggregation over records in a channel. Parameter y is the aggregate function over cs. The function returns a single value when there is only one aggregate function; or returns multiple values in order for multiple aggregate functions. This is an attached computation.

Parameter:

ch

Channel

y

Aggregate function, only support sum/count/max/min/top/avg/iterate; Parameter Gi should not be present when the function works with iterate(x,a;Gi,…) function

Return value:

Numeric value or a sequence of numeric values

Example:

 

A

 

1

=demo.cursor("select * from SCORES where CLASS = 'Class one'")

 

2

=channel()

Create a channel.

3

=channel()

 

4

=A1.push(A2,A3)

Be ready to push A1’s data to channels A2 and A3. 

5

=A2.total(sum(SCORE))

Perform an aggregation over records in channel A2.

6

=A3.total(sum(SCORE),count(SUBJECT),max(SCORE))

Perform multiple aggregations over records in channel A3.

7

=A1.fetch()

Fetch data from cursor A1 when operations in the channel begin to be executed and cursor data is pushed into the channel.

8

=A2.result()

9

=A3.result()