topic How tAggregateRow works? in Talend Studio

How tAggregateRow works?

_AnonymousUser — Sat, 16 Nov 2024 13:25:54 GMT

Hi,
I hope you can help me.
I'm reading Component Guide of Talend and I just can't understand
how the tAggregateRow works ( Page 710 ).
Some questions:
1. How can I know what the functions do? (count, min,
max, avg, sum, first, last, list, list(objects),
count(distinct), standard deviation).
2. In the manual, in 'Input Column Position', he puts 'Points' without show what it means.
3. Finally, in the manual, he didn't show the types that should been chosen (String,int,float,...)
Thnks a lot, and I'm so sorry because my english is not good, I'm Brazilian.

Re: How tAggregateRow works?

Anonymous — Fri, 14 May 2010 02:46:14 GMT

Hello

1. How can I know what the functions do? (count, min,
max, avg, sum, first, last, list, list(objects),
count(distinct), standard deviation).

There are common aggregate logic function, for example, count get the number of rows group by the key columns. min get the minimum value of rows group by the key columns.

2. In the manual, in 'Input Column Position', he puts 'Points' without show what it means.

In the 'input column position' choose the columns from input schema as group keys.

3. Finally, in the manual, he didn't show the types that should been chosen (String,int,float,...)

The data type is defined on the schema.
Best regards
Shong

Re: How tAggregateRow works?

_AnonymousUser — Fri, 14 May 2010 15:14:31 GMT

shong,
Thank for your answer, but I still can't understand some points.
Like I said, in the manual is not specified the type that I have to choose in the schema,
so I'm choosing and receiving this message:
"Warning: the operation 'count ' for the output column 'Name1' can't be processed
because of incompatible input and/or output types. "
I want to compare two columns of names, and to do that, I'm choosing that two like 'key'.
In the types I'm putting 'String' and I'm adding 3 columns: 'Average', 'Max' and 'Min', all
of them like double.
Thank you.

Re: How tAggregateRow works?

Anonymous — Fri, 14 May 2010 16:14:20 GMT

in your output schema you have a column named "Name1". In the operation menu of the tAggregateRow you shoudl have a line with a count operation (with Name1 defined as an output column, right ?).
So now if you take a look on your output schema Name1's type should be String which is wrong, since a count operation return a numeric value (change it to Integer). Same logic for others output columns that will contains results of Sum, Average...