How to count rows when there are no rows

PhilHibbs — Wed, 03 Oct 2018 15:47:28 GMT

I want to count the number of rows, but in the case that there are no rows, I want to get a result saying zero, not nothing at all.

I tried tFixedFlowInput -> tUnite -> tAggregateRow, and selecting "Ignore null values", but my row structure just contains a string (that I am grouping by) and an int, and you can't set an int to null.

I could add a dummy column, but that's a bit messy, I don't want to add any more components than I need.

I could just subtract 1 from the count, but that's an extra tJavaRow or tMap, and will lead to confusion.

If I want to do something more complex as well, like calculate a standard deviation, then the dummy row with a zero integer value will throw the statistics out.

I could tUnite a dummy row after the tAggregateRow and aggregate that in, but that's extra processing and an extra component and confusion.

Is there a "good" way to do this? There are plenty of messy ways.

Re: How to count rows when there are no rows

Anonymous — Wed, 03 Oct 2018 16:51:01 GMT

Many components have built in global variables. One of them that is common to a lot if them is row count or # of lines processed. You would typically retrieve this after that subjob is completed.

For example, tFixedFlowInput's is

((Integer)globalMap.get("tFixedFlowInput_2_NB_LINE"))

for something like tMSSqlInput you would use

((Integer)globalMap.get("tMSSqlInput_1_NB_LINE"))

This will also report if there are 0 rows.

topic Re: How to count rows when there are no rows in Talend Studio

How to count rows when there are no rows

Re: How to count rows when there are no rows