Dense Rank function in talend

[Anonymous]

BI want to know how to use dense rank in this condition.if highest Marks having 3rows and lowest marks also 3 rows then how to find out that one.

[Anonymous · Accepted solution]

I may have missed a setting in a component (if I have, I'd be interested to know about this) but I do not believe this functionality has been implemented. But it is very easy to implement if you use a tSortRow and a tMap. The tSortRow is self explanatory, but the tMap is a little more complicated to understand. In a tMap you can create tMap variables whic are processed from the top to the bottom in a strict order, they also keep their values between rows. Using this, we can keep track of when values change and implement a simple addition to a ranking number when the values change from the last row. This allows us to implement a dense rank. I have knocked up a brief example in Talend 6.2.1.

DenseRankExample.zip