outputRow()

After each call to the processRow() method, if the outputRow() method is defined, it is called until it returns null. This allows a UDTF to output any number of rows efficiently. The outputRow() method is always called with one parameter, which is the number of times outputRow() has been called since the processRow() method was called.

Here is an example of using outputRow() in combination with processRow(). The processRow() method is called first and stores the value of x in the rows_to_output variable. The Netezza database then calls the outputRow() method until it returns null. On the first call, the rownum argument has the value 1, the second call it has the value 2, etc.

function processRow(x)
rows_to_output = x
return null

end

function outputRow(rownum)
if rownum > rows_to_output then
return null
end
return { rownum }
end

Once the outputRow() method has returned null, the Netezza database then calls the processRow() method again with the next row of data to be processed. The outputRow() method must return data in exactly the same format as is allowed for the processRow() method.

Even if the processRow() method returns a result, the outputRow() method is still called after each call to processRow(). For example:

function processRow(x)
rows_to_output = x
return { 0 }

end

function outputRow(rownum)
if rownum > rows_to_output then
return null
end
return { rownum }
end