getShape()

Unlike a UDF or UDA, a UDTF can return multiple columns. Here is a simple example:

function getShape()
local shape = {}
shape[1] = { "x", integer }
shape[2] = { "y", integer }
shape[3] = { "z", varchar(255) }
return shape

end

In this example, the UDTF is defined to return three columns of data. Based on the getShape() method show above, the processRow() method returns three columns of data that match the format defined by the getShape() method. For example, the processRow() method definition could could look like this:

function processRow(a,b,c)
return { a*10, b-10, "foobar" }

end

A special case for the getShape() method is to allow the UDTF to determine the output shape at runtime. When the getShape method returns the value VARSHAPE the calculateShape() method is called at runtime to determine the output columns based on the constant arguments that are used to invoke the UDTF.

function getShape()
return VARSHAPE

end