nullsfirst

Description

Specify the ordering as nulls first when processing data. This is used by ordered windowing functions (like lag and last), ordered aggregation functions (like array_agg) and the sort verb.

Return type

ordering

Domain

This is a scalar function (calculates a single output value for a single input row.)

Categories

Usage

nullsfirst( columnname )

Argument

Type

Required

Multiple

Constant

columnname

ordering

Required

Only one

Variable

Examples

sort nullsfirst(foo)

Sort the dataset with nulls first in column foo.

statsby list:array_agg(username, asc(nullsfirst(timestamp))), group_by(hostname)

Lists all users for each host, in order of ascending timestamp with nulls first within each host assuming you have a table with columns timestamp, hostname and username.