locf()

Since 1.1.1

Fill in missing values by carrying the last observed value forward. Use in the same query as time_bucket_gapfill. locf cannot be nested inside another function call.

Arguments

The syntax is:

SELECT locf(
    value = <anyelement>,
    prev = <anyelement>,
    treat_null_as_missing = true | false
);

Name	Type	Default	Required	Description
value	ANY ELEMENT	-	✔	The value to carry forward
prev	EXPRESSION	-	-	If no previous value is available for gapfilling, use the prev lookup expression to get a previous value. For example, you can use prev to fill in the first bucket in a queried time range. The expression must return just a value (not a tuple as expected by the interpolate function) with the same type as the value parameter.
treat_null_as_missing	BOOLEAN	-	-	When true, NULL values are ignored, and only non-NULL values are carried forward.

Returns

Column	Type	Description
locf	ANY ELEMENT	The gapfilled value. The return type matches the input value type.