locf()

Fill in missing values by carrying the last observed value forward

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.