The first parameter of
REMAP_VALUES is an input column of type STRING that provides the values that should be remapped. The second parameter is a list of one or more pairs of string values
that describe the mapping. Each occurrence of the first value of the pair will be remapped to the second value of the pair.
If a value is remapped in multiple pairs, only the last pair is used. Finally, the operator accepts an optional string
value that will replace all values that are not remapped within the mapping.
If this optional default replacement value is missing, all values not considered in the mapping will remain unchanged.
REMAP_VALUES operator is only applicable to columns of type string,
provides a similar functionality for columns of type INT.
You can achieve the same result with a CASE WHEN statement
REMAP_INTS is faster and the syntax is more compact.
If the input value is NULL and it is not mapped to any other value, REMAP_VALUES / REMAP_INTS will return NULL again.