Added negative lookahead
Added negative lookahead

It is possible to have multiple occurrences of 'as' in a field name.
Use the last occurrence of 'as' when extracting field name.

Tested with following examples:
"WeldCheck"."weld_id"
count(*) as WeldCheck__num_measurements
count(case decision when 2 then 1 else null end) as
WeldCheck__num_failures
avg(cast (WeldMeasurement.surface_indentation as bigint)) as
WeldCheck__avg_indentation
avg(cast (WeldMeasurement.circle_diameter as bigint)) as
WeldCheck__avg_diameter

et304383/passbolt_api,et304383/passbolt_api,et304383/passbolt_api,et304383/passbolt_api,et304383/passbolt_api