Я думаю, что в BigQuery Standard SQL это будет
#standardSQL
SELECT REGEXP_REPLACE(V2location, r',.*', '') theme, COUNT(1) AS count
FROM `gdelt-bq.gdeltv2.gkg`, UNNEST(SPLIT(V2locations,';')) V2location
WHERE DATE > 20150302000000 AND DATE < 20200609000000
AND V2location LIKE '%Gabon%'
AND V2themes LIKE '%WB_133_INFORMATION_AND_COMMUNICATION_TECHNOLOGIES%'
GROUP BY theme
ORDER BY 2 DESC
LIMIT 300
обратите внимание на использование V2locations
вместо V2location