not working on Postgress

There is a query doesn't work on postgres:

db_query("INSERT INTO {search_total} (word, count) SELECT word, LOG10(1+1/GREATEST(1, SUM(score))) FROM {search_index} GROUP BY word");

the log function is specific for mysql.. you sould use this on postgress

db_query("INSERT INTO {search_total} (word, count) SELECT word, LOG(10, CAST(1+1/GREATEST(1, SUM(score)) as numeric)) FROM {search_index} GROUP BY word");