Table: snowdon_ranger
Columns: name
builder
type
date
works_number

Question: What is the total works number of the locomotive with 0-6-4t type after 1875?
SQL: SELECT SUM("works_number") FROM snowdon_ranger WHERE "type" = '0-6-4t' AND "date" > 1875

Question: What is the total work number of Gowrie after 1875?
SQL: SELECT SUM("works_number") FROM snowdon_ranger WHERE "date" > 1875 AND "name" = 'gowrie'

Question: What is the average work number of Snowdon Ranger with the builder Vulcan Foundry?
SQL: SELECT AVG("works_number") FROM snowdon_ranger WHERE "builder" = 'vulcan foundry' AND "name" = 'snowdon ranger'

Question: What is the total work number of Gowrie with a 0-6-4t type after 1908?
SQL: SELECT COUNT("works_number") FROM snowdon_ranger WHERE "type" = '0-6-4t' AND "name" = 'gowrie' AND "date" > 1908