CREATE TABLE table_31619 ("Rank" CLOB, "Nation" CLOB, "Gold" FLOAT, "Silver" FLOAT, "Bronze" FLOAT, "Total" FLOAT)

Tell me the least silver for total less than 6 and rank of 8
SELECT MIN("Silver") FROM table_31619 WHERE "Total" < '6' AND "Rank" = '8'
SELECT MIN("Silver") FROM "table_31619" WHERE "Rank" = '8' AND "Total" < '6'