Question: What is the sum of Solidat (c) that's purpose is display type, heavy duty jobs, and a hardness (brinell) is smaller than 33?
SQL: SELECT SUM("Solidat (°C)") FROM "2-159441-2" WHERE "Purpose" = 'display type, heavy duty jobs' AND "Hardness ( Brinell )" < 33.0;

Question: When the Sn/Sb (%) of 13/17, and a Liquidat (c) bigger than 283 what's the solidat (c)?
SQL: SELECT SUM("Solidat (°C)") FROM "2-159441-2" WHERE "Sn/Sb (%)" = '13/17' AND "Liquidat (°C)" > 283.0;

Question: How many Liquidat (c) have a purpose of dual (machine & hand composition)?
SQL: SELECT COUNT("Liquidat (°C)") FROM "2-159441-2" WHERE "Purpose" = 'dual (machine & hand composition)';