Table: type_metal_data
Columns: sn_sb
liquidat_c
solidat_c
hardness_brinell
purpose

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 type_metal_data WHERE "purpose" = 'display type, heavy duty jobs' AND "hardness_brinell" < 33

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 type_metal_data WHERE "sn_sb" = '13/17' AND "liquidat_c" > 283

Question: How many Liquidat (c) have a purpose of dual (machine & hand composition)?
SQL: SELECT COUNT("liquidat_c") FROM type_metal_data WHERE "purpose" = 'dual (machine & hand composition)'