เพชรแข็งแค่ไหน ?ไม่จำเป็นต้องใช้ทุกโต๊ะ
how hard is a diamond ?It is not neccessary to use all the tables.
 table_203_385:  id [ number]  "material" [ text]  "formula" [ text]  "hardness\n(mohs'\nscale)" [ text]  "density\n(g/cm3)" [ text]  "thermal\ncond." [ text] 
SELECT "hardness\n(mohs'\nscale)" FROM table_203_385 WHERE "material" = 'diamond'