CREATE TABLE table_22000 ("Name  ( year commissioned ) " TEXT, "Owner/operator" TEXT, "Length" TEXT, "Maximum diameter" TEXT, "From/to" TEXT, "Licence number" TEXT)

What is the length for a diameter totaling 450 mm?
SELECT "Length" FROM table_22000 WHERE "Maximum diameter" = '450 mm'
SELECT "Length" FROM "table_22000" WHERE "Maximum diameter" = '450 mm'